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January 31, 2003
Lamellar grafting shows promise in the treatment of keratoglobus
OCULAR SURGERY NEWS 2/1/03
Posted by: S.Aliakbari
Posted by saliakbari at 09:30 PM
Tips & Techniques for Laser Phacoemulsification
Ophthalmology management, Dec 2002
All surgeons complete removal of the lens segments in the same way: by holding them at the mouth of the laser/aspiration probe using vacuum and firing the laser to fragment them for aspiration. However, several surgeons have developed different techniques for nuclear disassembly. These include:
Nuclear prechop. This technique, developed by Dr. Dodick himself, involves inserting two Dodick-Kallman Choppers under the anterior capsulotomy, 180° apart and out to the equator of the lens. The surgeon rotates the choppers downward and draws them towards each other, bisecting the lens inside the capsular bag. A similar maneuver then bisects each half. Using the irrigation probe to support the segments during removal is helpful.
Settings: Aspiration: 275 to 300 mmHg; Air infusion: 80 to 100 mmHg; Laser pulses: 1 Hz.
Wehner backcracking. This technique, developed by Wolfram Wehner, M.D., uses the Wehner Spoon, an irrigating handpiece that resembles a shovel at the tip. The surgeon lifts the nucleus using the laser/aspiration probe, inserts the Wehner spoon underneath, and uses the two probes to backcrack the nucleus. The Wehner spoon provides support during removal of the lens segments.
Settings: Aspiration: 275 mmHg; Air infusion: 95 mmHg; Laser pulses: 3 Hz.
Nuclear bowl technique. This technique, modified by Ivan Zerdab, M.D., and Rajeev Raut, M.D., uses the laser/aspiration probe to first lyse the central nucleus and then break up the remaining epinuclear bowl.
Settings: Aspiration: 230 to 240 mmHg; Air infusion: 80 to 100 mmHg; Laser pulses: 2 to 6 Hz.
My personal technique. I use Dr. Dodick's Prechop technique, but I use the Wehner Spoon to help manipulate the lens segments.
My settings: Aspiration: 275 mmHg; Air infusion: 80 to 100 mmHg; Laser pulses: 1 Hz. --
Laurence T. D. Sperber, M.D.
Posted by: S.Aliakbari
Posted by saliakbari at 08:55 PM
The Ascent of Mount Everest Following Laser in situ Keratomileusis
JRS
To report the visual experiences of climbers with prior laser in situ keratomileusis (LASIK) for myopia at extreme altitudes, including the summit of Mount Everest.
We measured the visual acuity of 12 LASIK eyes of 6 Mount Everest climbers at base camp (17,600 ft). Results are reported on their subjective visual experiences, as all climbers ascended above 26,000 feet and four reached the 29,035-foot summitFive of the six climbers reported no visual changes up to 26,400 feet. Three climbers noted no problems and perfect vision with their LASIK eyes on the summit of Mount Everest. One reported mild blurring with ascent above altitudes of 16,000 feet that improved with descent, or a prolonged stay at altitude. Two climbers reported blurred vision at 27,000 and 28,500 feet, respectively, which improved with descent.Laser in situ keratomileusis may be a good choice for patients involved in high altitude activities. Patients achieving extreme altitudes of 26,000 feet and above should be aware of possible fluctuation of vision..
Posted by Alireza Habibollahi,MD
Posted by at 07:55 PM
Neuronal Migration and Glial Remodeling in Degenerating Retinas of Aged Rats and in Nonneovascular AMD Investigative Ophthalmology and Visual Science 2003
In response to loss of RPE and photoreceptor cells, adult retinal neurons migrate out of the retina along remodeled processes of Müller cells. The presence of synaptic vesicle antigens suggests the formation of new synapses between migrating neurons. The myelination is probably due to the ingress of Schwann cells from the sclera. The presence of some similar changes in human AMD retinas suggests that these findings are of broad significance for determining the likely events in transplantation of neurons in the human retina and elsewhere
posted by M.Riazi
Posted by at 07:38 PM
Full Body Heat
SURVEY OF OPHTHALMOLOGY JAN-FEB 2003
An article in Lancet reports that body warming, either whole body or local heat, using radiant heating, can reduce the incidence of post-operative infections after clean surgery. They suggest that this technique may be as effective as preoperative antibiotics.Always looking for ways to be of assistance to our colleagues,we propose that eye surgeons consider the potentials of full body heating.
P0sted by M.Miraftab MD,
Posted by mmiraftab at 03:54 PM
Severe interferon associated retinopathy
BJO Feb 2003
A 56 year old man presented with a 3 week history of deterioration and distortion of right vision. Visual acuities (VA) were 6/60 right and 1/60 left. Funduscopy revealed bilateral extensive peripapillary cotton wool spots, retinal thickening, optic disc hyperaemia, and blot haemorrhages. Arteriolar changes were minimal. He was anaemic (Hb 10.6 gdl/l) and slightly thrombocytopenic (platelets 93 x 109/l). Plasma viscosity was 1.59 (normal 1.5–1.7). Renal function was normal at presentation. He underwent peripheral blood stem cell transplant for multiple myeloma 8 months previously after having melphalan 110 mg/m2 and total body irradiation (including the head) in a total dose of 1200 cGy given in six fractions over 3 days. He then had interferon alfa therapy for 4 months, initially 3 mega units three times a week, later reduced to twice a week. It was stopped immediately after visual deterioration.
Posted by M.Miraftab MD,
Posted by mmiraftab at 02:59 PM
Mechanical Properties of the Human Posterior Lens Capsule
Investigative Ophthalmology and Visual Science. 2003;44:691-696.)
To investigate mechanical properties of the human posterior lens capsule,twenty-five human donor eyes were obtained from an eye bank. The age of the donors ranged from 1 to 94 years. Data for the posterior lens capsule were compared with previously published data for the anterior lens capsule.
The thickness of the posterior lens capsule ranged from 4 to 9 µm and showed no significant changes with age. Ultimate mechanical strength of the posterior lens capsule decreased significantly with age. Ultimate strain ranged from 101% to 34%, ultimate load ranged from 15.9 to 1.1 mN, .....
CONCLUSIONS. .... The age-related loss of mechanical strength seemed to begin earlier in the posterior lens capsule than in the anterior lens capsule. In accommodative function range (low strains), the mechanical quality of the posterior lens capsule was similar to the anterior lens capsule, which indicates that the mechanical effectiveness of the lens capsule in situ varies proportionally with capsular thickness.
posted by A.Gholaminejad, MD
Posted by agholami at 02:55 PM
Posterior corneal topographic changes after partial flap during laser in situ keratomileusis
Br J Ophthalmol 2003;87:160–162
Aim: To study the posterior corneal topographic changes in eyes with partial flaps during laser assisted in situ keratomileusis (LASIK).
Methods: Case records of 16 patients, who had partial flap in one eye during LASIK (group 1) and uncomplicated surgery in the other eye (group 2), were studied. Following occurrence of partial flap intraoperatively, laser ablation was abandoned in all the eyes. A 160/180 µm flap was attempted during the initial procedure using the Hansatome microkeratome . LASIK surgery in all cases was performed using a 180 µm plate, at the mean interval of 4.16 (SD 1.5) months following the initial procedure. None of the eyes had intraoperative complication during LASIK. Relative posterior corneal surface elevation above the best fit sphere (BFS) before the initial procedure, before, and after LASIK were compared using the Orbscan slit scanning corneal topography/pachymetry system.
Results: Posterior corneal elevation was comparable in the two groups, both preoperatively (group 1;16.4 (4.8) µm, group 2; 16.1 (4.8) µm) and after final surgery (group 1; 57.2 (15.6) µm, group 2;54.3 (13.1) µm). In group 1 after occurrence of partial flap, the posterior corneal elevation was 16.9(4.4) µm, and this increase was not significant statistically (p=0.4). On multiple linear regression analysis,residual bed thickness (p<0.001) was independently the significant determinant of final posterior
corneal elevation in both groups.
Conclusion: The inadvertent occurrence of partial flap during LASIK procedure does not contribute to the increase in posterior corneal elevation.
Posted by M.Miraftab MD,
Posted by mmiraftab at 02:47 PM
January 29, 2003
In vivo confocal microscopy of the human cornea
I Jalbert1, F Stapleton1, E Papas1, D F Swee
BJO Feb 2003
Confocal microscopy allows ophthalmic clinicians and researchers to visualise living tissues at greatly increased resolutions. Qualitative observations of the images obtained are rapidly giving way to sophisticated quantitative image analysis systems. So far, confocal microscopy has been used to better characterise the often rare corneal degenerations and dystrophies, as an aid in the differential diagnosis of keratitis and keratopathies, to research the wound healing characteristics of the human cornea following penetrating keratoplasties and refractive surgery procedures, and to study the effects of contact lens wear. Confocal microscopy has also been successfully used in lieu of specular microscopy to obtain endothelial cell counts even in the presence of oedema.
See More ...
Posted by : M.Tabrizi.MD
Posted by mtmdop at 06:48 AM
Delayed Optic Nerve Decompression for Indirect Optic Nerve Injury A.
Laryngoscope 2003; 113(1):112-119
Objective: To test the efficacy of delayed optic nerve decompression in traumatic optic nerve injury.
Conclusions: Optic nerve decompression remains useful as a salvage procedure for conventional dose steroid failed cases of traumatic optic neuropathy. In cases that are not completely blind, vision can be improved even when surgery is undertaken a few months after the injury.
posted by Pakravan M.D.
Posted by at 01:06 AM
Corneal Thickness Measurements and Visual Function Abnormalities in Ocular Hypertensive Patients
ajo/ feb/ 2003
Ocular hypertensive (OCT) patients with abnormal short- wavelength automated perimetry (SWAP) results had thinner central cornea than OHT patients with normal SWAP results, suggesting that corneal thickness should be taken into account when assessing the risk of glaucoma development among OHT subjects
posted by Pakravan M.D.
Posted by at 12:45 AM
January 28, 2003
Macular Thickness Changes in Glaucomatous Optic Neuropathy Detected Using Optical Coherence Tomography
Arch Ophthalmol.2003
To correlate macular thickness and retinal nerve fiber layer (RNFL) thickness in normal and glaucomatous eyes using optical coherence tomography, complete examination, automated achromatic perimetry, and optical coherence tomography of the peripapillary RNFL and macula were performed in fifty-nine eyes of 59 patients (29 normal and 30 glaucomatous). All eyes with glaucoma had associated visual field loss. Mean macular thickness was significantly associated with visual field mean defect (R2 = 0.47; P<.001), pattern standard deviation (R2 = 0.32; P<.001), and mean RNFL thickness (R2 = 0.38; P<.001) and the study showed that macular thickness changes are well correlated with changes in visual function and RNFL structure in glaucoma and may be a surrogate indicator of retinal ganglion cell loss.
posted by:K.H.Jalali,MD.
Edited by M Khanlari MD
Posted by kjalali at 08:41 PM
Increasing Retinal Antioxidant Levels Might Influence Macular Function
Increasing antioxidant levels in the retina might influence macular function in early age-related maculopathy as well as during normal aging. Researchers from the Universita Cattolica del S Cuore, Rome, Italy, enrolled 30 patients with early age-related maculopathy and a visual acuity of at least 20/30 as well as eight age-matched normal ...Full Story
Posted by A R Naderi MD,
Posted by Ali Reza Naderi at 01:23 PM
Retinal detachment after cataract extraction and refractive lens exchange in highly myopic patients
(JSCRS Jan 2003)
Refractive lens exchange led to good functional results and a low incidence of postoperative complications and can thus be regarded as a viable technique to correct high myopia associated with cataract. However, further study is required before it can be routinely recommended for the correction of high myopia in eyes with a transparent crystalline lens.
Posted by A R Naderi MD,
Posted by Ali Reza Naderi at 01:11 PM
(JSCRS Jan 2003)
Intravitreal triamcinolone acetonide for refractory chronic pseudophakic cystoid macular edema In this nonrandomized retrospective case review, 8 eyes of 8 patients with a history of pseudophakic CME recalcitrant to current standard treatment modalities were enrolled. The mean duration of the CME was 20 months. The patients received intravitreal injections of 1 mg of TAAC and were followed for a mean of 8 months. The main outcome measures included visual acuity, the presence of CME on biomicroscopic examination, angiographic evidence of perifoveal leakage, intraocular pressure (IOP), and complications related to treatment.The visual acuity increased in all patients. The magnitude of improvement was mainly restricted by underlying macular pathology and correlated well with the level of visual acuity at entry into the study. Angiographic improvement occurred in all patients. Temporary increases in IOP were easily controlled with topical medications. No other adverse effects could be attributed to this technique. Repeated injections were required.Intravitreal administration of TAAC was safe and effective in recalcitrant cases of pseudophakic CME with a beneficial effect on the macular edema and visual acuity. Repeated injections were required in all eyes. The development of a sustained-release intravitreal drug-delivery system would be beneficial.
Posted by A R Naderi MD,
Posted by Ali Reza Naderi at 01:00 PM
Management of posterior polar cataract
(jscrs jan 2003)
I. Howard Fine MDa, 1, Mark Packer MDa, , 1 and Richard S. Hoffman MDa, 1
In this technique for managing posterior polar cataract, extreme care is taken not to overpressurize the anterior chamber or capsular bag to prevent posterior capsule rupture. Minimal hydrodissection and hydrodelineation are performed. The nucleus is extracted using minimal ultrasound energy. Viscodissection is used as a primary technique to mobilize the epinucleus and cortex. A protective layer is preserved over the posterior polar region until the conclusion of the extraction procedure to minimize the risk of loss of lens material into the vitreous cavity in the case of a capsule defect.
Posted by A R Naderi MD,
Posted by Ali Reza Naderi at 12:48 PM
Autorefractometry after laser in situ keratomileusis
Sciencedirect.com
Subjective refraction and autorefractometry under cycloplegia were performed in 73 eyes of 46 patients 1, 6, and 12 months after LASIK to correct myopia or myopic astigmatism. The preoperative subjective refraction and autorefractometry under cycloplegia in the same eyes served as controls.A statistically significant difference between subjective refraction and autorefraction was found in the sphere and cylinder at all postoperative times. No statistically significant difference was found in the axis. There was no statistically significant difference in the control eyes.Automated refractometry in eyes that had had LASIK was reliable in the axis only. Retreatments after LASIK should always be based on subjective refraction.(JCRS jan 2003)
Posted by A R Naderi MD,
Posted by Ali Reza Naderi at 12:38 PM
Central and peripheral corneal thickness measurement with Orbscan II and topographical ultrasound pachymetry*1, *2 (JSCRS Jan 2003)
In 24 right eyes, pachymetric measurements were taken at the center and 1.2 mm and 3.0 mm on the superior and inferior hemimeridians. A 1-sample t test was applied to assess the significance of the relationship between Orbscan II and ultrasound methods. The relationship between the 2 was assessed by analyzing regression and plotting the differences against the mean corneal thickness. Orbscan II data were analyzed in 3 ways: (1) without the application of an acoustic equivalent correction factor; (2) with a correction factor of 0.92, as recommended by the manufacturer; (3) with correction using the equations derived in this study. The data were systematically compared with those of ultrasound pachymetry.Before the correction factor was applied, the Orbscan II overestimated the corneal thickness at all locations, with the mean difference (48.15 m ± 33.74 [SD]) significantly different from zero (P < .001). Differences increased toward the periphery, and the reliability of Orbscan II readings seemed to decrease with thicker corneas. After the acoustic equivalent was applied, the differences were significantly less; however, this effect did not seem clinically significant as large differences remained. When specific corrective equations were applied for each corneal location, the level of agreement between Orbscan II and ultrasound pachymetry improved substantially; the mean (–0.11 ± 15.22 m) was not statistically different from zero (P > .05).The acoustic equivalent correction factor proposed by the manufacturer to obtain corneal thickness measurements with the Orbscan II compared to those from ultrasound pachymetry was not valid for all corneal topography positions. Orbscan II measurements agreed better with those of ultrasound pachymetry when equations for the central and each peripheral location across the topography were applied.
Posted by A R Naderi MD,
Posted by Ali Reza Naderi at 12:28 PM
Prediction of improved vision in the amblyopic eye after visual loss in the non-amblyopic eye
Journal of AAPOS,December,2002
The purpose of this study was to establish the likelihood of predictive factors for improvement of vision of the amblyopic eye after visual loss in the nonamblyopic eye. Only patients 11 years of age or older at presentation were included.
Two hundred fifty four subjects were included in this analysis. An increase in acuity in the amblyopic eye at 1 year was reported in 48 subjects (18%), and improvement in acuity of 2 or more lines was noted in 25 (10%). The authors conclude that a few visually mature people with amblyopia have some plasticity in their visual systems.
†Posted by A.Farahi M.D
Posted by afarahi at 01:25 AM
Amblyopia treatment outcomes after screening before or at age 3 years
Journal of AAPOS,December,2002
A recent review of the literature suggested that there is little evidence that early treatment for amblyopia is more effective than later treatment and that preschool vision screening programs should be discontinued. The purpose of this study was to assess the effectiveness of early treatment for amblyopia in children. The participants were randomized into a control group or a study group. The children in the control group were offered a strabismus and vision screening examination by an orthoptist at age 37 months. The study group were offered a strabismus and vision screening examination by an orthoptist at age 8, 12, 18, 25, 31, and 37 months. . The final assessment was made when the children were 7.5 years of age . The prevalence of amblyopia of 2 lines or greater difference was 1.45% for the study group and 2.66% for the control group (P = .06). The prevalence of amblyopia of 3 lines or greater difference was 0.65% for the study group and 1.81% for the control group (P = .02). Mean visual acuities in the worse-seeing eye were better for children who had been treated for amblyopia in the study group than for similar children in the control group (0.15 vs 0.26 LogMAR units; P < .001).
<i>The authors suggest that their data support the hypothesis that early treatment for amblyopia leads to a better outcome than later treatment.
Posted by A.Farahi
Posted by afarahi at 01:17 AM
Long term follow up of bone derived hydroxyapatite orbital implants
B.J.O,November,2002
This retrospective case series reviewed the long term follow up of 118 patients with 120 eyes which had undergone enucleation and bone derived hydroxyapatite orbital implant insertion at Dunedin Hospital from 1977 until 2000.
Of this 120 eyes 84 had bone derived hydroxyapatite orbital implants with sclera and 36 without sclera. complications were more likely in cases with major tissue disruption, ischaemia, or inflammation. There were significantly fewer complications in the group where a bone derived hydroxyapatite orbital implant was implanted without a scleral covering (p<0.05). The authors conclude:The placement of a bone derived hydroxyapatite orbital implant in the socket was associated with a low rate of long term complications and good cosmesis in most cases.The use of scleral cap unexpectedly increased the incidence of complications . The omission of a scleral covering over the hydroxyapatite sphere had some advantages and may prove to be the procedure of choice.
Posted by A.Farahi
Posted by afarahi at 01:02 AM
Effect of aging on human rectus extraocular muscle paths demonstrated by magnetic resonance imaging
A.J.O , December, 2002
According to this experimental study: Compared with images obtained using identical technique in 12 younger subjects (average age, 28.5 years, range 21–33), the horizontal rectus EOMs in the 12 older subjects were significantly displaced inferiorly throughout the anteroposterior extent of the orbit. The vertical rectus EOM was positioned identically to those of younger subjects.The authors conclude:The horizontal rectus EOMs are displaced inferiorly in the elderly relative to the globe center. This displacement presumably reflects an inferior location of the corresponding pulleys, partially converting horizontal rectus EOM force to depression. This may contribute to the observed impairment of elevation in older people and predispose them to a characteristic pattern of incomitant strabismus.
Posted by A.Farahi
Edited by M Khanlari MD
Posted by afarahi at 12:12 AM
January 27, 2003
Refractive Errors Associated with Ocular Hypertension, Glaucoma
AAO.org January 9, 2003
SAN FRANCISCO – Farsightedness in Caucasians appears to be associated with a five-year risk of ocular hypertension, and nearsightedness is associated with a significantly increased prevalence of glaucoma. Previous studies have shown the association between nearsightedness and glaucoma. However, this is the first time an association between farsightedness and ocular hypertension has been found. The study found farsighted participants were 40 percent more likely to have incident ocular hypertension than those without refractive error. Incident ocular hypertension is high intraocular pressure with no apparent damage to the optic nerve and visual field defects that characterize glaucoma, though glaucoma may develop with time. The study also found nearsighted participants were 60 percent more likely to have glaucoma than those without refractive error. The authors state they have “no adequate explanation” for the association between farsightedness and ocular hypertension, but note that farsightedness has been associated with primary angle-closure glaucoma, though rare in Caucasians. The authors say the shallower front chamber of the eye may predispose a person to higher intraocular pressure. They also say it is possible farsightedness “may simply be a marker for biologic aging,” and they point out they have previously reported an association between farsightedness and two types of cataract. They call for further research to explain these associations.
Posted by M Khanlari MD
Posted by at 11:14 PM
Conductive keratoplasty has good results for hyperopia at 6 months
O S N
NICE, France — Conductive keratoplasty appears to be a safe and effective technique for the correction of low hyperopia and hyperopic astigmatism, at least at the 6-month mark, according to a study presented here.“The procedure seems to be safe, and the results of uncorrected visual acuity are stable up to the 6-month period,” said Ioannis Pallikaris, MD,. In the study, conducted at the University of Crete Medical School, 39 eyes in 18 men and 21 women were treated for low hyperopia of up to +3.25 D and astigmatism of up to –5.75 D. “In the surgery, we treated the spherical component first. We used the straddling technique. The laser spots were put on the flat meridian of the astigmatism,” Dr. Pallikaris explained. At 6-month follow-up, mean uncorrected vision improved from 20/40 preop to 20/25. “We were very happy to see that that no one lost lines of acuity, and five eyes gained 1 line of best-corrected visual acuity,” he said. The manifest spherical equivalent refraction also improved at the 6-month mark, from mean +1.5 D preop to a mean of –0.31 D for all eyes. “We expect these numbers to remain stable, and the use of conductive keratoplasty to become a viable option for those with naturally occurring and induced hyperopia and hyperopic astigmatism,”
Posted by Alireza Habibollahi,MD
Edited by M Khanlari MD
Posted by at 10:38 PM
Corneal Topographic Changes After Retinal Detachment Surgery
Cornea,November,2002
Twenty-one eyes of 21 patients with the diagnosis of retinal detachment were included in this prospective study. Scleral buckling surgery was performed on all patients. The corneal topography of each was measured before surgery and at 1 week and 1 and 6 months after surgery .A statistically significant central corneal steepening (average, 1.8 diopter) was noted 1 week after surgery. The total and irregular astigmatic components both revealed a significant but transient increase in the first postoperative month. All these topographic changes persisted for as long as 6 months but returned to preoperative values afterward.
Scleral buckling was found to induce transient changes in corneal topography producing both myopia and corneal astigmatism.
Posted by:Sh.Ebadollahi.M.D.
Posted by at 10:14 PM
Treatment of Recurrent Corneal Erosions Using Autologous Serum
Cornea,November,2002
Eleven eyes of 11 consecutive patients with acute macroform corneal erosions who had suffered several relapses despite receiving different types of treatment were analyzed from November 2000 to February 2002. All patients were treated with autologous serum for 3 months. Treatments prior to the use of autologous serum had failed to avoid recurrences in all the patients, with the mean recurrence rate being 2.2 recurrences per month of follow-up. After the onset of serum treatment, only a single recurrence was recorded in three of the patients (0.028 recurrences per month of follow-up).
Conclusion:
The use of autologous serum for the treatment of patients with recurrent corneal erosion is effective and safe in reducing the number of recurrences experienced by patients.
Posted by:Sh.Ebadollahi.M.D.
Posted by at 10:02 PM
Influence of short-term antioxidant supplementation on macular function in age-related maculopathy. A pilot study including electrophysiologic assessment
Ophthalmology Jan 2003,
: At 180 days, FERGs of ARM-A(with antioxidants) patients and N-A(normals with antioxidants) patients were increased in amplitude (mean change, 0.11 and 0.15 log µV, respectively, P 0.01) compared with baseline values, whereas no significant changes in FERG amplitudes of ARM-NT(no tx.) patients and N-NT(normals with no Tx.) patients were found (mean change, -0.004 and -0.023 log µV, respectively). In all groups no changes in the FERG phase were found. FERG modulation thresholds decreased with respect to baseline values (mean change, -0.36 log units, P < 0.01) in ARM-A patients, whereas no significant change (mean change, 0.07 log units) in ARM-NT patients was seen. At 360 days, FERGs of ARM-A patients taking supplementation were still increased in amplitude with respect to baseline (P < 0.05) but did not differ from those recorded at 180 days. In the patient who had discontinued supplementation, FERG amplitude decreased from the 180 days value, approaching that recorded at baseline.
CONCLUSIONS: Although this study provides no evidence for the long-term benefit of antioxidants in ARM, the results suggest that increasing the level of retinal antioxidants might influence macular function early in the disease process, as well as in normal aging.
posted by M.Riazi
Posted by at 12:21 AM
Five-year cumulative incidence and progression of epiretinal membranes
Ophthalmology Jan 2003,
Epiretinal membranes developed in the first eye of 108 of 2030 participants who had no sign of this condition in either eye at baseline, 5.3%, 95% confidence interval (CI) 4.4 to 6.4. Five-year cumulative incidence rates for PMF and CMR were 1.5% and 3.8%, respectively. Of those participants with epiretinal membranes in one eye at baseline, 18 of 133 (13.5%) developed this sign in their second eye after 5 years. New epiretinal membranes (mostly CMR) occurred in 15 of 165 subjects (9.1%; CI, 5.2–14.6) who had undergone cataract surgery since the Blue Mountains Eye Study I. This rate was significantly higher than in the nonsurgical group, 92 of 1861 (4.9%; CI, 4.0–6.0) of whom developed epiretinal membranes. Progression from CMR to PMF was observed in 17 of 183 eyes (9.3%). Existing epiretinal membranes progressed, regressed, or remained stable in 28.6%, 25.7%, and 38.8% of eyes, respectively.
posted by M.Riazi
Posted by at 12:07 AM
January 26, 2003
Early age-related maculopathy in the cardiovascular health study
Ophthalmology Jan 2003,
Early ARM was present in 15.5% and late ARM in 1.3% of the cohort. The overall prevalence of any ARM was lower in blacks (9.1%) compared with whites (18.2%). While controlling for age, race, gender, and total calories consumed in the diet, factors associated with ARM were cerebral white matter disease as detected by magnetic resonance imaging (odds ratio [OR], 1.50; 95% confidence interval [CI], 1.05, 2.16, P = 0.027), and lower serum total cholesterol (OR, per 10 mg/dl increase 0.95; 95% CI, 0.91, 0.98, P = 0.02). There were no associations between hypertension, blood pressure, common carotid artery plaque, or any systemic inflammatory factors studied and early ARM.
posted by M.Riazi
Posted by at 11:59 PM
Anaesthesia-related diplopia after cataract surgery
Br J Anaesth 2003; 90: 189–92
The incidence and clinical characteristics of persistent diplopia related to anaesthesia for cataract surgery in a general hospital is reported in this study, This was a retrospective review of anaesthesia for 3587 cataract surgeries(3450 by phacoemulsification and 137 by extracapsular extraction),Retrobulbar block was used in 2024 cases, peribulbar block in 98, topical anaesthesia in 1420 and general anaesthesia in 43.....
Conclusions. Persistent diplopia can occur after cataract surgery using retrobulbar block predominantly through direct damage to the inferior rectus muscle. The overall incidence of anaesthesia-related diplopia in this series was 0.25%.
posted by A.Gholaminejad,MD
Posted by agholami at 09:42 PM
January 25, 2003
Recurrence of keratitis after excimer laser keratectomy
JCRS January 2003
Reportage of 3 patients who experienced a recurrence of nonherpetic keratitis after excimer laser photorefractive surgery. Two patients had a history of culture-positive adenoviral keratoconjunctivitis, and 1 had a clinical diagnosis of Thygeson's superficial punctate keratitis (SPK) prior to excimer laser surgery. Patients should be informed that excimer laser surgery may contribute to a recurrence of keratitis and Thygeson's SPK. Recognition and appropriate treatment can result in resolution and maintenance of a good refractive outcome.
Posted by M.Miraftab MD,
Posted by mmiraftab at 11:39 PM
Corneal ectasia after LASIK
JCRS January 2003
Iatrogenic corneal ectasia after laser in situ keratomileusis (LASIK) is an insidious and feared complication. It can be avoided by identifying the associated risk factors. When analyzing the reported cases of corneal ectasia, one should consider the numerous potential sources of error in calculating the theoretical residual bed thickness (RCB) and the difficulties in identifying form fruste keratoconus (FFK).
Of 62 cases of ectasia that we reviewed, 48 (78%) occurred in an eye with FFK or after a high myopic treatment leaving a thin RCB (less than 250 m) and 14 (22%) occurred in normal corneas after a low-to-moderate myopic treatment leaving a sufficient RCB (greater than 250 m). Of the latter cases, 7 (50%) had preoperative pachymetry less than 500 m, suggesting that a thin corneal thickness could represent a risk factor for ectasia and that thin corneas, similar to those with FFK, are more prone than normal corneas to develop ectasia.
The effect of a large-diameter optical zone (OZ) on the occurrence of ectasia is well illustrated that eyes with an RCB greater than 250 m had a larger OZ treatment (6.00 mm versus 5.65 mm) than eyes with an RCB less than 250 m.we postulate that the OZ diameter might play a role, not only its effect on the ablation depth, but also its effect on the estimation of the ablated tissue volume. the estimated ablation volume of stromal tissue is twice as important in a 6.0 mm OZ than a 5.0 mm OZ. The volume of tissue ablation could be an important element in the biomechanical structure of the cornea. FFK corneas commonly develop inferior ectasia more often whereas normal corneas commonly develop central ectasia more often. Thus, the occurrence of an inferior ectasia could retrospectively suggest the existence of FFK preoperatively.
Posted by M.Miraftab MD.
Posted by mmiraftab at 11:31 PM
Treatment of Rubeosis iridis with Photodynamic Therapy with Verteporfin - A New Therapeutic and Prophylactic Option for Patients with the Risk of Neovascular Glaucoma?
ophthalmic research january 2003
Patients with ischaemic retinopathy who show iris neovascularization despite panretinal laser photocoagulation (PRP) very often develop a neovascular glaucoma. Photodynamic therapy (PDT) has been shown to occlude neovascularization without damage to physiologic vessels or adjacent tissue in the treatment of choroidal neovascularization (CNV) and might also be of value for patients with neovascular glaucoma who did not benefit from the PRP. First results of a monocentre, open label, intra-individual controlled, pilot phase I/II, dose-finding study demonstrate that PDT with verteporfin is capable of occluding neovascular vessels for a defined period of time without damaging adjacent tissue or physiologic iris vessels. Whether this vessel occlusion will have an impact on the progression of rubeosis or neovascular glaucoma will be the subject of further investigation.
Posted by M.Miraftab MD,
Posted by mmiraftab at 10:20 PM
Iatrogenic keratectasia: current knowledge, current measurements
JCRS dec 2003
The general thinking is that residual post-LASIK stromal thickness should not be less than 250 ěm. Obviously, precise measurement of the overall corneal thickness and the thinnest corneal point is mandatory; preoperatively, to include or exclude patients; intraoperatively, to abort the ablation; and postoperatively, to qualify patients for further treatment (overcorrection, undercorrection, or irregular astigmatism).Rainer et al. report an interesting result of corneal thickness measurements. The mean corneal thickness measured with 3 ultrasound pachymetry devices was similar but statistically different. The measurement with partial coherence interferometry (PCI) was about 20 ěm to 26 ěm thinner than the ultrasonic measurements; PCI was the more precise method, with better intraobserver variability. This shows that the measurement of corneal thickness for LASIK requires careful attention to determine the “real” value. Perhaps better devices than those currently in use are necessary.For the clinician, the important steps in preventing keratectasia have been summarized :
(1) Evaluate topography and pachymetry before each case.
(2) Avoid LASIK in eyes with abnormal or suspicious topography.
(3) Calculate the estimated residual posterior corneal thickness based on corneal thickness, ablation depth, and anticipated flap thickness.
(4) Measure flap thickness and posterior corneal thickness intraoperatively.
(5) Collect, evaluate, and report keratectasia cases.
I would like to propose an additional guideline that I now follow in my practice: Do not perform LASIK in patients with corneas less than 500 ěm at the thinnest point. The effort to identify corneas that could develop keratectasia after ablation surgery, particularly lamellar procedures, should continue. The upper limits of LASIK in each individual case will primarily depend on this identification and on quality-of-vision issues.
Posted by M Khanlari MD
Posted by at 07:48 PM
what is diagnosis and How would you proceed?
66-year-old physician was referred for reduced distance vision in the left eye. The history revealed that the patient had uneventful bilateral cataract surgery 8 years earlier and that the intraoperative and postoperative courses were routine and uneventful. However, the patient recently observed a change in vision in the left eye. An ocular examination revealed the following findings: an uncorrected visual acuity of 20/20 in the right eye and 20/100 in the left eye and a best corrected visual acuity (BCVA) of 20/20+ and 20/20, respectively. Refraction is –0.25 diopter (D) sphere in the right eye and –1.50 D sphere in the left eye. The intraocular pressure (IOP) is 18 mm Hg bilaterally.Anterior segment examination reveals bilaterally clear corneas and deep and quiet anterior chambers. In both eyes, there are 3-piece intraocular lenses (IOLs) well-placed in the capsular bag and the anterior capsulorhexis covers the edge of the IOL for 360 degrees.
However, in the left eye, there is an enlarged space between the optic and the posterior capsule. The retrolenticular space contains fluffy white material inferiorly and a turbid gray opalescent material superiorly Figure : Postoperative view of the left eye; note the white material behind the IOL. A posterior segment examination demonstrates quiet vitreous cavities with bilateral posterior vitreous detachments and normal optic nerves, maculae, and peripheral retinal details.The patient is visually uncomfortable with the recently induced uniocular myopia in the left eye and requests correction of the problem.
Posted by M Khanlari MD
Posted by at 07:12 PM
Optical Coherence Tomography for the Detection of Laser In Situ Keratomileusis in Donor Corneas
Cornea jan 2003
In 2001, more than one million laser in situ keratomileusis (LASIK) procedures were performed worldwide. Considering the increasing number of refractive procedures, eye banks will be increasingly confronted with the problem of how to identify those donors with prior refractive surgery. To date, efficient screening methods to identify LASIK surgery in donor eyes have not been established. Therefore, the purpose of the current study was to determine whether optical coherence tomography (OCT) can be used to detect the presence of LASIK-induced changes in human corneas.Laser in situ keratomileusis was performed on 20 organ-cultured human cornea disks. The excimer laser ablation performed ranged from 0 to 12 diopters. The corneas were maintained in culture, and the visibility of flap-stromal interface by OCT was assessed up to 6 months after the LASIK procedure. Additionally, two donor corneas with the history of LASIK treatment before death were screened for structural changes.Optical coherence tomography scans were able to detect the interface between the corneal flap and the residual stromal tissue in all corneas and at all examined time intervals. There were no differences in signal intensity among the different depths of ablation. The relative signal intensity of the interface compared with the averaged stromal intensity ranged from 2.1 to 6.0. In both donor corneas with suspected prior LASIK surgery, OCT scanning showed the characteristic stromal interface as found in the in vitro model.Conclusions. Corneal examination by OCT could be an appropriate technique for eye banks to screen donor corneas for prior LASIK surgery.
Posted by M Khanlari MD
Posted by at 06:30 PM
A 34 year old man with a dull ache around his left eye
The patient is a 34 year old man with a complaint of a dull ache around his left eye for two days. His past ocular history was remarkable only for similar episodes that resolved spontaneously.
POHx: None PMHx: Non-contributory Meds: acetominophen SHx: Non-contributory
FHx: Non-contributory Vision: 20/20 OD; 20/25 OS
External exam: 
Figure 1The patient's external features were normal. The left pupil can be seen to be slightly larger than the right pupil. Pupils: 3 --> 2 OD 4 --> 3 OS Motility: Full OU
Slit lamp examination: 
Figures 2-3 Corneas were clear bilaterally. Conjunctiva were white and quiet OU. The anterior chambers appeared deep OU. There was 1+ flare and rare cell in the anterior chamber OS. The anterior chamber OD was quiet. Irides and lenses appeared normal.
Intraocular pressure: 15 mm Hg OD, 45 mm Hg OS Gonioscopy: Angles open 360 degrees OU. No synechiae present or neovascularization.
Posted by M Khanlari MD
Posted by at 05:59 PM
January 24, 2003
Do ophthalmic nonsteroidal anti-inflammatory drugs reduce the pain associated with simple corneal abrasion without delaying healing?
Ann Emerg Med. 2003;41:134-140
Some studies have suggested that ophthalmic nonsteroidal anti-inflammatory drugs (NSAIDs) decrease the pain associated with corneal abrasions without impairing healing. This evidence-based emergency medicine (EBEM) critical appraisal reviews the literature, including additional studies appearing since the publication of an earlier EBEM review in 1999. The qualitative summary indicates that NSAIDs provide greater pain relief and improvement of other subjective symptoms when compared with placebo. However, whether the reduction of pain, as measured by visual analog pain scales, exceeds the minimal clinically significant difference is equivocal. The use of ophthalmic NSAIDs may decrease the need for sedating analgesics. Ophthalmic NSAIDs appear to be useful for decreasing pain in patients with corneal abrasions who can afford the medication and who must return to work immediately, particularly where potential opioid-induced sedation is intolerable.
Posted by M Khanlari MD
Posted by at 09:14 PM
Presbyopia: no perfect option yet, surgeon say
OCULAR SURGERY NEWS 10/19/02
ORLANDO, Fla. — None of the three approaches currently used to correct presbyopia is an ideal solution; standard, said Michael Knorz, MD, This three current approaches to surgical correction of presbyopia are 1.monovision, 2.pseudoaccommodation and 3. restoration of accommodation. Monovision can be achieved using any refractive procedure. Conductive keratoplasty offers some advantages over other similar hyperopic correction measures. “Distribution of heat with CK is more homogenous in the tissue. Scars are more predictable, effects more lasting.While monovision works to correct presbyopia, it involves a compromise, It reduces stereopsis, reduces distance vision and does not offer perfect near vision and also that in the United States, monovision has a 70% patient acceptance rate, but in Germany, the acceptance rate is “more like 10% to 20%.Pseudoaccommodation can be achieved with multifocal IOL implantation, To date, results with this approach are imperfect, The compromise is slightly reduced distance vision, not perfect near vision, halos and ghosting. It's not acceptable to everyone, but it is a feasible option.” Restoration of accommodation might be achieved with several surgical procedures, “but all the data is experimental.
Posted by Alireza Habibollahi
Edited by M Khanlari
Posted by at 08:52 PM
u p d a t e / r e v i e w
Possible adverse effects of drugs used in refractive surgery
J Cataract Refract Surg 2003; 29:170–175
Frederick W. Fraunfelder, MD, Larry F. Rich, MD
The reported side effects of mydriatics, cycloplegics, benzodiazepines,tetracyclines, iodine, topical anesthetics, medications used for hemostasis, nonsteroidal antiinflammatory drugs, steroids, antibiotics, and artificial tears are described.Physicians should be aware of the side-effect profile and current industry standards for medications used in corneal refractive surgery, including off-label uses. Guidelines are provided for some classes of medications.
Posted by M.Miraftab MD,
Posted by mmiraftab at 03:48 AM
Is normal tension glaucoma actually an unrecognized hereditary optic neuropathy?
Current Opinion in Ophthalmology 2002; 13(6):362-370
Lawrence M. Buono, MD; Rod Foroozan, MD; Robert C. Sergott, MD; Peter J. Savino, MD
Normal tension glaucoma and dominant optic atrophy share many overlapping clinical features, and differentiating between these two diseases is often difficult. The gene responsible for dominant optic atrophy is the OPA1 gene located on chromosome 3. This gene encodes for a protein product that is involved in mitochondrial metabolic function. Recent genetic linkage analysis of patients with normal tension glaucoma has shown an association with polymorphisms of the OPA1 gene. This association suggests that normal tension glaucoma may actually be a hereditary optic neuropathy with a pathophysiology based in mitochondrial dysfunction.
read also more in EDITORIAL of Optic neuropathy (The OPA1 gene and optic neuropathy) in BMJ
Posted by M.Miraftab MD,
Posted by mmiraftab at 02:57 AM
The Latest Data on IOL Use
ophthalmology management January 2003
The use of hydrophobic and hydrophilic acrylics and collagen co-polymer lenses is outpacing the use of silicone at an increasing rate despite the fact that most doctors agree that shape of the lens edge is more important than material in reducing postoperative complications such as glare and epithelial cell proliferation
Posted by M.Mirafab MD,
Posted by mmiraftab at 02:09 AM
BOTOX Cosmetic
ophthalmology management January 2003
Clinical Pearls
Clinicians offer the following tips for Botox administration:
Watch the depth of the target muscle. To minimize side effects, administer Botox not only in the correct location of the muscle but also at the right depth. Consider wearing a loop to discover (and avoid) blood vessels. Don't jab the needle into the patient. Do one injection at a time, followed by gentle pressure. Try to hide the needle from the patient. To help prevent hematoma, apply small pressure on the site after injection. Avoid overtreating a wide area such as the forehead, especially for new patients. Your patient may dislike the feeling of a weak brow or forehead muscle. Wait at least 2 weeks before reinjecting, to account for any delayed onset. Have a good mechanism (perhaps a facial diagram) to chart treatments.
Posted by M.Miraftab MD,
Posted by mmiraftab at 01:45 AM
January 23, 2003
Macular Thickness Changes in Glaucomatous Optic Neuropathy Detected Using Optical Coherence Tomography
archives of ophthalmology/ jan/ 2003
To correlate macular thickness and retinal nerve fiber layer (RNFL) thickness in normal and glaucomatous eyes using optical coherence tomography. Macular thickness measurements were generated using 6 radial optical coherence tomographic scans (5.9 mm) centered on the fovea, and mean and quadrantic macular thickness values were calculated.Conclusions: Macular thickness changes are well correlated with changes in visual function and RNFL structure in glaucoma and may be a surrogate indicator of retinal ganglion cell loss.
posted by pakravan M.D.
Posted by at 10:40 PM
Microbial contamination of the anterior chamber during phacoemulsification
J Cataract Refract Surg 2002; 28:2173–2176
Anterior chamber fluid aspirates were positive for bacteria in 37 eyes (46.25%). Coagulase-negative Staphylococcus was the most common aerobe and Propionibacterium acnes, the most common anaerobe. Conclusion: Results indicate that phacoemulsification has no proven advantage over conventional extracapsular cataract extraction in reducing intraoperative bacterial contamination.
posted by pakravan M.D.
Posted by at 10:09 PM
A six-month randomized clinical trial comparing the intraocular pressure-lowering efficacy of bimatoprost and latanoprost in patients with ocular hypertension or glaucoma
ajo, jan, 2003
Bimatoprost is more effective than latanoprost in lowering IOP. Both drugs were well tolerated, with few discontinuations for adverse events.
posted by M. Pakravan
Edited by M.Khanlari
Posted by at 09:33 PM
Decentered Hyperopic LASIK with an Existing Off-Center Corneal Apex
Review of Refractive Surgery,Jan,2003
Corneal topographies show the right and left eyes of a 40-year-old patient 12 months s/p bilateral hyperopic LASIK for +3 D in each eye. Preoperatively, the examination was unremarkable with 20/20 best corrected visual acuity OU.In contrast to the right eye which has excellent vision, the patient’s left eye has poor vision, with persistent multiple ghost images and a reduced BCVA of 20/50 (MR=+0.75+1x80(Figure 1. A postoperative corneal topography showing a well centered hyperopic LASIK treatment ) Corneal topography of the left eye revealed the etiology of the problem. The steep region corresponding to the hyperopic treatment in the left eye appears to be inferiorly decentered.(Figure 2. The postoperative corneal topography of the contralateral eye of the same patient, showing an inferiorly decentered “second apex” created by hyperopic LASIK and the “first apex” (preexisting superiorly decentered corneal apex preop).
There appear to be double apices created by the superiorly off-centered naturally existing corneal apex (the upper apex) and the newly created inferiorly decentered second apex generated by the hyperopic LASIK. In contrast to a myopic treatment in which the corneal apex is flattened, a hyperopic treatment creates a new corneal apex.If the new apex is not in the same location as the existing corneal apex double apices can occur, which can create irregular astigmatism and reduce vision.This case demonstrates how corneal topography can play a critical role in revealing the etiology of poor visual quality after refractive surgery. The cause of loss of vision in the left eye of this patient is due to irregular astigmatism arising from an inferiorly decentered hyperopic LASIK treatment coupled with an existing superiorly off-centered corneal apex preoperatively
Posted by M Khanlari MD
Posted by at 08:49 PM
Increase A-scan Accuracy For Improved Outcomes
Review of ophthalmology jan 2003
This article reviews how accurate biometry is now, more than ever, an important part of successful cataract surgery and offers some recommendations for those taking and reading the A-scans.The type of reading for which all biometrists should aim: Following the probe spike, there are five clear echo spikes of maximum height and descending orbital fat. Both peaks of the corneal spike are equally tall. The scleral spike is present. The rise of each echo is at a 90-degree angle to the baseline. The only absolutely accurate axial length measurement is going to be through a non-contact technique. That’s either immersion with one of the shells, be that Prager or Hansen, or with Zeiss’ IOLMaster on eyes that do not have dense cat-aracts or other media opacity.”The sound beam is directed at an angle through the lens rather than through the center of both the front and back surfaces. When the beam is not going through the center of the lens, it is not on the visual axis or the center of the macula. Experience Is King.Though a reliable machine with the features needed to obtain a high level of accuracy is a good starting point, the user must have a good technique to match it..The use of the B-scan to confirm the axial length of a questionable A-scan will greatly improve your accuracy
Common Mistakes
One common error is the corneal compression inherent to the contact technique. While you are taking the reading, monitor the anterior chamber depth on your screen. You’ll be able to tell which has the most indentation. “If you see a 3.5 mm vs. a 3.3 mm, you know you have indented more on the one reading 3.3 mm. The deeper the anterior chamber depth the better,” Another common mistake is not seeing a perfectly straight retinal spike. There should be a 90-degree rise at the bottom. “A nice straight vertical line,” . Not seeing that means you’re not perpendicular or there is macular pathology to cause it. Another alignment mistake occurs if the beam is aligned along the optic nerve and not the macula. “If the scleral spike is absent,” , “You are on the optic nerve.”“Too many technicians are taught to look for four echo spikes instead of five. This is wrong,”. “You can fix this by tilting to aim the sound beam more temporally.”
Posted by M Khanlari MD
Posted by at 08:14 PM
Smoke Affects Tear Protein
Graefe’s Arch Clin Exp Ophthalmol 2002;240: 889-892
Ischemic, toxic and oxid-ative effects of cigarettes are thought to play an important role in damaging ocular tissue. Changes in tear protein patterns of smokers in comparison to nonsmokers are correlated with an increase in dry-eye-related subjective symptoms in smokers, according to a new German study.Research at the Department of Ophthalmology at the University of Mainz analyzed and compared electrophoretic patterns in tears of 29 smokers, 26 severe smokers and 50 nonsmokers. Each patient was asked for subjective symptoms such as burning, itching, and foreign-body sensation. Tear proteins were separated by gel electrophoresis and digital image analysis was performed.ear protein patterns in smokers (P<0.05) and severe smokers (P<0.05) were different from those of nonsmokers. There were significantly more protein peaks in the severe smokers group (P<0.005) than in nonsmokers.
Posted by M Khanlari MD
Posted by at 07:36 PM
Onchocerciasis campaign ends successfully
OCULAR SURGERY NEWS 1/15/03
OUAGADOUGOU, Burkina Faso – After nearly 30 years of work to eliminate river blindness in West Africa, the World Health Organization’s Onchocerciasis Control Programme (OCP) ended Dec. 6. The campaign was launched to eliminate river blindness as a public health hazard. It was also designed to assist countries in West Africa to develop a system of monitoring and preventing river blindness and other diseases.OCP initially began with control programs to eliminate the black fly. Efforts included spraying 1.3 million square kilometers with larvicide. Volunteers also collected and monitored flies.When the program began in 1974, almost 10% of the population was completely blind, and 30% had severe vision problems. Two hundred and fifty thousand kilometers of river valley farmland had been abandoned – an economic loss of $30 million a year.In 1988, Merck donated invermectin, an anti-parasite drug. Volunteers drove annually to remote locations to distribute the pills until the communities took over this portion of the program.Now, 28 years later, volunteers are estimated to have prevented 600,000 cases of river blindness and have enabled farmers to return to the 25 million hectares of fertile land along the rivers in that area. This is enough land to grow food for 17 million people, officials said.
Posted by M Khanlari MD
Posted by at 06:08 PM
Addition Technology to expand INTACS in Europe
OSN
FREMONT, Calif. – Addition Technology Inc. received CE marking for six additional Intrastromal Corneal Ring Segments sizes, doubling its INTACS product line in Europe.
The new sizes of INTACS provide both smaller increments of correction within the range of –1 to –5 D of myopia, and new sizes to expand the range to –0.5 to –5 D.In Europe, INTACS are approved for patients with –0.5 D to –5 D of myopia and 1 D or less of astigmatism. In the United States, the inserts are approved for –1 D to –3 D with 1 D or less of astigmatism.
Posted by M Khanlari MD
Posted by at 05:48 PM
Chronic relapsing inflammatory optic neuropathy (CRION)
Brain, Vol. 126, No. 2, 276-284, February 2003
We describe the clinical characteristics and early natural history of a form of inflammatory optic neuropathy which is frequently bilateral and often painful, and is characterized by relapses and remissions. MRI scans of the brain are normal and those of the optic nerves often, but not always, show high signal abnormalities which enhance. The symptoms and signs respond well to corticosteroid treatment, although long-term immuno suppression is often necessary. The syndrome behaves in a way which is typical of the condition known as granulomatous optic neuropathy, but during a median follow-up of 8 (2–26) years in no case has evidence for systemic sarcoidosis been identified. We suggest that the disorder be named chronic relapsing inflammatory optic neuropathy (CRION)
Posted by M Khanlari MD.
Posted by at 05:34 PM
January 22, 2003
ORAL ANTIOXIDANT SUPPLEMENTATION IN DIABETIC PATIENTS PREVENTS OCULAR SURFACE DISEASE
BJO dec 2002
Diabetes mellitus is regrettably associated with a number of ocular complications. Ocular surface manifestations in diabetics have been a subject of increased interest over the past few years. Sitaras and colleagues present the findings of 50 patients with non-insulin dependent diabetes who were given vitamin C (100 mg/day) and vitamin E (400 IU/day) for 10 days. Nitrite levels were found to be significantly reduced after 10 days of vitamin C and E supplementation. Moreover, improved values for the Schirmer test and increased goblet cell density were also demonstrated. The authors suggest that oxidative stress and free radical production that is known to be associated with diabetes can be inhibited by vitamin C and E supplementation. This in turn reduces the oxidative damage produced by nitric oxide and other free radicals and thus improves the ocular surface disorders associated with diabetes. See more ...
Posted by M.Tabrizi MD
Posted by mtmdop at 12:40 AM
Botulinum toxin A treatment in patients suffering from blepharospasm and dry eye
BJO Jan 2003
Many patients with essential blepharospasm also show dry eye signs and symptoms. Botulinum toxin A is an effective treatment for reducing spasms in these patients. In this investigation, the effect of botulinum toxin A injections on tear function and on the morphology of the ocular surface in patients suffering from blepharospasm in combination with a dry eye syndrome was investigated.
Method: Botulinum toxin A injections were applied to 16 patients with blepharospasm. All patients complained of dry eye symptoms and had reduced tear break up time values.
Results: Although all patients were relieved of blepharospasm after botulinum toxin injections, only three noticed an improvement in dry eye symptoms. Eight patients noticed no difference and five complained of worsening.
Conclusion: In the patients presented here suffering from blepharospasm and dry eye, botulinum toxin A injections were effective in relieving blepharospasm but were not successful in treating dry eye syndrome.
Posted by M.Tabrizi M.D
Posted by mtmdop at 12:18 AM
January 21, 2003
Increasing the levels of antioxidants in the retina might influence macular function in early age-related maculopathy
OSN-RETINA TOP STORIES 1/13/03
A study in ROME compared changes in the retinal function of early age-related maculopathy patients with normal age-matched controls after short-term antioxidant supplementation. They divided 30 patients with early age-related maculopathy (ARM) into two groups: one group received antioxidants and a second group received no antioxidants. Eight age-matched normal subjects were also divided into antioxidant and nonantioxidant groups.The antioxidant groups were given oral supplements of 15 mg of lutein, 20 mg of vitamin E and 18 mg of nicotinamide daily for 180 days. Eight of the 17 patients in the ARM/antioxidant group took supplements for an additional 6-month period. At the 6-month follow-up, the focal electroretinograms of all patients on antioxidants were increased in amplitude compared with baseline values; no significant changes were found in the nonantioxidant groups. Patients who took the antioxidants for the additional 6 months had increased focal electroretinograms with respect to baseline at 1 year, but not different from those recorded at the 6 month mark. In patients who discontinued antioxidant use after 6 months, the focal electroretinogram amplitude decreased to levels close to baseline. In the ARM antioxidant group, visual acuity increased at 6 months in three patients and remained stable in 13. Visual acuity remained unchanged for patients with AMD who were not on antioxidants. The study authors note that these results do not provide evidence of long-term benefit of antioxidant use in patients with AMD. “Nevertheless, these data suggest that oral antioxidant supplementation may induce a short-term, significant improvement of retinal function in early ARM.
Posted by,K.H.Jalali,MD. Edited by M Khhanlari,MD
Posted by kjalali at 11:14 PM
Diplopia after encircling procedure for retinal detachment
Spektrum der Augenheilkunde
Conclusion: Avoiding unnecessary preparation of the muscles when placing the encircling band without destroying of tenon and periorbital tissue, motility exercises after the operation and full refractive correction for sensory compensation of deviations as early as possible is recommended as well as antiphlogistic drugs to avoid scarring and treatment with prism. Removing of the encircling band does not seem to improve the motility as the disorder is mainly caused by hypertrophic scarring, neither does Mitomycin C or the application of viscoelastic substances
Posted by M Khanlari MD
Posted by at 10:19 PM
STAAR Toric ICL receives European marketing approval
OCULAR SURGERY NEWS 1/15/03
LONDON — The European Agency for the Evaluation of Medical Products has granted marketing approval for the toric version of the Implantable Contact Lens. The Toric ICL uses the same lens design as the spherical ICL, but employs a toric optic for correction of astigmatism.Ms. Smith explained that safety and efficacy for the spherical ICL has been well demonstrated in previous trials and the company only needed to demonstrate rotational stability for the toric version.Rotational stability wasdemonstrated through evaluation of a series of slit lamp photographs taken on postoperative day 1 and at 3 months, 6 months and 1 year.Both the spherical ICL and the toric version remain in clinical trials in the United States. The spherical ICL completed enrollment in November 1999, and the company expects to submit its pre-market approval application to the United States Food and Drug Administration shortly.“The fact that it received the CE mark is a milestone for this product,” John A. Vukich, MD, the medical monitor for all U.S. clinical trials of the ICL, told Ocular Surgery News. “The fact that it is able to correct virtually all refractive errors really makes it a robust option for patients who previously may not have benefited from refractive surgery.”
Posted by M Khanlari MD
Posted by at 10:13 PM
[1/21/2003 9:05:PM | Alireza Habibollahi]
CK providing good patient satisfaction
JRS
Almost all patients treated with conductive keratoplasty are satisfied with their vision postoperatively, according to Refractec. The company announced results of a post-market survey here at the joint meeting of the American Academy of Ophthalmology and Pan-American Association of Ophthalmology.
Between the April 2002 Food and Drug Administration approval of conductive keratoplasty (CK) and the first week of October, surgeons performed close to 4,000 CK procedures. According to Refractec’s press release “nearly 95% of patients reported being ‘satisfied’ to ‘extremely satisfied’ with their visual outcome post-CK.”
Refractec purposely limited distribution of the technology to a controlled number of surgeons in order to manage the post-launch data and to “ensure the successful implementation of this new technology by physicians,” according to the company. Only 54 U.S. surgeons were trained in and given access to the technology.
“The demand for CK has grown at a very rapid pace, compared to past vision correction procedures,” said Mitchell B. Campbell, president and chief executive officer of Refractec, in the press release.
CK is approved for use in the United States for the temporary reduction of spherical hyperopia in patients who have a cycloplegic spherical equivalent refraction of +0.75 D to +3 D and 0.75 D or less of astigmatism.
Posted by A Habibollahi.
Posted by at 10:12 PM
Vitreoretinal Surgery Enters Near Era?
Less surgical trauma and more rapid recovery
review of ophthalmology
Since the advent of pars plana vitrectomy in the 1970s, technological advances in instrument design and surgical techniques have resulted in better outcomes for patients and streamlined operating procedures. One need only talk to operating room personnel who vividly remember the six- to eight-hour vitrectomy procedures of the ’70s or ’80s to realize that things have certainly changed for the better.
The 25-ga. transconjunctival vitrectomy system (Bausch & Lomb, 25-TVS) appears to be the next evolutionary step in vitreoretinal surgery. This system was designed through a coordinated effort between the Microsurgical Advanced Design Lab (MADLAB, now located at the Doheny Retina Institute) and Bausch & Lomb. A 25-ga. transconjunctival cannula system permits rapid entry into the eye without extensive conjunctival dissection. The sclerotomies are reduced in diameter from 1.0 mm to 0.5 mm, creating self-sealing incisions and eliminating the need for scleral suturing at the completion of surgery.
Posted by M.Miraftab MD,
Posted by mmiraftab at 05:35 PM
1/21/2003 7:26 AM | Alireza Habibollahi]
Lasik for Recurrent Hyperopia Following Laser Thermal Keratoplasty
j R S Vol. 16 No. 2 March/April 2000
Laser thermal keratoplasty (LTK) has its main indication in the correction of hyperopia. However, regression of refractive effect following LTK is a limitation. LASIK may provide a good alternative to correct residual refractive errors.
Fifty hyperopic eyes with varying amounts of regression after LTK underwent LASIK. The Chiron Automated Corneal Shaper microkeratome was used to make aMean flap of 160 µm and laser ablation was performed with the Technolas 217 Planoscan excimer laser. Postoperative follow-up was 6 months.RESULTS:
spherical equivalent refraction improved from +2.92 ± 1.60 D to +0.36 ± 1.48 D. Mean best spectacle-corrected visual acuity changed from 0.78 ± 0.14 before LASIK to 0.76 ± 0.16 D 6 months after LASIK. Mean uncorrected visual acuity changed from 0.37 ± 0.16 to 0.66 ± 0.24. Forty-two percent (21 eyes) were within ±0.50 D of intended correction, 60% (30 eyes) were within ±1.00 D, and 76% (38 eyes) were within ±2.00 D. After LASIK, confluent haze between previous LTK spots was observed in most eyes, as LASIK ablation took place at the sites of the LTK spots.CONCLUSION
LASIK after LTK is a good alternative for hyperopic regression. Predictability and efficacy are less than with primary LASIK for hyperopia, but the procedure is equally safe.
posted by A Habibollahi M.D
Posted by at 07:43 AM
Mechanical endonasal dacryocystorhinostomy with mucosal flaps
B.J.O, January, 2003
A prospective series of 104 consecutive endonasal DCRs performed . The technique involved anastomosis of nasal mucosal and lacrimal sac flaps and a large bony ostium. This procedure involves creation of a large ostium and mucosal preservation for the construction of flaps. The anatomical success was 95% and similar to external DCR and better then other endonasal approaches. The authors suggest that creation of a large ostium as well as mucosal flaps improves the efficacy of this endonasal technique.
Posted by A Farahi M.D
Posted by afarahi at 12:18 AM
Endonasal dacryocystorhinostomy with mucosal flaps
AJO , January, 2003
A prospective series of 44 consecutive endonasal DCRs performed . The new technique involved creation of a large bony ostium and mucosal flaps to create an anastamosis between the lacrimal sac mucosa and nasal mucosa. Its anatomic success rate (91% or 40 of 44 DCRs) compares favorably with the success rate of other techniques for endonasal DCR and is also similar to the success of external DCR. .
Posted by A Farahi M.D
Posted by afarahi at 12:06 AM
January 20, 2003
Factors for Glaucoma Progression and the Effect of Treatment (The Early Manifest Glaucoma Trial)
Arch Ophthalmol. 2003;121:48-56
To assess factors for progression in the Early Manifest Glaucoma Trial (EMGT), including the effect of EMGT treatment.
Two hundred fifty-five open-angle glaucoma patients randomized to argon laser trabeculoplasty plus topical betaxolol or no immediate treatment (129 treated; 126 controls) and followed up every 3 month. Patients treated in the EMGT had half of the progression risk of control patients. The magnitude of initial IOP reduction was a major factor influencing outcome. Progression was also increased with higher baseline IOP, exfoliation, bilateral disease, worse mean deviation, and older age, as well as frequent disc hemorrhages during follow-up. Each higher (or lower) millimeter of mercury of IOP on follow-up was associated with an approximate 10% increased (or decreased) risk of progression.
Posted by M.Miraftab MD,
Posted by mmiraftab at 11:08 PM
Mitomycin safe, effective for conjunctival, cornea squamous cell carcinoma
OSN,July,2002
Topical mitomycin C was a safe and effective therapy for conjunctival and corneal squamous cell carcinoma in a study here, even for extensive recurrent tumors. With applications of the antimetabolite, all tumors showed complete regression with no recurrence during the study period. Carol Shields and others here at Wills Eye Hospital conducted a prospective study on 10 eyes of 10 patients with extensive recurrent conjunctival and corneal squamous cell carcinoma. The patients received one drop of topical MMC 0.04% four times daily in the eye with the carcinoma. Treatment cycles were 1 week with medication, 1 week without. This was repeated until resolution of the malignancy was seen.
After one to four cycles of medication, complete regression of the tumor was reported in all patients, leaving normal appearing epithelial surfaces. MMC-related side effects were transient, including conjunctival erythema and chemosis and punctate epithelial keratopathy. No long-term complications were seen.
Posted by:Sh.Ebadollahi M.D.
Posted by at 06:55 PM
ALT safe, effective as keratoconus treatment
OSN,November,2002
Automated lamellar keratoplasty is a simple and efficient treatment for keratoconus, according to Massimo Busin, M.D.
.He added that patients experience fast visual rehabilitation.
He said therapies for keratoconus in patients with normal corneal transparency are typically glasses, contact lenses or
conservative surgery, which he defines as epikeratophakia, intrastromal segment or perhaps an excimer laser procedure.
For keratoconus patients with scarred corneas, the appropriate therapy would be “Destructive surgery,” meaning penetrating keratoplasty or lamellar keratoplasty.Using lamellar keratoplasty for keratoconus, the surgeon can rebuild the normal curvature, replace the stromal scar and preserve the endothelium. “Microkeratome-assisted lamellar keratoplasty allows patients to achieve 20/20 vision as seen with LASIK,” Dr. Busin said. He qualifies patients as suitable for this procedure if they are spectacle- or contact lens-intolerant with scarring of the cone limited to the anterior half of the stroma. The technique is contraindicated in patients with corneas thinner than 380 µm or with opacities reaching the posterior half of the stroma, Dr. Busin said.
Posted by :Sh.Ebadollahi M.D.
Posted by at 06:35 PM
Intraocular pressure after intravitreal injection of triamcinolone acetonide
J B Jonas, I Kreissig and R Degenring
Department of Ophthalmology, Faculty of Clinical Medicine Mannheim of the University Heidelberg, Germany
To investigate the intraocular pressure (IOP) response after intravitreal injections of triamcinolone acetonide as treatment of intraocular neovascular or oedematous diseases.A prospective consecutive non-comparative interventional case series study included 71 patients (75 eyes) with progressive exudative age related macular degeneration (n = 64 eyes) or diffuse diabetic macular oedema (n = 11 eyes), who received an intravitreal injection of 25 mg triamcinolone acetonide. Mean follow up time was 6.86 (SD 2.52) months (range 3.1–14.47 months).
Results: IOP increased significantly (p<0.001) from 15.43 (3.26) mm Hg preoperatively to a mean maximum of 23.38 (8.37) mm Hg (range 13–64 mm Hg) postoperatively. An IOP rise to values higher than 21 mm Hg was observed in 39 (52%) eyes. Elevation of IOP occurred about 2 months after the injection. Preoperative predictive factor for the rise in IOP was younger age (p=0.013). It was statistically independent of refractive error, presence of diabetes mellitus, and indication for the injection.
Conclusions: After intravitreal injections of 25 mg of triamcinolone acetonide, an IOP elevation can develop in about 50% of eyes, starting about 1–2 months after the injection. In the vast majority, IOP can be normalised by topical medication, and returns to normal values without further medication about 6 months after the injection.
Posted by:M.Tabrizi
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Posted by mtmdop at 01:56 PM
HSV1 Latency Sites after Inoculation in the Lip: Assessment of their Localization and Connections to the Eye
Marc Labetoulle, Séverine Maillet, Stacey Efstathiou, Sybille Dezelee, Eric Frau and Florence Lafay
(Investigative Ophthalmology and Visual Science. 2003;44:217-225.)© 2003
LAT staining differed among structures: intense and widespread within trigeminal neurons, intermediate within the sympathetic intermediolateral cell group of the spinal cord and the facial motor nucleus, and weak in other sites. Long-term expression of LATs (positive at 180 and 720 days) was observed only in tissues where the staining was intense or intermediate at 28 dpi.
CONCLUSIONS. After inoculation into the upper lip of mice, HSV1 established latency in several nervous system structures that have direct or indirect connections with ocular tissues. These results suggest that after an oral primary infection, the most frequent in humans, HSV1 may establish latency in several sites connected to the eye and may finally result in herpetic ocular disease involving the cornea, the iris, or even the retina.
Posted by: S.Aliakbari
Posted by saliakbari at 09:43 AM
January 19, 2003
A 62-year-old female with blurry vision
Presenting History: The patient is a 62 year-old female who was referred to the ophthalmology service for recent onset of blurry vision. Upon further questioning the patient reported seeing "red" out of her left eye. Three days previously she had undergone a right-sided craniotomy with surgical clipping of a recently ruptured aneurysm at the tip of the basilar artery.
Previous ocular history: None
Past Medical History: Hypertension,Hyperthyroidism,Chronic Bronchitis,Gastritis
Medications: Dyazide; Atenolol; Prilosec; Estrace;Synthroid
Family and Social History: Non-contributory.
Visual Acuity: (uncorrected) OD 20/30 OS 20/200
Pupils: Normal (OU), no APD
Motility: Full (OU)
Tonometry: Normal (OU)
Slit Lamp Examination: Normal (OU)
Fundus Examination:
Posted by M khanlari MD
Posted by at 11:27 PM
Cornea 2003; 22(1):63-65
Surgical Treatment of Chronically Recurring Pterygium
Virender S. Sangwan, M.S.; Somasheila I. Murthy, M.D.; Aashish K. Bansal, M.S.; Gullapalli N. Rao, M.D.
To report the result of a combined surgical procedure of pterygium excision with simultaneous amniotic membrane transplant, conjunctival limbal autograft, and mitomycin C application in the management of two cases of chronically recurring pterygium.The two male patients, ages 24 and 42 years, had undergone six previous surgeries for pterygium, with and without adjunct procedures. In the follow-up period of 26 months for the first case and 25 months for the second case, no recurrence or complications were encountered.A combined procedure seems to be beneficial in cases of chronically recurring pterygia in younger patients. This approach may be considered when all other types of surgery have failed.
Posted by A R Naderi MD,
Posted by Ali Reza Naderi at 11:27 PM
Malignant glaucoma induced by a phakic posterior chamber intraocular lens for myopia
Laurent Kodjikian, MD, Philippe Gain, MD, PhD, David Donate, MD, Fre´de´ric Rouberol, MD, Carole Burillon, MD
A 23-year-old woman with −14.00 diopters of myopia requested emmetropia for professional reasons. An ICM 130 V2 myopic phakic intraocular lens (IOL) (Staar Surgical AG) was implanted in the posterior chamber. Three days later, the patient developed malignant glaucoma. Pupillary block glaucoma and choroidal hemorrhage or effusion were ruled out. As maximum medical treatment failed, rapid secondary surgery was performed with sclerotomy, aspiration in the midvitreous cavity, and removal of the IOL. The follow-up was 43 months.(j cataract refract surg 2002;28)
Posted by A R Naderi MD,
Posted by Ali Reza Naderi at 11:11 PM
Bilateral spontaneous subluxation of scleral-fixated intraocular lenses
Ehud I. Assia, MD, Arie Nemet, MD, Dani Sachs, MD
Two young men with primary ectopic lenses had intracapsular cataract extraction and scleral fixation of posterior chamber intraocular lenses (PC IOLs) using 10-0 polypropylene sutures tied to the IOL eyelets. Three to 9 years after implantation, spontaneous IOL vertical subluxation occurred in all 4 eyes (5 IOL loops), probably because of suture breakage. Late subluxation of a sutured IOL may occur several years after implantation. Double fixation and thicker sutures should be considered, especially in young patients..(j cataract refract surg 2002;28)
Posted by A R Naderi MD,
Posted by Ali Reza Naderi at 11:07 PM
Evaluation of the prophylactic use of mitomycin-C to inhibit haze formation after photorefractive keratectomy
Francesco Carones, MD, Luca Vigo, MD, Elena Scandola, MD, Letizia Vacchini, MD
The inclusion criteria were a spherical equivalent correction between −6.00 and −10.00 diopters (D) and inadequate corneal thickness to allow a LASIK procedure with a residual stromal thickness of more than 250 ěm. After PRK, the study group eyes were treated with a single intraoperative dose of mitomycin-C (0.2 mg/mL), applied topically with a soaked microsponge placed over the ablated area and maintained for 2 minutes. The control eyes did not receive this treatment. . No toxic or side effects were encountered postoperatively. No study group eye had a haze rate higher than 1 during the 6-month follow-up; 19 eyes (63%) in the control group did (P = .01).
The prophylactic use of a diluted mitomycin-C 0.02% solution applied intraoperatively in a single dose after PRK produced lower haze rates, better UCVA and BCVA results, and more accurate refractive outcomes than those achieved in the control group. J Cataract Refract Surg 2002; 28:2088–2095
Posted by A R Naderi MD,
Posted by Ali Reza Naderi at 10:48 PM
Posterior chamber intraocular lens supported by an intact vitreous face
Renuka Srinivasan, MS, Amjad Salman, MS, Pragya Parmar, MS, Deepak Sukumaran, DO, DNB
We describe a technique of posterior chamber intraocular lens (IOL) implantation in eyes with inadequate capsule support caused by inadvertent or planned intracapsular cataract extraction (ICCE) or in eyes having secondary IOL implantation after previous ICCE. The procedure is only performed in eyes with an intact anterior vitreous face, no vitreous prolapse into the anterior chamber, and no vitreous loss. The anterior vitreous is pushed back by viscoelastic material or air. The viscoelastic material is injected under the iris to create a free space between the iris and anterior vitreous. A single-piece, C-loop, poly(methyl methacrylate) IOL is slid onto the iris to rest on the anterior vitreous face; care is taken not to disturb the anterior vitreous. The technique was used in 15 eyes with a follow-up from 19 months to 5 years. All eyes had a stable IOL at each follow-up, and the visual acuity was 6/12 or better at the last follow-up.
J Cataract Refract Surg 2002; 28:2084–2087
Posted by A R Naderi MD,
Posted by Ali Reza Naderi at 10:31 PM
<i>Arteriolar pressure may predict progression to early glaucoma.January issue of Archives of Ophthalmology
MONTREAL — A measurement of arteriolar pressure can predict the progression from ocular hypertension to open-angle glaucoma, researchers here said. Measuring the low-end arteriolar pressure can provide an early, reproducible and physiological method to study vascular phenomena in glaucoma, the researchers said. more...
posted by A.Gholaminejad,MD
Posted by at 10:19 PM
Pathogenesis of the Vitreous Cloud Emanating From Subretinal Hemorrhage - Archives of Ophthalmology Ophtholinx,retina article Jan14 2003
Conclusion: Rapid necrosis of the retina occurs over thick subretinal hemorrhage and indicates the need for early displacement of the hemorrhage from the macula if function is to be preserved and breakthrough prevented...
posted by Riazi
Posted by at 12:19 AM
Case Report: Minocycline-Induced Ocular Pigmentation - Archives of Ophthalmology Ophtholinx retina articles,Jan 15 2003
Conclusion: Minocycline, a semisynthetic derivative of tetracycline, has anti-inflammatory properties that are used in the treatment of chronic inflammation. Deposition of minocycline has been reported in skin, nails, teeth, mucosa, thyroid, bones, and sclera. To the best of our knowledge, no cases of minocycline-induced retinal pigmentation have been reported. We believe that the unusual macular pigmentation in patient 2 is likely related to minocycline therapy. She had no other findings of age-related macular disease, nor was she using any other medications known to cause retinal pigmentation
posted by Riazi
Posted by at 12:14 AM
79 year-old female with redness and swelling of the left eyelids
what is diagnosis?
A 79 year-old female presented with redness and swelling of the lids of the left eye for 4 days. Little pain was present, but the patient reported the swelling continued to increase.The referring ophthalmologist noted proptosis of the left eye of 5 mm.
Past ocular history: non-contributory
Past medical history :medically controlled hypertension,no history of diabetes or allergies,mastectomy 17 years prior for carcinoma,appendectomy and hysterectomy 27 years prior
Meds:Briserin (i.e. Reserpin and Clopamid)
Vision: OD 20/30 OS 20/30
Pupils: Normal (OU), no APD
Motility: OD ortho, full; OS ortho; restriction on upwards gaze and downwards gaze with slight pain on eye movement in extreme upwards gaze
Posted by M Khanlari MD
Posted by at 12:08 AM
January 18, 2003
b> Transition to nonpenetrating trabecular surgery: sclerotrabeculectomy
J Cataract Refract Surg 2002,DEC
A transition from trabeculectomy to nonpenetrating trabecular surgery (NPTS) is proposed under the name of sclerotrabeculectomy. The technique, which is aimed at facilitating the transition to NPTS, is a modification of both penetrating and nonpenetrating techniques. Sclerotrabeculectomy uses a more superficial sclerokeratectomy than NPTS to avoid the risk of perforation. A minitrabeculectomy with cross-linked hyaluronate implant insertion in the sclerokeratectomy site is performed, with several sutures placed in the superficial flap.
posted by M. Pakravan
Posted by pakravanmd at 11:59 PM
Component upgrades make device a more versatile tool
Ophthalmology Times January 1, 2003
Orlando-Recent component upgrades, including a micro-suction ring and zero-compression heads, have made the Hansatome microkeratome (Bausch & Lomb) even easier, safer, and more predictable to use, "With the addition of these enhancements, there is good reason to see why the Hansatome is the market leader in the industry.The micro-suction ring facilitates flap creation in deep-set eyes and those with small fissures. It features a smaller footprint design than the standard suction ring, 19 versus 20.3 mm, and it is available in models that cut 8.5- or 9.5-mm diameter flaps. The micro-suction ring is a wonderful innovation, and Bausch & Lomb makes it very advantageous for Hansatome owners to upgrade to this component and it is a pleasure to use because it is very easy to apply and fits into much smaller fissures." The zero-compression microkeratome heads were designed to eliminate flap compression. They have improved consistency in flap thickness and reduced epithelial defect problems. It is available in 160-, 180- and 200-µm In preparing the field for the microkeratome procedureThis additional reduction in the suction level results in a much faster rise time and so decreases the likelihood of suction ring drift," Dr. Epstein explained. "However, the most important pearl for avoiding suction ring drift is to apply firm pressure to the suction ring before activation." Suction adequacy is evaluated by as-sessing three features-subjective loss of vision, pupillary dilation, and IOP measured with Barraquer tonometry. Dr. Epstein noted that most patients will not lose vision completely, but they should experience a significant diminution, and he will not proceed unless two of the three criteria are fulfilled.
Posted by M Khanlari MD
Posted by at 11:46 PM
Glaucoma drugs may pose risk to ocular surface
Ophthalmology Times January 1, 2003
Orlando-Ophthalmologists should be aware of the risks to the ocular surface associated with long-term use of glaucoma medications, according to Robert J. Noecker, MD, MBA. Corneal epithelial damage and conjunctival inflammation can occur from chronic use of glaucoma medications preserved with high concentrations of benzalkonium chloride (BAKDr. Noecker reviewed the results of a small animal study undertaken to determine the surface toxicity of some of the new glaucoma agents. The results were previously published in the July 15, 2002 issue of Ophthalmology Times, Page 6. He found dorzolamide HCl 2% b.i.d. (Trusopt, Merck) to produce the most damage to the corneal epithelium. Moderate damage was also seen in the rabbit eyes treated with latanoprost 0.005% (Xalatan, Pharmacia) once daily. Eyes treated with bimatoprost 0.03% q.d. (Lumigan, Allergan) and timolol maleate 0.5% b.i.d. (Timolol maleate, Falcon) had milder corneal damage. Brimonidine 0.15% b.i.d. (Alphagan P, Allergan) produced little damage to the cornea, Dr. Noecker said. The advantage of this medication is that it is preserved with the oxychloro complex Purite, which is very benign in low concentrations. "A non-BAK-containing drug like Alphagan P may be the drug of choice in patients with compromised ocular surfaces or a history of drug intolerance," he said.
Posted by M Khanlari MD
Posted by at 11:23 PM
FDA approves artificial cornea
Ophthalmology Times January 1, 2003
The FDA has approved what is said to be the first soft artificial cornea (AlphaCor, Argus Biomedical Pty. Ltd., Perth, Western Australia) for sale in the United States.
The keratoprosthesis is designed to replace a diseased or damaged cornea or failed human graft. It is made of a biocompatible, hydrogel polymer that eliminates the need for the immunosuppressant therapies usually required with human donor tissue. The artificial cornea, which looks like a clear donor corneal graft, has a visible spongy rim to which the patient's own cells attach to hold it in place and allow the eye to function normally.
Posted by M Khanlari MD
Posted by at 11:09 PM
Echobiometric Study of Ocular Growth in Patients With AmblyopiaJOURNAL OF PEDIATRIC OPHTHALMOLOGY & STRABISMUS Vol. 39 No. 4 July/August 2002
Carmen Burtolo, MD; Chiara Ciurlo, MD; Anna Polizzi, MD; Pasquale Bruno Lantieri, MD; Givanni Calabria, MD
The natural evolution toward emmetropia is governed by genetic factors, but experiments with animals have demonstrated that a feedback mechanism that depends on visual function may regulate ocular growth. We attempted to verify this hypothesis in school-age patients with amblyopia by observing the ocular growth and the refractive state in the fixating and nonfixating eye in myopia and hypermetropia. This situation simulates the animal model.We found a statistically significant increase in axial length in the fixating eye of patients with hypermetropia compared with the amblyopic eye (P = .0008). In patients with myopia, we found less of an increase in axial length in the fixating eye compared with the amblyopic eye (P = .0048). Good vision seems to influence the evolution of ocular growth toward emmetropization.
Posted by A R Naderi MD,
Posted by at 02:18 AM
Posterior Continuous Curvilinear Capsulorhexis With and Without Optic Capture of the Posterior Chamber Intraocular Lens in the Absence of Vitrectomy
JOURNAL OF PEDIATRIC OPHTHALMOLOGY & STRABISMUS Vol. 39 No. 5 September/October 2002
Usha K. Raina, MD, FRCS, FRCOphth; Vinita Gupta, MS; Ritu Arora, MD, DNB; D. K. Mehta, MS, MNAMS
Thirty-four eyes of 28 children with congenital or developmental cataract, aged 1.5 to 12 years (mean, 6.39 years), were included in this prospective, randomized study. Anterior continuous curvilinear capsulorhexis (ACCC) with PCCC without optic capture of the PC IOL was performed in group A (18 eyes) and ACCC with PCCC with optic capture of the PC IOL was performed in group B (16 eyes). None of the eyes underwent anterior vitrectomy. Secondary opacification of the visual axis, visual acuity, and possible complications were observed and analyzed. The follow-up period ranged from 8 to 28 months (mean, 17.5 months). All 16 eyes (100%) in group B had a clear visual axis at the end of follow-up. Eight eyes (44.4%) in group A had significant opacification of the visual axis. The difference between the two groups was statistically significant (P = .0011). No eye in group B required secondary intervention, whereas all 8 eyes in group A with significant secondary opacification required secondary intervention. There was no statistically significant difference in other complications such as anterior chamber reaction, fibrin formation, lenticular precipitates, and posterior synechiae. The final best-corrected visual acuity at the end of follow-up was comparable in the two groups (P > .05). PCCC with optic capture of the PC IOL prevents secondary opacification of the visual axis even in the absence of vitrectomy.
Posted by A R Naderi MD,
Posted by at 02:07 AM
Decreased Central Corneal Thickness in Children With Down Syndrome
JOURNAL OF PEDIATRIC OPHTHALMOLOGY & STRABISMUS Vol. 39 No. 5 September/October 2002
Cem Evereklioglu, MD; Kutluhan Yilmaz, MD; Necdet A. Bekir, MD
Central corneal thickness values were below 500 µm in 19 (67.8%) of the 28 children with Down syndrome, 4 of which were less than 450 µm. However, all central corneal thickness measurements in the control eyes were more than 500 µm. The mean central corneal thickness in the children with Down syndrome was significantly (P < .001) less (488.39 ± 39.87 µm) than that in the healthy control subjects (536.25 ± 20.70 µm). Mean keratometric values were significantly (P < .001) higher in the eyes of the children with Down syndrome (46.35 ± 1.28 D) than in the eyes of the control subjects (43.32 ± 1.15 D). Children with Down syndrome had a decreased central corneal thickness compared with healthy control subjects. Decreased central corneal thickness may give an artificially low intraocular pressure measurement by applanation tonometry. Central corneal thickness must be considered when developing approaches for keratorefractive treatment of patients with Down syndrome.
Posted by A R Naderi MD,
Posted by at 01:53 AM
Scleral Expansion Bands Show Modest Improvement In Presbyopia
American Journal of Ophthalmology (AJO®)
Scleral expansion bands modestly improve near vision in approximately half of presbyopic patients.Researchers in the United States enrolled 29 emmetropic, presbyopic patients, mean age 54 years. The study was non-randomised and non-masked. The authors implanted four polymethylmethacrylate segments in quadrantic scleral pockets in the dominant eye.Six months following the operation, accommodative amplitude increased by 1.7 and 1.5 diopters at 70 and 30 cm starting points respectively. Accommodative amplitude increased by 1.2 and 1.3 diopters respectively in the contralateral eyes. The authors concluded that scleral expansion bands modestly improved near vision in around half the patients with presbyopia. Moreover, the approach appears to be well tolerated.However, the authors commented that the improvement in near vision in the contralateral eye awaits explanation. The improvement might reflect a centrally controlled response or be an artefact, for example.
Posted by A R Naderi MD,
Posted by at 01:37 AM
January 17, 2003
Recommended diagnostic criteria for multiple sclerosis: guidelines from the International Panel on the diagnosis of multiple sclerosis.
Annals of Neurology 2001 Jul;50(1):121-7
The International Panel on MS Diagnosis presents revised diagnostic criteria for multiple sclerosis (MS). The focus remains on the objective demonstration of dissemination of lesions in both time and space. Magnetic resonance imaging is integrated with dinical and other paraclinical diagnostic methods. The revised criteria facilitate the diagnosis of MS in patients with a variety of presentations, including "monosymptomatic" disease suggestive of MS, disease with a typical relapsing-remitting course, and disease with insidious progression, without clear attacks and remissions. Previously used terms such as "clinically definite" and "probable MS" are no longer recommended. The outcome of a diagnostic evaluation is either MS, "possible MS" (for those at risk for MS, but for whom diagnostic evaluation is equivocal), or "not MS."
Posted by M.Miraftab MD,
Posted by mmiraftab at 05:06 PM
ARTISAN FORCEPS
ophthalmology management Dec 2002
Rhein Medical has added the Artisan Lens Holding Forceps to its catalog. The forceps let you fixate the implant and place the Artisan lens into the anterior chamber, aligning it precisely to the iris.The forceps come in two models, direct-acting and reverse-acting. The jaws of the direct-acting forceps close when the handles are compressed; the jaws of the reverse-acting forceps close when the handles are open. Both models grasp one haptic edge, which should give you firm control of the implant
Posted by M.Miraftab MD,
Posted by mmiraftab at 12:21 PM
The multifocal technique: a new era in clinical electrophysiology of vision
Focus springe 2002
Functional testing of vision has taken - is taking - a great leap forward with the introduction of the multifocal technique. Perhaps it is more accurate to say that conceptually the technique represents a great leap; its clinical application, through the multifocal electroretinogram (mfERG) and multifocal visual evoked potential (mFVEP), is better described as a steady series of small steps; But these are adding up to a very significant advance.
read more...
Posted by M.Miraftab MD,
Posted by mmiraftab at 01:33 AM
January 15, 2003
Dilation probing as primary treatment for congenital nasolacrimal duct obstruction
Journal of AAPOS,December,2002
Recent studies have suggested that maximally enlarging the passage through the NLD system may enhance the success of simple NLD probing. This study used sequential probing with modified, taper-tip probes to evaluate whether maximally enlarging the nasolacrimal duct can effectively treat congenital NLD obstructions in all age groups. Sequential NLD probing was successful in 66 (92%) of 72 eyes. The authors concluded that this method has a high rate of success in all children. Age does not appear to have an impact on success of probing.
Posted by A.Farahi MD,
Posted by afarahi at 12:16 AM
January 14, 2003
Wavefront analysis has an expanding role in diagnosis
Early results are promising for this emerging technology, which may one day become a standard diagnostic tool.
Wavefront analysis has become a key part of the ophthalmic lexicon. Many of us are now taking a closer look at this emerging technology and gaining a better understanding of how it can serve our patients. Here at Minnesota Eye Consultants, we have had the opportunity to work with the Visx WaveScan. In addition to the potential for improving LASIK outcomes, this technology can provide practitioners with valuable insight to aid on the diagnostic front.
Wavefront analysis has already assisted us with numerous diagnostic dilemmas, proving helpful with patients who have come in with symptoms of unknown cause. We further believe that wavefront also holds great promise in the therapeutic area, for helping us to bring patients whose acuity has suffered as a result of early refractive surgery back up to visual par and beyond.
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Reposted by M,Taherzadeh MD
Posted by at 11:08 PM
Glistenings found in seven IOL types
OSN,Jan,2003
TRIESTE, Italy — Glistening formations were found in seven different types of foldable IOL in a study here. IOL composition did not play a significant role, according to the randomized study. Patients implanted with the AcrySof acrylic IOL had a higher percentage and a greater density of glistenings, . But all glistenings seen in the study were described as trace to moderate, and did not observe glistening density severe enough to impair visual acuity in any IOL. Daniele Tognetto, MD, and colleagues randomized 273 patients to have one of seven types of foldable IOLs implanted in the capsular bag following phacoemulsification. Thirty-nine patients received the CeeOn Edge 911A (Pharmacia), 36 received the ACR6D (Corneal), 41 patients received the AcrySof (Alcon), 45 received the SI-40NB (AMO), 36 received the Hydroview H60M (Storz), 42 received the Sensar (AMO) and 34 received the Stabibag (IOLTech).Patients were examined at intervals out to 2 years postoperative. Best corrected visual acuity (BCVA) was measured at all follow-up points, as were the presence and grade of glistenings. All IOLs showed glistenings. The percentage of patients with glistenings increased up to 90 days postop and then stabilized in all groups except the AcrySof group, which had a continuous increase of glistenings over the entire follow-up period. The type of IOL “seems to have a significant effect on glistenings. At the 2-year mark, the percentage of patients with glistenings ranged from 40% in the Sensar group to 67.5% in the AcrySof group. The AcrySof group had the highest percentage of IOLs with glistenings and the highest grade of glistenings at the last three exams. “We noted glistenings were aligned in the direction of the folding axis in some cases. We do not discard the possibility that the mechanical stress of folding maneuvers could play a part in the development of glistenings,” Dr. Tognetto wrote.
posted by M,Taherzadeh MD
Posted by at 10:59 PM
Diabetic patients have poorer phaco outcomes than nondiabetics
OSN
GALVESTON, Texas — Diabetic patients have worse visual outcomes after small-incision phacoemulsification surgery than nondiabetics, according to a study here. Visual acuities of diabetic patients were improved by the cataract surgery, but not as much as in nondiabetic patients.The study authors suggest that, given an inverse association between preop levels of retinopathy and visual outcome, it may be best to perform cataract surgery while the patient is in early stages of retinopathy. Researchers at the University of Texas here retrospectively reviewed the charts of 106 patients with diabetes and 55 patients without who underwent small-incision phaco. Age, sex, preoperative best corrected visual acuity (BCVA) and visual potential were comparable in the two groups. At 1 year, BCVA was 20/40 in 82% of the diabetic group and in 95% of the control group (P = .01). Coexisting diabetes and preoperative levels of retinopathy were the most important factors affecting postop BCVA. At 4 years, patients with diabetes were less likely than control patients to achieve a BCVA better than or equal to the preop visual potential (P = .011). Patients with nonproliferative diabetic retinopathy were nearly five times less likely to achieve a postop BCVA of 20/40 than patients with diabetes but no retinopathy. Patients with proliferative diabetic retinopathy were 30 times less likely (P < .0001) to achieve a BCVA of 20/40 than patients with diabetes but no retinopathy.
The study is published in the August issue of Journal of Cataract & Refractive Surgery.
posted by M,Taherzadeh MD
Posted by at 10:50 PM
Fragmentation effective for white cataracts
OSN
THOROFARE, N.J. — Phacofragmentation is a viable option to phacoemulsification, especially in developing countries, said Istiantoro Soekardi, MD. While phacoemulsification is ideal for cataract surgery in developed countries, it is not appropriate in all areas of the world, he said. “It is an expensive, complex and formidable machine, which has a long learning curve and is not readily available in developing countries,” Dr. Istiantoro said. His practice is based in Jakarta, Indonesia. In phacofragmentation, the nucleus is divided into small fragments and then manually removed from the anterior chamber, Dr. Istiantoro said. The surgery is especially suited for the hard cataracts often seen in developing countries, he added. In a prospective randomized study, Dr. Istiantoro divided 32 eyes into two equal groups, one undergoing phacoemulsification and the other phacofragmentation, to determine the procedures’ efficacy and safety in removal of mature white cataracts. Postoperatively, the mean pupil diameter after IOL insertion was 7.72 mm in the phacofragmentation group and 7.82 mm in the phacoemulsification group. Mean corneal thickness at day 1 was 872 µm in the fragmentation group and 647 µm in the emulsification group. At day 1, the emulsification group demonstrated better uncorrected visual acuity, but at 1 week and 1 month the groups showed no significant differences, he said.
posted by M,Taherzadeh MD
Posted by at 10:42 PM
Changes in the tear proteins of diabetic patients
BMC Opthomology
The tear protein patterns of diabetic patients are very different in the number and intensity of spots from those of healthy subjects. Furthermore, it could be demonstrated that the differences found in the tear patterns of diabetic patients are not equal to those found in previous studies in patients suffering from dry-eye disease. The alterations in the diabetic tears were correlated with the duration of the diabetic disease. With longer disease, history changes in the tear protein patterns increased. With the course of the disease some protein peaks appeared that are not present in healthy persons. Our study shows that the analysis of electrophoretic tear protein patterns is a new non-invasive approach in the early diagnosis and analysis of the pathogenesis of diabetes induced ocular surface disease.
Posted by M Khanlari Md
Posted by at 10:39 PM
Capsular ‘shrink-wrap’ faster with silicone IOLs than acrylic
OSN
FUKUOKA, Japan — Silicone IOL optics are completely apposed by the anterior and posterior capsules more quickly than acrylic IOL optics, according to a clinical study here. Silicone IOLs took about 8 days to complete capsular contact while acrylic IOLs took about 11 days. The difference was statistically significant. Researchers here randomized 32 patients scheduled to undergo phacoemulsification to either silicone or acrylic IOL implantation. Contact of the anterior and posterior lens capsule with the IOL optic surface was evaluated using Scheimpflug photography at days 3, 5, 7, 9, 11, 14, 21 and 28 postoperatively. Anterior chamber depth was measured, and the day each capsule was completely apposed to the IOL optic was noted. The anterior capsule was in contact with the IOL optic on the same day or earlier than the posterior capsule in all patients. Complete apposition of the IOLs was achieved earlier with silicone than with acrylic by both the anterior capsules (P < .0001) and the posterior capsules (P = .0339). No significant change in mean anterior chamber depth was observed with the silicone IOLs. Significant anterior shift was noted with the acrylic IOLs.
The study is published in the August issue of Ophthalmology.
posted by M,Taherzadeh MD
Posted by at 10:38 PM
Phaco, laser, lens technologies now allow ultrasmall cataract incisions, speakers say
OSN,Jan, 2003
NICE, France — Advances in IOL and cataract removal technologies can enable surgeons today to complete cataract surgery through incisions as small as 1 mm.
Certain IOLs such as the rollable IOL made by Acri.Tec can be inserted through these ultrasmall incisions, eliminating the need to widen the incision for lens implantation.
With the WhiteStar technology (AMO), the normally uninterrupted ultrasound is broken into bursts of energy alternating with rest periods. “The technology allows for very rapid cooling” of ocular tissues. Mini-incision phaco can also be safely performed using an anterior chamber maintainer as the sole fluid source.“Returning to laser cataract surgery, Carlos Vergés, MD, PhD, said the technology “is not safe for all types of cataracts.” He advised surgeons to continue to use ultrasound on hard cataracts. Current laser-phaco technology uses more energy with harder cataracts, which could lead to complications. “It's an urban myth that laser cataract surgery is a slow procedure,” Dr. Dodick said. He noted that Wolfram Wehner, MD, of Nuremburg, Germany, has reported using the Dodick laser technology in 849 cataract cases in which "skin to skin time is under 10 minutes." Dr. Dodick said recent modifications to his laser cataract removal system are “resulting in greater vacuum creation.” The modified tubing he now uses for IOL implantation is currently in beta testing, and he expects the tubing to be available in the first quarter of 2003.
posted by M,Taherzadeh MD
Posted by at 10:30 PM
Use NSAIDs Carefully to Avoid Corneal Complications
Eyenet,June,2002
Ophthalmologists have used NSAIDs to treat ocular allergies, control pain and photophobia after refractive surgery, prevent miosis in cataract surgery, and reduce inflammation and treat (or prevent) cystoid macular edema after cataract surgery.But a number of corneal complications are now linked to NSAID use, including superficial punctate keratitis, erosions, sterile ulcers, melts and perforations. Corneal side effects have been associated with all ocular NSAIDs, including generic diclofenac, proprietary diclofenac (Voltaren) and ketorolac (Acular).The largest number of severe problems occurred with generic diclofenac, which was pulled off the market in 2000. Although current NSAIDs are probably safer than generic diclofenac, they still can cause trouble when they’re not used properly.A recent Japanese study explored some biochemical effects from 0.1 percent diclofenac sodium solution. The drops were instilled in 10 eyes of 10 healthy patients three times daily for two weeks. The researchers took tear samples before, during and after drug treatment and measured concentrations of prostaglandin E2 and substance P in tears using enzyme immunoassays.They found that diclofenac sodium eye drops concurrently reduced concentrations of prostaglandin E2 and substance P in tears, and they concluded that depletion of substance P by diclofenac sodium may promote the development of corneal complications
Posted by:Sh.Ebadollahi.M.D.
Posted by at 12:54 AM
January 13, 2003
Treatment for retinal dystrophies near fruition
Eurotimes,Jan ,2003
Several biological approaches have shown great promise in recent years in animal trials in the treatment of retinal disorders similar to retinitis pigmentosa in humans. The new treatment strategies include the use of growth factors, gene therapy and retinal transplantation. Human trials with these new forms of therapy are likely to begin within a few years.“Many patients who attend low-vision clinics are no longer seeing ophthalmologists. With the prospect of treatment, it perhaps would be appropriate to recycle such patients into ophthalmic practice so they can be studied, their disease characterised and the causative genes identified. That way, when treatments become available in four to six years that patient population is known to the clinician and appropriate patients can be recruited,” Dr Bird pointed out.
posted by,K.H.Jalali,MD.
Posted by kjalali at 06:38 AM
Retinal vascular anomalous complex can be treated successfully
OSN January 12, 2003
Retinal vascular anomalous complex can be treated successfully, especially if an early diagnosis is made.Retinal vascular anomalous complex (RVAC) is a recently described retinal condition. It shares some characteristics with age-related macular degeneration, but RVAC is usually poorly responsive to the standard treatments administered for AMD. Photodynamic therapy can offer some benefits. If discovered during the initial phases of the disease, direct photocoagulation offers even more benefits to patients. Transpupillary thermotherapy has also shown some encouraging results.
.
posted by,K.H.JALALI,MD.
Posted by kjalali at 05:51 AM
Mismatch between flap and stromal areas after laser in situ keratomileusis as source of flap striae
To calculate theoretically the magnitude of the excess area between the lower surface of the flap and the underlying ablated stroma.On the initial assumptions of a nonextensible flap and a spherical cornea, flap and ablated stromal areas were determined as a function of myopic correction in the range of 0 to -12 diopters (D) for typical values of corneal radius (7.8 mm) and flap thickness (160 m), together with a range of ablation zone diameters (4.0 mm, 6.0 mm, 8.0 mm, and 10.0 mm).Excess flap area increases with the magnitude of the refractive correction and the diameter of the ablated zone. For a -6.0 D correction and an 8.0 mm ablation zone, the excess area is nominally about 1.0 mm2, giving a potential overlap of the flap at the edge opposite the hinge of about 100 m.Excess flap area may cause striae because of wrinkling. Although a nonextensible flap is assumed in the model, any stretching or contraction due to cutting the flap will be independent of the refractive correction. Hence, a mismatch in areas must still occur. This geometric effect may have clinical consequences in optical aberration, refractive regression, or impaired wound healing.
Posted by A R Naderi MD,
Posted by at 04:58 AM
Repeatability and validity of Zywave aberrometer measurements
To study the repeatability of Zywave aberrometer (Bausch & Lomb) measurements and compare the measurements with those of subjective refraction and noncycloplegic and cycloplegic autorefractions in a clinical setting.Subjective refraction measurements are slightly more myopic than cycloplegic autorefraction measurements. With a dilated pupil, the Zywave measurements were significantly more myopic than subjective refractions and even more myopic than cycloplegic autorefractions. Zywave measurements and subjective refractions were in better agreement with a 3.5 mm pupil. The repeatability of Zywave aberrometer measurements is adequate for lower-order aberrations.
Posted by A R Naderi
Posted by at 04:47 AM
Retinal nerve fiber layer thickness changes after an acute increase in intraocular pressure
OSN
To determine whether the increase in intraocular pressure (IOP) for 45 seconds during laser in situ keratomileusis (LASIK) suction can induce a decrease in retinal nerve fiber layer thickness (RNFLT) assessed by a confocal scanning laser polarimeter.Before compression, the mean RNFLT was 69.09 m ± 10.96 (SD); it was 69.27 ± 10.98 m after 2 minutes and 67.00 ± 10.58 m after 1 month. No statistically significant difference was found between the before and after measurements.A 45-second acute increase in IOP, such as during LASIK suction, did not decrease the RNFLT in normal eyes.
Psted by A R Naderi MD,
Posted by at 04:34 AM
Imperfect optics may be the eye’s defence against chromatic blur
James S. McLellan, Susana Marcos, Pedro M. Prieto & Stephen A. Burns*
The optics of the eye cause different wavelengths of light to be differentially focused at the retina. This phenomenon is due to longitudinal chromatic aberration, a wavelength-dependent change in refractive power. Retinal image quality may consequently vary for the different classes of cone photoreceptors, cells tuned to absorb bands of different wavelengths. For instance, it has been assumed that when the eye is focused for mid-spectral wavelengths near the peak sensitivities of long- (L) and middle-(M) wavelength-sensitive cones, short-wavelength (bluish) light is so blurred that it cannot contribute to and may even impair spatial vision. These optical effects have been proposed to explain the function of the macular pigment, which selectively absorbs short-wavelength light, and the sparsity of short-wavelength-sensitive (S) cones. However, such explanations have ignored the effect of monochromatic wave aberrations present in real eyes.
Posted by M.Miraftab
Posted by mmiraftab at 01:20 AM
January 12, 2003
Disposable microkeratomes address infection control concerns
Eyeworld,Jan 2003
Disposable microkeratomes are gaining popularity in Europe, where sterilization regulations have become increasingly strict, due in part to Mad Cow disease (bovine
spongiform encephalopathy). When sterilization is an issue, ophthalmologists have found that disposable microkeratomes save them time and money.Disposable microkeratomes, of which there are now four on the market, might have been a less expensive and timesaving alternative.One of the main advantages of a disposable microkeratome is related to sterility. Because the system is already set up, there is a very low probability of technician or mechanical set-up error. Additionally, disposable microkeratomes eliminate the buildup of debris and potential stimulants for diffuse lamellar keratitis.Another advantage of disposable microkeratomes is cost. “The price per eye for just the disposable components of standard microkeratomes (blade and tubing) is $55 to $75. Then, add the cost of the unit, which is about $45,000-$60,000, and divide it by the number of procedures to get the current per-eye cost. “Many ophthalmic surgeons prefer automated microkeratomes, as the consistent speed results in better predictability in flap thickness,” Stevens said. “However, those familiar with using manual instruments will be comfortable using the manual disposables,”.
posted by M.Taheri MD
Posted by at 11:42 PM
Refractive surgery will grow as new technologies emerge
Eyeworld,Jan,2003
We have only just begun to tap the refractive market in the United States, leaving substantial future opportunities in this area. Currently, only about 4% of Americans who are dependent on vision correction have had refractive surgery. This means that refractive surgery market penetration has actually been very small.Presently, there are about 1,200 refractive surgery centers in this country, and the good news is most of these are owned and operated by practitioners.Consider that about 25% of the population is myopic and the majority of these individuals are low myopes. Overall, the gorilla of the myopic procedures is still LASIK, although there has been a lot of talk and interest in LASEK. The technology I believe will be most important to the future of myopic surgery is wavefront-driven customized ablation.Other technology targeted at myopic patients includes phakic IOLs. Five or six years ago, I would have given the Ophtec Artisan Phakic IOL a 5% to 10% chance of success. However, our experience has actually been very positive. The STAAR ICL (implantable contact lens) is getting excellent results, and other companies are coming along with good technology, also.
Hyperopia patients tend to be older and have more disposable income than their myopic counterparts. However, fewer of these older patients are likely to want to undertake the risk of refractive surgery. I believe that a reasonable estimate is about 15 million hyperopia patients, which is about 30% of the overall refractive opportunity. I don’t believe this is an area that will ever predominate in refractive surgery.Surgeons today choose conductive keratoplasty (CK), or laser thermal keratoplasty (LTK) to treat lower levels of hyperopia. We’re getting excellent results with CK, much better than LTK, and the safety profile is certainly attractive to these patients. For higher levels, there is a lot of interest in refractive lensectomy, particularly for the presbyopic hyperope. This is one of the most rapidly growing procedures in my own practice, but LASIK still dominates. The presbyopic population in the United States is about 110 million, and of these, about 34 million (68 million eyes) are good candidates for surgery. Currently, most presbyopic people wear glasses or contact lenses. Surgeons have treated a few people with multifocal IOLs and a few investigational procedures, but surgery has really not penetrated this area in a meaningful fashion.Also promising, I believe, are the accommodating IOLs. C&C Vision is the leader in the United States and Human Optics is the accommodative lens used in Europe. One of the most exciting investigational technologies I have seen is the Calhoun Vision Light Adjustable Lens (LAL). This lens is made of a special polymer that allows the surgeon to adjust the power after implantation, and may even allow for accommodation or induced multifocality or wavefront adjustments. This will be an extraordinary advance and will move us toward intraocular lens surgery as a primary modality.Overall, the recent downtrend in refractive surgery volume I think will begin to reverse itself in the next year. The ophthalmology industry collaboration — clinicians working with business people — is driving improved technology and creating enhanced outcomes. I think that this will put us back on the pathway to growth.
Posted by MR.Taheri MD
Posted by at 10:16 PM
Femtosecond laser microkeratome offers advantages of ‘precisely centred’ thin flaps
Eurotimes jan,2003
Jonathan D. Christenbury MD presented results at the annual meeting of the American Academy of Ophthalmology from a series of 300 myopic eyes of 156 patients followed for one month after undergoing IntraLASIK with the femtosecond laser microkeratome for the lamellar keratectomy and the EC5000 excimer laser (Nidek) for ablation. Parameters used for flap creation in all eyes included a hinge angle of 60o, a side cut angle of 50o, diameter 8.5 mm to 9.3 mm, and thickness of 110 microns to 130 microns. Postoperative treatment included a topical antibiotic for one week and topical steroid drops tapered from QID to QD dosing over four weeks and then discontinued. Currently, steroids are tapered over two to three weeks.Uncorrected acuity was 20/20 or better in about 70% of eyes at the one-month follow-up visit. Some 98% achieved 20/40 or better UCVA. About 70% of eyes were within 0.5 D of their target MRSE and 95% were ±1.0 D. Two eyes experienced a two line loss from baseline BSCVA and about 15% had a single line decrease. BSCVA was improved one line from baseline in 12% of eyes and unchanged in about 70%.The results achieved in the six eyes in which flap creation was interrupted due to suction loss were comparable to the overall group. At one month, UCVA was 20/20 in five of the eyes and 20/30 in the sixth. Vision in all patients could be corrected to 20/20 or better.There were no thin/button-hole flaps or incomplete cuts. During follow-up over the next month, no eyes developed diffuse lamellar keratitis, corneal melts or epithelial ingrowth.The most common complications in the series of 300 eyes were epithelial defect/ abrasion (3.3%), striae/flap wrinkles (2.3%) and debris in the interface (1%). Dry eye was the most common patient complaint but its incidence was only 15%, much less than with standard LASIK. While use of a horizontal hinge has been shown to be beneficial for decreasing dry eye symptoms after standard LASIK, hinge location in the IntraLASIK procedure did not seem to affect the development of this problem.
Posted by S. Aliakbari
Posted by saliakbari at 05:51 PM
Correlation of Corneal Sensation, but not of Basal or Reflex Tear Secretion, With the Stage of Diabetic Retinopathy.
Cornea 2003 Jan;22(1):15-8
Both corneal sensation and total or reflex tear secretion are reduced in individuals with diabetes. The decrease in corneal sensation, but not that in each tear secretion, was correlated with the stage of diabetic retinopathy. Given that loss of corneal sensation is a manifestation of diabetic polyneuropathy, these results are consistent with the notion that both diabetic retinopathy and polyneuropathy result from a basement membrane abnormality.
posted by M.Riazi
Posted by at 12:29 AM
The Potential Role of PKC beta in Diabetic Retinopathy and Macular Edema.
Surv Ophthalmol 2002 Dec;47 Suppl 2:S263-9
Although numerous biochemical factors are thought to play a role in the development of retinopathy, activation of protein kinase C (PKC), specifically the beta isoform of PKC (PKC beta), is implicated for both the early and late-stage manifestations of retinopathy. Studies suggest that orally administered LY333531, a beta-isoform specific PKC inhibitor, may be effective in ameliorating retinopathy progression, proliferation, and retinal vascular leakage. The status of ongoing clinical trials aimed at addressing the efficacy of PKC beta with regard to diabetes-induced retinal complications and perspectives on the role of PKC beta are presented
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posted by M.Riazi
Posted by at 12:24 AM
ASCRS, AAPOS show similar trends in pediatric cataract surgery
Eyeworld,January,2003
Despite the continued threat of amblyopia, the visual prognosis for a child with a congenital, developmental or traumatic cataract has improved dramatically. However, pediatric cataract surgery remains complex and challenging. Achieving a consistently good visual outcome is difficult even for experienced and diligent surgeons. It is well recognized that the physical properties of young eyes differ markedly from those of the elderly. Yet, the case volume is insufficient for many to gain expert status.
The practice preferences of the American Society of Cataract and Refractive Surgery and the American Association for Pediatric Ophthalmology and Strabismus members with regard to pediatric cataract and IOL surgery were first surveyed in 19931. In cooperation with ASCRS and the Pediatric Clinical Committee, these memberships have recently (October 2001) been surveyed again in hopes of documenting current trends and changes in the practice of pediatric cataract surgery2.Almost one-third (30.5%) of the ASCRS surgeons reported doing pediatric cataract and IOL surgery (up from 27.3% eight years ago), while almost two-thirds (63.7%) of the AAPOS surgeons reported doing the surgery (up from 45.7% eight years ago). Overall, pediatric cataract preferences have evolved in the eight years since the previous survey. Acrylic IOLs are now the most common used and pseudophakia continues to be accepted for younger and younger-aged patients. However, the average case volume remains small with most performing fewer than 10 procedures a year.
Posted by A.Farahi MD,
Posted by afarahi at 12:12 AM
Retinal Damage from Indocyanine Green in Experimental Macular Surgery
Investigative Ophthalmology and Visual Science
Conclusion: The spectral absorption properties of ICG may account for a possible photodynamic effect of ICG at the vitreoretinal interface. ICG alone induces ILM detachment and disruption of Müller cells even without intentional peeling of the membrane. It is assumed that accumulation of the dye at the vitreomacular interface may enhance the concentration and osmolarity of ICG at the retina beyond intravitreous values and critical limits...
Reposted by M.Riazi
Posted by at 12:11 AM
Management of keratoconus with Intacs
American Journal of Ophthalmology Volume 135, Issue 1, January 2003, Pages 64-70
To prospectively study the effects of the use of Intacs microthin prescription inserts for the management of keratoconus.thirty-three eyes of 26 keratoconus patients with mean age of 32 ± 9.7 years were included in the current study. All patients had clear central corneas and contact lens intolerance.Two Intacs segments of 0.45-mm thickness were inserted in the cornea of each eye, aiming at embracing the keratoconus area to try to achieve maximal flattening.Intacs were successfully implanted in all eyes. In one eye Intacs were removed after 3 months because of their improper (superficial) placement. The follow-up ranged from 1 to 24 months (mean: 11.3 months). The mean UCVA significantly improved from 0.13 ± 0.14 (range, counting fingers [CF]–0.5) to 0.39 ± 0.27 (range, CF-1.0) (P < .01). Of 33 eyes, 2 eyes lost 1 line of UCVA, and 3 eyes maintained the preoperative UCVA, whereas the rest (28 eyes) experienced a 1- to 10-line gain. The mean BCVA also improved from 0.47 ± 0.31 (range, CF-1.0) to 0.64 ± 0.26 (range, 0.1-1.0) (P < .01). Of 33 eyes, 4 eyes experienced 1- to 2-line loss of BCVA, 4 eyes maintained the preoperative BCVA, whereas the rest (25 eyes), experienced a 1- to 6-line gain. Of 3 patients (3 eyes) with unsatisfactory results, 1 patient improved with one segment removal and in 2 patients the segments were permanently removed. One of these eyes underwent successful PKP.
posted by A.Gholaminejad MD
Posted by at 12:10 AM
January 11, 2003
63 year old woman with red eye ,what is your diagnosis?
Presenting History:A 63 year old woman presented to an outside ophthalmologist with foreign body sensation, irritation, photophobia, and tearing OD. Slit lamp exam notable only for superficial punctate keratitis OD She was treated with erythromycin ointment with some improvement.She re-presented to her outside ophthalmologist with worsening OD photophobia, redness, tearing, blurry vision, and pain. Corneal sensation was noted to be absent OD but intact OS. The exam was notable for eyelids without vesicles, conjunctival injection, corneal epithelial irregularity with small defect, mild corneal edema, keratic precipitates, and mild anterior chamber reaction.A pressumptive diagnosis of herpes simplex virus (HSV) keratouveitis was made, and she was started on oral acyclovir (800mg 5x/day). Initially her symptoms improved slightly, but 1 week later she developed worsening corneal edema and anterior chamber reaction. Pred Forte was added TID resulting in reduced corneal edema and anterior chamber reaction. However, two weeks later, she developed worsening photophobia and pain.
Previous ocular history: Myopia (rigid gas permeable contact lenses x 40 years)
Past Medical History:Chicken pox as a child
Medications: none
Family and Social History:non-contributory
Examination demonstrates corneal- ring infiltrate, central epithelial defect, stromal edema,Descemet's folds, and keratic precipitates
Posted by M.Khanlari MD,
Posted by at 11:37 PM
Higher birth weight associated with increased AMD risk, study finds
OSN,12/9/02
SOUTHAMPTON, England — Higher weight at birth was associated with an increased risk of developing age-related macular degeneration in a retrospective study here.
The researchers sought to determine whether poor fetal growth was associated with an increased risk of AMD. Poor fetal growth was determined by the patients’ sizes at birth. The researchers found, surprisingly, that patients with AMD had greater mean birth weights than those without (7.6 lb. compared to 7.3 lb., P = .03). After adjusting for age, gender and risk factors for developing AMD, the researchers found a significantly increased risk of AMD in patients with greater weight at birth. One measure of fetal proportion — the ratio of head circumference to birth weight — was also significantly associated with increased risk of AMD. Patients with AMD had a significantly lower head circumference-to-birth weight ratio than those without (11.2 compared to 12, P = .01). The finding that age-related macular degeneration was associated with increased rather than decreased birth weight was unexpected. Failure of the developing fetus’s normal brain-sparing mechanism is a possible explanation for our finding of a lower head circumference-to-birth weight ratio among subjects with macular degeneration,” the authors reported.
Posted by M.Khanlari MD,
Posted by at 11:03 PM
Study on Road Safety May Drive Cataract Candidates to Surgery
The Journal of the American Medical Association2002; 288:841–841, 885–886
Older patients who undergo cataract surgery and IOL implantation experience about half the rate of motor vehicle crashes four to six years later than cataract patients who do not undergo surgery, report Owsley et al.The results indicated that the crash rate for those undergoing cataract surgery increased only 27 percent in the follow-up period, which was four to six years, compared with 75 percent for those who did not choose surgery.The authors conclude that cataract surgery has an undocumented benefit for everyday life—specifically preventing the increased crash rate that would be anticipated without cataract removal—and that ophthalmologists could use this data when discussing the benefits and risks of cataract surgery with their patients.
Posted by A R Naderi MD,
Posted by at 10:46 PM
Statin plus antibiotic may increase cataract risk
OSN ,12/3/02
KIRKSVILLE, Mo. — Use of an antibiotic in combination with a common cholesterol-lowering drug may significantly increase the risk of cataract development, according to both laboratory and population-based research. A recently published study in rats may support a previous study that found taking cholesterol-lowering drugs in combination with agents that slow the metabolism of statins in the body, such as erythromycin, could increase the risk of cataract development.According to the report, this particular strain of rats has a genetic defect affecting the control of hydroxymethyl glutaryl coenzyme A (HMG CoA) synthesis. While sterol synthesis markedly increased in the other rat strains, sterol synthesis remained at baseline levels in these rats. This may be due to inadequate upregulation HMG CoA synthesis in the lens, the authors speculated. Upregulation of the sterol pathway may result in increased isoprene-derived anti-inflammatory substance formation, they posited. Erythromycin is known to significantly increase the systemic bioavailability of statins. In the study, people taking both simvastatin and erythromycin had as much as three times the risk of cataract development as those not taking both drugs.
Posted by M.Khanlari MD,
Posted by at 10:27 PM
Intraoperative Arcuate Transverse Keratotomy With Phacoemulsification
[J Refract Surg 2002;18: 725-730]
Conclusion.A combination of intraoperative arcuate keratotomy with steep axis phacoemulsification incision is more effective than steep axis phacoemulsification incision alone in reducing pre-existing astigmatism.
Posted by M. Khanlari MD,
Posted by at 08:55 PM
Retinal Damage from Indocyanine Green in Experimental Macular Surgery
Investigative Ophthalmology and Visual Science. 2003;44:316-323.)
Previous work has shown that indocyanine green (ICG)–assisted peeling of the inner limiting membrane (ILM) may cause retinal damage. The spectral absorption properties of ICG may account for a possible photodynamic effect of ICG at the vitreoretinal interface. ICG alone induces ILM detachment and disruption of Müller cells even without intentional peeling of the membrane. It is assumed that accumulation of the dye at the vitreomacular interface may enhance the concentration and osmolarity of ICG at the retina beyond intravitreous values and critical limits
Posted by M Khanlari MD,
Posted by at 08:47 PM
Randomized, clinical trial of multiquadrant hydrodissection in pediatric cataract surgery
AJO,January,2003
Maintenance of a clear visual axis is a high priority when planning the management of cataracts in pediatric patients. Various invasive modalities have been proposed to ensure a clear visual axis. However, we apply hydrodissection, an inexpensive, practical, immediately implementable, noninvasive procedure to pediatric cataract surgery During the hydrodissection procedure, as the fluid is injected directly under the anterior capsule, it causes a visible fluid wave. The presence of this fluid wave is regarded as a sign of successful hydrodissection in adult eyes. But the pediatric eye behaves a bit differently. The fluid wave may not always be visible to the surgeon in pediatric eyes. In our experience, the adhesion between the cortex and the capsule is very strong in pediatric patients. This strength prevents the fluid wave from traversing between the posterior capsule and the posterior cortex. Other signs of a successful hydrodissection include a forward bulge of the nucleus, rhexis block, prominence of the capsulorhexis edge, and release of trapped fluid from the rhexis margin following decompression of the nucleus. However, in pediatric eyes it is always better to carefully apply multiple quadrant hydrodissection. Multiple quadrant hydrodissection is the key to the removal and wash out of equatorial LECs, and we strongly recommend it in pediatric eyesMultiquadrant cortical-cleaving hydrodissection decreases lens substance removal time, lessens fluid volume used for lens substance removal, and facil-itates lens substance removal in pediatric cataract surgery.
Posted by M Tabrizi M.D
Posted by at 12:43 AM
Characteristics of Visual field Defects in Primary Glaucoma: POAG vs. PACG
Archives of Ophthalmology 2002;120:1,636–1,643
Gazzard et al. report the characteristics of visual field defects in patients with primary open-angle glaucoma (129 patients) and those with primary angle-closure glaucoma (105 patients). Automated static perimetry was performed. Patients with POAG were noted to have more severely affected superior hemifields, while this finding was less pronounced in patients with PACG. The authors believe that this finding may give insight into the pattern of visual loss in predominantly pressure-dependent glaucomatous optic atrophy
Posted by M.Khanlari MD,
Posted by at 12:00 AM
January 10, 2003
Glaucoma and Visual Fields
Ophthalmology February(preview),2003
To evaluate the regions of the central visual field most important for quality of vision, Sumi et al. conducted a prospective, noncomparative survey of 147 Japanese patients with glaucoma. Using a previously developed questionnaire, they assessed the relationship between visual disability indices and both the visual field examined with program 30-2 of the Humphrey Field Analyzer and visual acuity.Results indicated a strong correlation between visual disability and the visual measurements collected. Specifically, loss of retinal sensitivity in the lower hemifield within five degrees of fixation, loss of central visual acuity in the better eye and secondarily loss of visual acuity in the worse eye were significant factors in the patients’ visual disability.Because glaucomatous damage tends to be more severe in the lower central field of myopes, the authors call for more aggressive early treatment of Japanese POAG patients with myopia.
Posted by M.Khanlari MD
Posted by at 11:55 PM
What do you see?
Eyenet,,Jan,2003
Posted by M.Khanlari MD,
Posted by at 11:14 PM
Monitoring Drug Side Effects
Eyenet,Jan,2003
Knowledge of systemically administered medications and their potential ocular side effects is an important foundation of the practice of ophthalmology. Macular retinal pigment epithelial degeneration can occur with hydroxychloroquine use and is only reversible early in the course of the toxicity.Early recognition is the best defense against serious visual loss; once later findings (retinal changes, color vision loss, absolute scotoma or decreased vision) occur, these changes are irreversible, even when the drug is stopped..Corneal deposits commonly develop, especially at higher doses (400 mg/day) with Amiodarone. .The deposition ranges from a mild linear pattern to a larger whorl pattern. As with chlorpromazine deposits, these deposits are most visible with retroillumination through a dilated pupil. Usually the deposits do not interfere with vision and disappear months to years after the drug is discontinued.Niacin can cause a maculopathy that resembles cystoid macular edema. . This finding is usually bilateral and affects men more commonly than women. Changes in visual acuity have been reported even in the absence of macular edema Chlorpromazine is associated with ocular pigmentary deposits on the lens surface, Descemet’s membrane and, less commonly, the corneal endothelium and conjunctiva. While retinal pigmentary changes can occur with chlorpromazine, they are more common with another member of the phenothiazine family, thioridazine. In this case, there is pigment loss in a nummular pattern, which can extend from the macula to the mid-periphery. The pigmentary changes seen with chlorpromazine seem to be reversible.
Posted by A R Naderi MD,
Posted by at 06:26 PM
Trabeculectomy or Viscocanalostomy for the Control of Intraocular Pressure in Open-Angle Glaucoma?
British Journal of Ophthalmology 2002; 86:748–754
Viscocanalostomy is a nonpenetrating technique designed to manage uncontrolled glaucoma. In this approach, deroofing of Schlemm’s canal and creation of a Descemet’s window are followed by injecting viscoelastic into the canal in an attempt to bypass the trabecular meshwork while maintaining and opening the normal anatomical drainage channels.O’Brart et al. compared this method with trabeculectomy for the control of IOP in open-angle glaucoma. They randomized 48 patients (50 eyes) with uncontrolled OAG to either trabeculectomy or viscocanalostomy.The researchers found that trabeculotomy—augmented with the use of intraoperative antimetabolites in cases at risk of drainage failure—was better than viscocanalostomy at controlling IOP in OAG. While viscocanalostomy is less invasive and may possibly reduce reliance on subconjunctival drainage, and is generally associated with fewer postoperative complications, especially cataract formation, the researchers conclude that trabeculectomy continues to be the filtering procedure of choice to control IOP.
posted by A R Naderi MD,
Posted by at 05:33 PM
Lens Aging in Relation to Nutrition and Risk Factors for Cataract
Archives of Ophthalmology 2002;1120:1,732–1,737
Berendschot et al. investigated whether nutritional factors and possible risk factors for cataract might influence the optical density of the lens in a total of 376 subjects.
They noted no apparent association between the optical density of the lens and other possible risk factors for age-related cataract, nor with serum or adipose tissue concentrations of carotenoids, vitamin C and alpha-tocopherol (vitamin E). They therefore conclude that an inverse relationship between optical density of the lens and macular pigment optical density suggests that lutein and zeaxanthin may retard aging of the lens.
Posted by A R Naderi MD,
Posted by at 05:03 PM
Refractive Lens Exchange With an Array Multifocal Intraocular Lens
JRS September 2002
Fifty eyes of 25 patients (mean age 51 years, range 44 to 62 years) with preoperative spherical equivalent refraction between -15.50 and +5.75 D and cylinder between 0 and 1.50 D underwent bilateral implantation of a zonal progressive multifocal IOL (Array, AMO). Eyes were divided into group A (n=24; myopia, average preoperative spherical equivalent refraction -7.11 ± 3.25 D (-1.75 to -15.50 D), and group B (n=26; hyperopia, average preoperative spherical equivalent refraction +3.04 ± 1.04 D). Follow-up was 6 months in all eyes. Postoperatively, all eyes of both groups were within ±1.00 D of target refraction. No eye in group A and three eyes in group B sustained a loss of one line of BSCVA. Forty-seven eyes (94%) remained unchanged or gained one or more lines of their preoperative BSCVA. In all eyes, postoperative UCVA was 20/40 or better. When compared to preoperative, uncorrected near visual acuity improved (statistically significant). All patients achieved uncorrected binocular visual acuity of 20/30 and J4 or better. Patient satisfaction was extremely high; no intra- or postoperative complications were reported. CONCLUSION:
Six-month results of implantation of the AMO Array multifocal IOL for refractive lens exchange demonstrated safety, efficacy, and predictability in correcting high ametropia and significant improvement of uncorrected near and distance visual acuity.
Posted by Alireza Habibollahi,MD
Posted by at 03:56 PM
Cell Phones, Driving Can Lead to Tunnel Vision
Eyenet Jan 2003
It isn’t holding the phone to your ear that creates problems when you talk on the cell phone in the car. It’s that you develop “tunnel vision” from concentrating on the conversation, according to a study by University of Rhode Island researchers.Manbir Sodhi, PhD, a professor of industrial engineering, led the research team, which included an expert in visual perception. They used a head-mounted device to track eye movements. Study subjects were measured in their own cars while they were driving and trying to do cognitive tasks, and while driving and talking on a cell phone at the same time.During normal driving, they found, drivers’ eyes scanned the road environment widely and frequently. The longest they took their eyes off the road (for example, to adjust the radio) was 1.6 seconds. But when trying to remember a list or do mental math, or when talking even on a hands-free cell phone, eye movements decreased and their range narrowed—creating tunnel vision.Interestingly, conducting a conversation with a car passenger doesn’t create the same effect, Dr. Sodhi said. “Talking to someone is a distraction, but it’s not necessarily under your control. That’s what seems to make the difference between normal conversation and talking on a cell phone,” he said.So hang up and drive
Posted by A R Naderi MD,
Posted by at 11:55 AM
Smoking may cause blindness in 20% of over 50-year-olds
Eurotimes,january,2003
Findings from population-based eye disease studies conducted on three continents provide strong evidence that smoking is the principal known risk factor associated with age-related macular degeneration (AMD), according to an Australian ophthalmologist.Age, gender, smoking, body mass index, iris colour, hormonal factors and cardiovascular among other diseases, were assessed as potential risk factors using logistic regression analysis techniques. The results showed a strong increase in AMD prevalence with increasing age, but smoking was the only other significant risk factor clearly associated with both types of AMD. The data included approximately 12,500 people aged 55 to 86 years. AMD prevalence rates were less than 0.5% for persons under 65 years, 1% for those aged 65 to 74 and 5% for those aged between 75 and 84.The rate rose sharply to almost 15% for those aged 85 years and older. Compared with a reference group of people under age 70, those in their 70s had a six-fold increased risk of AMD, while those in their 80s were 25 times more likely to have AMD. Compared with lifelong non-smokers, past smokers had a 30% increased risk of AMD while the risk was increased 300-fold among current smokers.A recent Australian national campaign to encourage smokers to quite focused on the habit as a risk factor for blindness. In addition, Dr Mitchell has called for a new cigarette pack warning: Smoking causes blindness.
Posted by A.Naderi MD,
Posted by at 11:30 AM
Orbscan II alternative to infrared pupillometry if...
Eurotimes january 2003
Refractive surgeons recognise that determining mesopic pupil size is an important measurement in planning LASIK procedures because a mesopic pupil smaller than the ablation area may contribute to the development of glare, halos and other night vision disturbances after LASIK.The Orbscan II® (Bausch & Lomb) provides a valid alternative to infrared pupillometry for calculating mesopic pupil size in patients undergoing excimer laser refractive surgery.Speaking at the annual meeting of the American Academy of Ophthalmology, Lewis R. Groden MD and colleagues The Keeler pupillometer measurements were obtained in very dim light conditions and were recorded to the nearest 0.1 mm. The Orbscan II examination was conducted under normal light and since light is projected during data acquisition, an arbitrary value of 2.5 mm was added to the pupil size reported to account for pupillary constriction occurring under the higher luminance conditions.Statistical analyses performed using both a two sample T-test and the Wilcoxon rank-sum test showed there was no significant difference in the mean pupil size values determined by adding 2.5 mm to the pupil size obtained with the Orbscan II and the meospic pupil size measurements acquired using the infrared pupillometer.
Posted by M.Miraftab MD,
Posted by at 01:12 AM
New hypotheses emerge on causes of wet AMD
Eurotimes january 2003
“The choroid is an active tissue where there’s intrachoroidal cellular recruitment and new vessel formation. So abnormal new blood vessels arise from deeper within the choroidal tissue, giving rise to both intrachoroidal and subretinal new vessels. This suggests that now the choroid is playing a crucial role in the formation of this disease,”
Animal experiments indicate that the abnormal new vessels may arise from circulating bone marrow-derived precursor cells. Transplantation of genetically ‘marked’ bone marrow into animals shows that marrow-derived cells are recruited to the site of experimentally induced choroidal neovascularisation
Posted by M.Miraftab MD
Posted by at 01:07 AM
WHO initiative targets childhood blindness
Eurotimes january 2003
GOTHENBURG — Because childhood blindness is either treatable or easily preventable in at least half of all cases, the World Health Organisation (WHO) has identified the condition as a priority area in its Vision 2020 initiative."Childhood blindness has been selected as a priority area because it contributes hugely to overall blind years and is associated with high mortality. It also requires special training and expertise to manage properly.Defining blindness as visual acuity of 20/200 or worse and childhood as less than 16 years of age, the current WHO estimates of the prevalence of childhood blindness range from 0.3/1000 children in high-income countries to 1.2/1000 children or more in poorer countries.about 73% of blind children are living in the poor and very poor countries of Asia and sub-Saharan Africa.
Posted by M.Miraftab MD,
Posted by at 12:59 AM
January 09, 2003
Pirenzepine, a drug for the treatment of myopia
OSN JANUARY 2003
BASEL, Switzerland — Novartis Ophthalmics has acquired the rights to market . Novartis will own worldwide marketing rights to the drug, currently in phase 2 trials by developer Valley Forge Pharmaceuticals. Pirenzepine is described in a press release from Novartis as “a relatively selective muscarinic M1 receptor antagonist administered as an eye gel twice a day.” The drug is expected to reduce the progression of myopia by up to 50%, according to the press release.
A multicenter phase 2 trial of the drug has enrolled 174 children aged 8 to 12, with myopia in both eyes. The mean baseline cycloplegic refractive error was –2.04 D in the right eye and –2.05 D in the left eye. Children were randomized to receive 2% pirenzepine ophthalmic gel or vehicle for 1 year. Key measures of efficacy will include cycloplegic autorefraction, axial length by ultrasonography, visual acuity, biomicroscopy, indirect ophthalmoscopy, pupil diameter and intraocular pressure.
phase 2 trials have shown the drug to reduce the progression of myopia by at least 50% in the first 12 months of therapy.
“This novel compound … could set new standards for the treatment of this eye disorder, since there is no pharmacological therapy available today,
Posted by M.Miraftab MD,
Posted by mmiraftab at 09:49 PM
A simplified diabetic retinopathy grading scheme
"International Clinical Classification for Diabetic Retinopathy."
Medscape.com
This system utilizes the "4-2-1 rule," commonly employed by diabetic retinopathy experts for establishing the presence of severe NPDR.
Specifically, the classification recognizes the following retinopathy levels:
No apparent diabetic retinopathy
Mild NPDR:microaneurysms only
Moderate NPDR:More than just microaneurysms but less than severe NPDR
Severe NPDR
PDR:Neovascularization and/or vitreous/preretinal hemorrhage
In addition, the presence or absence of macular edema is reported. The cutoff of severe NPDR is derived from the "4-2-1 rule" where presence of the following would qualify for this level if no PDR is present:
4 quadrants of hemorrhages or microaneurysms greater than ETDRS standard photograph 2A (> 20 retinal hemorrhages); or
2 quadrants of venous beading; or
1 quadrant of IRMA equal or greater than ETDRS standard photograph 8A (prominent)
Posted by M.Miraftab MD,
Posted by mmiraftab at 09:24 PM
New Findings:Retinal angiomatous proliferation (RAP) is described as a type of AMD
This study described the occurrence of this condition in a group of 115 patients from a retinal referral practice of newly diagnosed patients with exudative AMD. Patients were evaluated by fundus photography, indocyanine green (ICG) angiography, and fluorescein angiography (FA). Patients with RAP accounted for 20.8% of the group, while classic and occult (with or without a classic component) represented the remainder. Different stages of RAP were described. The authors raised the possibility that patients at different stages may react differently to treatment. Their identification, facilitated by the combination of FA and ICG, may help in tracking their response to different treatment modalities. In discussing this paper, Dr. Barbara Blodi remarked that clinical examination and FA alone are often able to identify this entity. She also felt that the incidence was probably higher in a specialty referral practice than would be expected if any and all exudative AMD patients were included.
Posted by M.Miraftab MD,
Posted by mmiraftab at 09:12 PM
The Latest Findings in Glaucoma: the OHTS, AGIS, and CIGTS
Posted by M.Miraftab MD,
Posted by mmiraftab at 09:04 PM
Polymer Refilling of Presbyopic Human Lenses In Vitro Restores the Ability to Undergo Accommodative Changes
Investigative Ophthalmology and Visual Science. 2003;44:250-257.)
Because presbyopia is thought to be accompanied by increased lens sclerosis this study was conducted to investigate whether refilling the capsule of the presbyopic human lens with a soft polymer would restore the ability of the lens to undergo accommodative changes. Accommodative forces were applied to natural and refilled lenses by circumferential stretching through the ciliary body and zonular complex. Nine natural lenses and 10 refilled lenses from donors ranging in age from 17 to 60 years were studied. Two refill polymers with a different Young’s modulus were used. The lens power was measured by a scanning laser ray-tracing technique, and lens diameter and lens thickness were measured simultaneously while the tension on the zonules was increased stepwise by outward pull on the ciliary body. In the natural lenses the older lenses were not able to undergo power changes with stretching of the ciliary body, whereas in the refilled lenses, all lenses showed power changes comparable to young, natural lenses. The refilled human lenses had a higher lens power than the age-matched natural lenses. Refilling presbyopic lenses with a soft polymer enabled restoration of lens power changes with mechanical stretching. Because sclerosis of the lens is an important factor in human presbyopia, refilling the lens during lens surgery for cataract could enable restoration of clear vision and accommodation in human presbyopia.
Posted by M.Khanlari MD
Posted by at 07:47 PM
Could CAT-152 be an alternative to MMC or 5FU for preventing wound scarring after trabeculectomy?
OSN/Jan/2003
Early clinical trial data on CAT-152 indicate the drug could prevent postoperative wound scarring following trabeculectomy. The monoclonal antibody may be a less damaging alternative to 5-fluorouracil or mitomycin-C, said David C. Broadway, MD, FRCOphth.
“ we do get the impression we are producing blebs that are more physiological,” he said. “They are not thin, horrible, cystic blebs that can develop following the use of other antiproliferative agents. They appear to be more diffuse and have normal conjunctival thickness.
“CAT-152 doesn’t act on the cell. It’s actually mopping up the TGFß2, which is stimulating the cells. It is not killing cells
Early clinical data on CAT-152 suggest that the drug could be an alternative to mitomycin-C and 5-fluorouracil for preventing postoperative wound scarring following trabeculectomy.
posted by M. Pakravan
Posted by at 12:24 AM
Papillorenal Syndrome in a Brazilian Family
archives of ophthalmology/Dec/2002
Cameron F. Parsa, MD
. Characteristic findings in papillorenal syndrome, consist of an absence or attenuation of the central retinal vessels within the optic nerves, with multiple compensatory cilioretinal vessels present.The recent plethora of affected families suggests that papillorenal syndrome has been clinically underrecognized. Over the course of a year, one of us (Cameron F. Parsa) identified 12 affected families during ophthalmic examinations unrelated to renal status. The ophthalmologist should consider screening for renal disease in patients with multiple cilioretinal vessels suspected of having papillorenal syndrome. Tests for microalbuminuria will often reveal renal dysfunction in these patients prior to the development of electrolyte imbalances. Ultrasonography may reveal hypoplastic, cystic, or echogenic kidneys prior to the development of any functional deficits.
posted by M. Pakravan
Posted by at 12:00 AM
January 08, 2003
Family Score as an Indicator of Genetic Risk of Primary Open-Angle Glaucoma
Arch Ophthalmol. 2002;120:1726-1731
To assess the genetic risk of open-angle glaucoma (OAG) in individuals by calculating a family score (FS), which summarizes the information of all relatives including their disease status, age, sex, and degree of kinship and to examine the genetic contribution to OAG with and without an increased intraocular pressure.
Case and control probands, derived from the Rotterdam Study, underwent the same ophthalmologic examination as their relatives. The FS of each proband was the sum of the differences between observed and expected values of OAG for all relatives. The FSs were compared between case and control probands using logistic regression analysis, adjusted for intraocular pressure.
Conclusions These data show that the FS strongly predicts OAG, independent of the intraocular pressure. Therefore, the FS is useful to identify individuals with a high genetic risk.
Posted by M.Miraftab MD
Posted by mmiraftab at 11:44 AM
Adjustable IOL in Testing
Eyenet,July,2002
Incorrect refractive power is the No. 1 reason that IOLs need to be removed. So a lens that would let ophthalmologists correct the problem without surgery or eyeglasses would cause a stir.And that’s just what’s happening with the Light Adjustable Lens from Calhoun Vision in Pasadena, Calif., whose refractive power can be adjusted with external laser light. The IOL is expected to undergo its first human testing this summer in Tijuana, Mexico, at the clinic of Arturo S. Chayet, MD.The idea and impetus for the Calhoun lens came from an ophthalmologist—the company’s chair, Daniel M. Schwartz, MD, who also is director of the retina service at the University of California, San Francisco. But the materials science know-how came from experts he found at the California Institute of Technology.They devised a silicone polymer combined with macromers, molecules that have reactive end-groups. These bond together into polymers when hit with UV light, Mr. Sharma said. When this happens, the remaining macromers migrate toward the irradiated area, changing the IOL’s shape and refracting power.To steepen the lens, pulses would be aimed at the center, causing macromers to migrate there and making the center bulge slightly. To flatten the IOL, a ring of pulses around the periphery would do the trick. These adjustments would be done at the slit lamp after the cataract patient’s eye had healed from the surgery. Later, if the patient is happy with the fine-tuning, a wash of UV light would be applied to the IOL, sealing the final focusing power into place.
Posted by Sh.Ebadollahi
Posted by at 12:41 AM
Amniotic membrane transplantation for reconstruction of the conjunctival fornices
Ophthalmology,January,2003
Amniotic membrane transplantation was done by authors for seventeen eyes in 15 patients with symblepharon. Four eyes had ocular-cicatricial pemphigoid, two eyes had symblepharon after pterygium excision, four eyes had chemical or mechanical trauma, two eyes had strabismus surgery, two eyes (one patient) had Stevens-Johnson syndrome, one eye had toxic epidermal necrolysis, and two eyes (one patient) had chronic allergic conjunctivitis.
. The most successful outcome was observed in eyes with symblepharon associated with trauma.
They concluded that: AMT is an effective method of fornix reconstruction for the repair of symblepharon in a variety of ocular surface disorders. Future modifications, including an epithelial cellular component on the AM (conjunctival autograft or ex vivo expanded epithelial stem cells) may improve the outcome of this surgical procedure.
Posted by A.Farahi MD
Posted by at 12:10 AM
January 07, 2003
Cryoanalgesia affords drug-free anaesthesia for phaco
Eurotimes,January,2003
ORLANDO, FL - Cryoanalgesia is a safe and viable method for mitigating pain and discomfort in patients undergoing phacoemulsification.Cryoanalgesia involves operating in a cooled environment created by preoperative cooling of the eye and use of chilled fluids. Proponents say cryoanalgesia minimises pain and inflammation by diminishing the release of endogenous chemicals mediating those reactions and by decreasing corneal metabolism. In the cryoanalgesia cold (4şC) BSS was used to irrigate the ocular surface throughout surgery. Patients received no sedatives preoperatively or any non-steroidal anti-inflammatory drops.Patients operated on under cryoanalgesia reported significantly more pain than their counterparts in the topical anaesthesia group.In addition, it may minimise endothelial trauma from the heat of the phacoemulsification tip and the low temperature environment might inhibit growth of bacteria which could contribute to endophthalmitis. He said he hopes to study these benefits further in the future.
Posted by M.Khanlari MD,
Posted by at 11:23 PM
New 3-D monitor brings surgery into digital world
Eurotimes,January,2003
NUERNBERG — Why stare into a microscope eyepiece when you can perform surgery viewed on a large freestanding 3-D screen? An updated viewing system should accompany the advancement of optical surgical devices and machinery. Ophthalmology is developing in line with other surgical fields which have discovered that a 3-D monitor affords the surgeon an ergonomical and modern workplace. The system, developed by German company SeeReal GmbH, uses a stereoscopic viewing system to produce 3-D intraocular images. A computer program digitally slices the images into parallel segments and renders a stereoscopic composite image. Surgeons see “augmented reality” images of the ocular surface, anterior chamber and vitreous space. The eye anatomy seems somewhat larger and has a plastic effect.
Posted by M.Khanlari MD,
Posted by at 11:09 PM
EU guidelines give optimal correction licence to fly
Eurotimes,January,2003
BERLIN — The new EU Joint Aviation Requirements-Flight-Crew Licensing (JAR-FCL 3) guidelines, scheduled to take effect this month, significantly broaden the range of permissible visual correction for candidate pilots.
While professional pilot licensing strictly enforced a maximum correction of 3.0 D irrespective of corrected visual acuity, the licensing EU committee has expanded the inclusion criteria for future pilot candidates and stipulate that as long as no significant deviations from the norm or pathological changes exist, and vision is optimally corrected, both private and professional pilots can be licensed with visual acuity up to 5.0 D measured in the first-time examination. Highly myopic candidates up to -8.0 D may obtain and keep a licence if monitored every two years by an ophthalmologist. A specialised ophthalmological examination is required only for the first-time eye examination, as well as in cases that deviate from the norm or appear unclear to the examiner. This examining ‘flight doctor’ must be a medical specialist with additional training in air and space medicine. The experts set the astigmatism limit for professional pilots at 1.5 D. There is no limit for private pilots. At the first examination, professional pilots may not exceed 2.0 D, or 3.0 D at the follow up visits. Private pilots must wear contact lenses or glasses to correct astigmatisms in excess of 3.0 D.Candidates with anisometropia may not present with values above 3.0 D. However the limit for professional pilots at the first exam is set at 2.0 D and may not exceed 3.0 D in monitoring exams.The Ishihara pseudochromatic colour tables, Nagel Anomaloscope and signal light tests are options the ophthalmologist may consider to determine a candidate’s colour perception. Private pilot candidates who have poor colour perception have the option to become licensed for daytime flying using visual flight rules (VFR) only within the flight-information-area in JAR-member-states.Patients undergoing cataract surgery must wait three months after surgery until they can apply for a licence to fly. Visual field defects are additional exclusion criteria. An expert witness must be called in cases of doubt. A six-month time frame was set for (re)-licensing in retinal-operated and glaucoma-operated candidates.
Posted by M.Khanlari MD,
Posted by at 11:02 PM
January 06, 2003
Cutting to the truth about corneal ectasia
Eyeworld ,January,2003
One of the most serious LASIK complications a patient can encounter is corneal ectasia, a condition that can lead to progressive myopia and astigmatism, loss of uncorrected acuity, and loss of best-corrected acuity. Unfortunately for the physician, it can be difficult to predict which patients are likely to develop ectasia. However, investigators now find that several risk factors, including high myopia, forme fruste keratoconus, optical zone size, and high intraocular pressure, likely play an important role. Indeed, one study indicates that 88% of patients who developed ectasia had forme fruste keratoconus.
Investigators found that there was an important collective interplay between the optical zone size, ablation depth and intraocular pressure. The thin residual bed, the small optical zone (5 mm optical zone) and the high intraocular pressure produced more corneal ectasia, and the thick residual bed, the large optical zone (8 mm/9 mm) and the low intraocular pressure produced less corneal ectasia,We ask you to consider the use of the ocular hypotensive drugs in cases of corneal ectasia after LASIK,” Cosentino said.
Posted by M.Khanlari MD,
Posted by at 11:47 PM
Taking the pain out of PRK
Eyeworld, January,2003
Photorefractive keratectomy continues to evolve. Unique approaches are speeding visual recovery and helping make PRK more comparable, in terms of pain, to LASIK.
In recent years, postoperative pain and subepithelial corneal haze formation has been attributed to corneal temperature increase during PRK,” Dausch said. “Our measurement with a noncontact infrared camera showed that during the ablation, you have peaks of temperature up to 42° C.” Such temperature approaches the point of protein degeneration.This calls for a change in method, Dausch said. “To prevent thermal damage and help with cooling, a stream of room-temperature smoke, generated by an atomizer, is spread across the cornea at a forced rate of 3 meters/second. With this modified PRK technique, corneal temperature in a pig’s eye rose to just 13.7° C during a demonstration, compared with a maximum of 21.4° C with conventional PRK.When patients were asked on the first postoperative day to rate, on a scale of 0 to 10, the worst level of pain they had experienced, on average, modified PRK was rated 2.24. Meanwhile, after conventional PRK, values ranged between 3 and 6.82. Study results indicated that 90% of patients treated with the modified approach complained only of foreign-body sensation, with no serious pain. Oral medication for pain was necessary in only 10% of cases, Dausch found. With this approach, the epithelium healed more rapidly — after 2.5 days on average. Visual acuity also returned more quickly
Posted by M.Khanlari MD
Posted by at 11:34 PM
Repeatability and validity of Zywave aberrometer measurements
JCRS December 2002
With a dilated pupil, the Zywave measurements were significantly more myopic than subjective refractions and even more myopic than cycloplegic autorefractions. Zywave measurements and subjective refractions were in better agreement with a 3.5 mm pupil. The repeatability of Zywave aberrometer measurements is adequate for lower-order aberrations.
Posted by M.Miraftab MD,
Posted by at 11:11 PM
Posterior chamber intraocular lens supported by an intact vitreous face
JCRS December 2002
Describe a technique of posterior chamber intraocular lens (IOL) implantation in eyes with inadequate capsule support caused by inadvertent or planned intracapsular cataract extraction (ICCE) or in eyes having secondary IOL implantation after previous ICCE. The procedure is only performed in eyes with an intact anterior vitreous face, no vitreous prolapse into the anterior chamber, and no vitreous loss. The anterior vitreous is pushed back by viscoelastic material or air. The viscoelastic material is injected under the iris to create a free space between the iris and anterior vitreous. A single-piece, C-loop, poly(methyl methacrylate) IOL is slid onto the iris to rest on the anterior vitreous face; care is taken not to disturb the anterior vitreous. The technique was used in 15 eyes with a follow-up from 19 months to 5 years. All eyes had a stable IOL at each follow-up, and the visual acuity was 6/12 or better at the last follow-up.
Posted by M.Miraftab MD,
Posted by at 11:06 PM
DURATION OF AND INCIDENCE OF SKIN PHOTOSENSITIVITY REACTIONS WITH VERTEPORFIN
RETINA 2002; 22(6):691-697
Verteporfin (Visudyne, Novartis AG) is a light-activated drug that reduces the risk of vision loss in patients with certain types of choroidal neovascularization (CNV). Because photosensitivity can occur with photosensitizers, it is important for ophthalmologists providing verteporfin therapy to understand its time course and duration, as well as the incidence of photosensitivity reactions.
Data were obtained from three sources: 1) the time course of skin photosensitivity in 17 volunteers by measuring erythema/edema over time after verteporfin, using red light exposure; 2) the duration of skin photosensitivity in 30 patients with skin cancer by exposing skin to simulated solar light and calculating the daily minimal erythematous dose; and 3) the incidences of photosensitivity reactions as recorded in three phase III trials in patients with CNV secondary to age-related macular degeneration or pathologic myopia who received the regimen of verteporfin therapy currently approved by regulatory authorities (infusion of 6 mg/m2 body surface area).
Results: 1) Skin photosensitivity was high at the first timepoint of 1.5 hours after dosing and decreased rapidly thereafter; 2) the duration of skin photosensitivity was dose dependent, ranging from 2.0 to 6.7 days at 6 to 20 mg/m2, respectively (mean of 2 days at a dose of 6 mg/m2); and 3) photosensitivity reactions occurred in only 2.2% of patients in the phase III trials, including two severe events, one secondary to extravasation. All treatment-related reactions in the phase III trials occurred within the first 2 days after dosing, with the exception of two mild reactions and one moderate reaction that occurred 3 days after treatment.Conclusions: Verteporfin is associated with short-lived photosensitivity and a low incidence of photosensitivity reactions in clinical trials, most of which could probably have been avoided by adherence to protocol instructions for skin protection
Posted by M.Miraftab MD,
Posted by mmiraftab at 10:33 PM
Effect of technique on intraocular pressure after combined cataract and glaucoma surgery
Ophthalmology
Henry D. Jampel, MD, MHS*1, Hospital, 600 N. Wolfe Street, Baltimore, MD 21287., US
We searched the literature to identify articles addressing the management of patients with coexisting cataract and glaucoma. We search for ansewring this question "Which is better for patients with coexisting cataract and glaucoma" Phacoemulsification or nuclear expression? Single-site or two-site combined cataract and glaucoma surgery? Combined procedures or staged surgery (glaucoma surgery first, followed by cataract extraction)? Combined procedures using trabeculectomy or combined procedures using other types of glaucoma surgery? The preponderance of evidence from the literature suggests a small (2-4 mmHg) benefit from the use of mitomycin-C (MMC), but not 5-fluorouracil (5-FU), in combined cataract and glaucoma surgery (evidence grade B). Two-site surgery provides slightly lower (1-3 mmHg) intraocular pressure (IOP) than one-site surgery (evidence grade C), and IOP is lowered more (1-3 mmHg) by phacoemulsification than by nuclear expression in combined procedures (evidence grade C). There is insufficient evidence to conclude either that staged or combined procedures give better results or that alternative glaucoma procedures are superior to trabeculectomy in combined procedures. CONCLUSIONS: In the literature on surgical techniques and adjuvants used in the management of coexisting cataract and glaucoma, the strongest evidence of efficacy exists for using MMC, separating the incisions for cataract and glaucoma surgery, and removing the nucleus by phacoemulsification.
Posted by M.Tabrizi.MD
Posted by at 11:24 AM
January 05, 2003
Severe corneal lesions after LASIK are not stage 4 DLK
OCULAR SURGERY NEWS 1/1/03
LOS ANGELES — A severe white central lesion appearing on the cornea within the first few days following LASIK is often mistaken for stage 4 diffuse lamellar keratitis, according to a surgeon here.What people are mistakenly calling stage 4 DLK is actually not a form of DLK but a toxic reaction he has dubbed central toxic keratopathy.DLK manifests as a diffuse inflammation confined to the LASIK interface. It is marked by accumulation of inflammatory cells and can be effectively treated with steroids. However, central toxic keratopathy (CTK) is focal rather than diffuse. It typically affects the central part of the ablation zone, is not confined to the interface and typically moves posteriorly into the stroma, often to the endothelium. Dr. Maloney said he is not sure what causes CTK, but he believes it is a toxic effect on the cornea, possibly caused by photoactivation of Betadine (povidone-iodine 10%, Purdue Frederick) by the excimer laser, which creates damaging free radicals.CTK is also characterized by marked striae in the flap, which appear as clear zones in the whitish opacity.Because there is no treatment for the disorder, prevention is key to its management. Dr. Maloney said surgeons should take precautions to ensure nothing potentially toxic, particularly Betadine, gets under the flap and recommended copious irrigation of the ocular surface before making the microkeratome cut.
Posted by M.Miraftab MD
Posted by at 11:50 PM
Prognosticate the future viability of new cataract surgery technologies
Eyeworld,January,2003
Posted by M.Khanlary MD
Posted by at 11:29 PM
Endoscopic cyclophotocoagulation comes of age
Eyeworld,January,2003
Endoscopic cyclophotocoagulation (ECP) has now come upon the scene as the first controlled means of surgically reducing inflow. Developed by Martin Uram, MD, associate attending physician, Manhattan Eye, Ear and Throat Hospital, New York, and recently acquired by Medtronic, ECP allows photocoagulation of the ciliary body epithelium under direct endoscopic visualization. Initially evaluated as part of a combined procedure with phacoemulsification and intraocular lens implantation, the procedure is equally applicable to pseudophakic patients with uncontrolled intraocular pressure. The ECP probe features a light pipe with 110ş illumination, an endoscope with a 10,000-pixel fiber bundle, and a 2-watt 810-nm diode laser delivery system with a 640-nm diode laser aiming beam, all contained within a 20-gauge instrument.
posted by M.Khanlari MD,
Posted by at 11:10 PM
Computer Glasses for Blurred Vision and Other CVS Symptoms
By Gina White; reviewed by James E. Sheedy, O.D., Ph.D.
Many people suffering from blurred vision at the computer are in their 40s or older: the problem is that your eye is getting older (presbyopia). You probably only notice this problem at the computer, because your monitor falls into the intermediate zone of your vision (as opposed to near or far), which you ordinarily don't use much.
Read more...
Posted by M.Miraftab MD,
Posted by mmiraftab at 11:09 PM
Keratoconus-like Topographic Changes in Keratoconjunctivitis Sicca
Cornea 2003; 22(1):22-24
Cintia S. de Paiva, M.D.; Lindsey D. Harris, M.D.; Stephen C. Pflugfelder, M.D.
Describe a case of inferior corneal steepening with a keratoconus-like pattern in a patient with nocturnal lagophthalmos and aqueous tear deficiency (ATD).
Axial videokeratoscopy showed asymmetric inferior corneal steepening in the right eye. The surface regularity index (SRI), surface asymmetry index (SAI), and the simulated keratometric cylinder change (CYL) were 1.05, 5.05, and 0.75, respectively. The keratoconus screening indices were as follows for the right eye: Klyce/Maeda index of 95% similarity (clinical keratoconus interpreted) and Smolek/Klyce index of 23.09% severity (keratoconus suspect interpreted). Ultrasound pachymetric mapping showed a normal central corneal thickness. We found a similar topographic pattern of keratoconus in seven eyes of 74 dry eye patients who were previously evaluated with the Tomey TMS-2N.
Therefore chronic ocular desiccation and aqueous tear deficiency can produce inferior corneal steepening and high astigmatism resembling keratoconus.
Posted by M.Miraftab MD,
Posted by mmiraftab at 10:30 PM
LASIK does not affect IOP readings in mild, moderate myopes
OSN,Dec,2002
NEW HAVEN, Conn. — LASIK did not cause significant intraocular pressure changes in patients with mild to moderate myopia, according to Roya Vakili, MD, and colleagues. These findings are in contrast to earlier reports of significant reductions in measured IOP after LASIK surgery for high myopia. The study authors suggest that further study is needed to determine if there is a critical amount of corneal change needed to effect a significant change in IOP. Dr. Vakili and colleagues here at Yale-New Haven Eye Laser Center obtained preoperative and postoperative IOP measurements on 66 eyes of 34 patients undergoing LASIK. Patients had a mean preop refractive error of –5.66 D. The researchers took IOP measurements with Goldmann applanation tonometry, Tono-Pen and pneumatonometry. Central corneal thickness, keratometric and astigmatic measurements were also taken preop and postop. Linear regression was used to correlate IOP measurements with degree of myopia corrected, astigmatism and central corneal thickness both before and after LASIK. The reduction in central corneal thickness after LASIK was statistically significant (P < .0001). Neither Goldmann tonometry nor Tono-Pen measurement showed a statistically significant change in mean IOP after LASIK. Pneumatonometry showed a small but statistically significant decrease in IOP.
posted by shakiba ebadollahi MD
Posted by at 07:47 PM
Ultra-thin lens reveals mystery accommodation
Eurotimes, Dec, 2002
Near visual acuity was 20/25 without correction and 20/27 with best correction for distance. All achieved a BCVA for near of 20/20 or better with mean add of 1.9 D, Dr Alió reported. "We did have a surprise finding in the good near visual acuity achieved with BCVA. This lens probably provides some accommodation and this needs to be confirmed because it may be an additional advantage of this technology," Dr Alió reported.
Posted by: S.Aliakbari MD
Posted by at 03:13 PM
TREATMENT OF POLYPOIDAL CHOROIDAL VASCULOPATHY WITH PHOTODYNAMIC THERAPY
Retina,dec,2002
Subfoveal PCV has no proven method of treatment. Although the follow-up time and the number of patients in this pilot study were limited, the encouraging results and lack of complications suggest that further study is indicated.
posted by M.Riazi
Posted by at 12:04 AM
January 04, 2003
PERIPHERAL RETINOSCHISIS AND EXUDATIVE RETINAL DETACHMENT IN PARS PLANITIS
Retina,Dec,2002
Patients with pars planitis may present with bullous retinoschisis and/or exudative retinal detachment. These findings may be related to a Coats disease-like vascular response (telangiectatic vessels and vasoproliferative tumors) secondary to chronic inflammation. Treatment of the vascular leakage tended to result in resolution of the detachment and/or schisis.
posted by M.Riazi
Posted by at 11:50 PM
<">Toric phakic intraocular lens, European multicenter study
Ophthalmology (2003) 110: 150-162
Seventy eyes of 53 patients (mean, 35 years; range, 22–59 years) with preoperative spherical equivalent between +6.50 and -21.25 diopters (D) and cylinder between 1.50 and 7.25 D were divided into group A, myopia (n = 48), with an average preoperative spherical equivalent of -8.90 ± 4.52 D, and group B, hyperopia (n = 22), with an average preoperative spherical equivalent of +3.25 ± 1.98 D. No eyes in either group experienced a loss in BSCVA, and 46 eyes gained 1 or more lines of their preoperative BSCVA. In 62 eyes (88.6%), UCVA was 20/40 or better. There was a significant reduction in spherical errors and astigmatism in all cases after surgery. All eyes of both groups were within ±1.00 D of target refraction, and 51 eyes (72.9%) were within ±0.50 D of target refraction. There was a 4.5% mean total loss of ECC during the first 6 months. No serious complications were observed. Overall patient satisfaction was very high.
posted by A.Gholaminejad MD
Posted by at 11:49 PM
Macular pucker removal with and without internal limiting membrane peeling: pilot study
Ophthalmology,Dec.2002
This pilot study provides evidence that peeling of the ILM during macular pucker surgery may not have deleterious effects
posted by M.Riazi MD
Posted by at 11:37 PM
Changes in optic nerve head blood flow after therapeutic intraocular pressure reduction in glaucoma patients and ocular hypertensives
0phthalmology,December,2002
For a similar percentage of IOP reduction, OAG patients had a statistically significant improvement of blood flow in the neuroretinal rim of the ONH, whereas OHT patients did not demonstrate such a change. Peripapillary retinal blood flow, expected to be affected less in glaucoma, remained stable in both groups. In addition to indicating a response to therapy in OAG patients, the reported changes in rim perfusion suggest that ONH autoregulation may be defective in OAG while intact in OHT.
Posted by M.Khanlari MD,
Posted by mehdi khanlari at 10:08 PM
Are All Aberrations Equal?
JOURNAL OF REFRACTIVE SURGERY Vol. 18 No. 5 September/October 2002
To determine for a fixed RMS error (25 µm, over a 6-mm pupil) how each mode of the normalized Zernike polynomial (second through the fourth radial order) affects high and low contrast logMAR visual acuity.Three healthy volunteers served as subjects. CTView was used to generate optically aberrated logMAR charts. Accommodation was paralyzed and pupils dilated. The foveal achromatic axis of the eye was aligned to a 3-mm pupil and the eye was optimally refracted. Aberrated acuity charts were read until five letters were missed. Data were normalized for each subject to the acuity obtained by reading unaberrated charts and plotted as letters lost as a function of Zernike mode.Defocus decreased letter acuity more than astigmatism . Coma decreased acuity more than trefoil . Spherical aberration and secondary astigmatism decreased acuity much more than quadrafoil .
1. For an equal amount of RMS error not all coefficients of the Zernike polynomial induce equivalent losses in high and low contrast logMAR acuity
2. Wavefront error concentrated near the center of the pyramid adversely affects visual acuity more than modes near the edge of the pyramid.
3. Large changes in chart appearance are not reflected in equally large decreases in visual performance (ie, subjects could correctly identify highly aberrated letters).
4. Interactions between modes complicate weighting each Zernike mode for visual impact.
Posted by M.Khanlari MD,
Posted by mehdi khanlari at 03:29 PM
Retinal Detachment in Myopic Eyes After Laser in situ Keratomileusis
JOURNAL OF REFRACTIVE SURGERY Vol. 18 No. 6 November/December 2002
J. Fernando Arevalo, MD; Ernesto Ramirez, MD; Enrique Suarez, MD; Rafael Cortez, MD; Gema Ramirez, MD; Juan B. Yepez, MD
To report the characteristics and surgical outcomes of rhegmatogenous retinal detachments in myopic eyes after laser in situ keratomileusis (LASIK).Clinical charts of patients that developed rhegmatogenous retinal detachment after LASIK were reviewed. Surgery to repair rhegmatogenous retinal detachment was performed in 31 eyes (mean follow-up of 14 months after vitreo-retinal surgery). A total of 38,823 eyes underwent surgical correction of myopia from -0.75 to -29.00 D (mean -6.00 D). Thirty-three eyes (27 patients; frequency .08%) developed rhegmatogenous retinal detachment after LASIK; detachments occurred between 12 days and 60 months (mean 16.3 mo) after LASIK. Eyes that developed a rhegmatogenous retinal detachment had a mean -8.75 D before LASIK. Most rhegmatogenous retinal detachment and retinal breaks occurred in the temporal quadrants (71.1%). Final best spectacle-corrected visual acuity (BSCVA) of 20/40 or better was obtained in 38.7% of the 31 eyes (two patients refused surgery). Poor final visual acuity (20/200 or worse) occurred in 22.6% of eyes.
Posted by M.Khanlari MD,
Posted by mehdi khanlari at 03:16 PM
A New Intraocular Lens Design to Reduce Spherical Aberration of Pseudophakic Eyes
JOURNAL OF REFRACTIVE SURGERY Vol. 18 No. 6 November/December 2002
Jack T. Holladay, MD; Patricia A. Piers, MSc; Gabor Koranyi, MD; Marrie van der Mooren, MSc; N.E. Sverker Norrby, PhD
The aim of this study was to design and evaluate in the laboratory a new intraocular lens (IOL) intended to provide superior ocular optical quality by reducing spherical aberration.Corneal topography measurements were performed on 71 cataract patients using an Orbscan I. The measured corneal surface shapes were used to determine the wavefront aberration of each cornea. A model cornea was then designed to reproduce the measured average spherical aberration. This model cornea was used to design IOLs having a fixed amount of negative spherical aberration that partially compensates for the average positive spherical aberration of the cornea. Theoretical and physical eye models were used to assess the expected improvement in optical quality of an eye implanted with this lens. Measurements of optical quality provided evidence that if this modified prolate IOL was centered within 0.4 mm and tilted less than 7 degrees, it would exceed the optical performance of a conventional spherical IOL. This improvement occurred without an apparent loss in depth of focus.A new IOL with a prolate anterior surface, designed to partially compensate for the average spherical aberration of the cornea, is intended to improve the ocular optical quality of pseudophakic patients. [J Refract Surg 2002;18: 683-691]
Posted by M.Khanlari MD
Posted by mehdi khanlari at 03:11 PM
Intracapsular method shortens length of cataract surgery
Ophthalmology Times December 1, 2002
Nice, France-Intracapsular cataract emulsification (ICCEM) is a promising method that simplifies and shortens cataract removal compared with phacoemulsification or extracapsular cataract extraction. "ICCEM uses heat-free, high-speed rotary-impeller technology to emulsify the cataract content within the lens capsule. The rotary impeller emulsifies the nucleus and the cortex in less than 1 minute and enables its removal by simple irrigation-aspiration (I/A).This process is done through a 1-mm capsulotomy in the anterior capsule.The freezing element of the CATAREV tool creates a thermostatically controlled, round ice ring around the capsulotomy. This technology enables a significant intracapsular pressure increase without capsular rupture at the capsulotomy site because of a special collar at the device tip that generates controlled freeze-grip to the capsulotomy edge. The freeze grip enables even distribution of the forces over the capsulotomy edge (much like capsulorhexis). Therefore, no shearing forces are presented at the capsulotomy site and capsular rupture is avoided while the intracapsular pressure is kept positive at all times
Posted by M.Khanlari MD
Posted by mehdi khanlari at 02:13 PM
Diffractive multifocal lens reduces halo complaints
Ophthalmology Times December 15, 2002
Nice, France-The diffractive/refractive, fold-able, multifocal AcrySof IOL (study model MA60D3, Alcon, Fort Worth, TX) achieves similar mean distance vision and better near vision compared with the Array multifocal SA40N IOL (AMO, Santa Ana, CA), an FDA-approved IOL. Importantly, patients reported significantly fewer complaints of halos compared with the SA40N IOL, according to Philippe Dublineau, MD. The lens is still in clinical trials and is not yet approved in the United States. The new diffractive IOL was developed to improve the percentage of light transmitted during distance vision, improve the distance visual acuity, maintain the diffractive quality of near vision, and diminish the intensity and frequency of halos. The IOL is designed such that the diffractive structure is over a 3.6-mm area of the 6-mm anterior lens surface, the steps of the diffractive structure are larger at the lens center, the step height decreases away from the lens center, and the smaller the step, the lower the proportion of energy that is directed to near focus. This process is called "apodization." When compared with the SA40N IOL, the contrast sensitivity results with the best-corrected distance visual acuity were similar at 25% and 9% of contrast in photopic or mesopic lighting. At night, patients with the MA60D3 IOL implanted registered substantially fewer complaints about halos. At 1 month after implantation, 74% had no halos, 23% had halos that were easily tolerated, and 3% described the halos as incapacitating. Patients, however, did not opt for explantation due to the quality of vision in daily activities. As usual, halos diminished with time, and at 3 months after surgery, the percentages became respectively 84%, 13%, and 3%. "Based on these results, the MA60D3 provides patients with a perfect balance between excellent distance and near visual acuity," .The contrast sensitivity results were comparable to the FDA-approved SA40N IOL. Importantly, halos occurred less frequently and were less troublesome in patients with the MA60D3 implanted than with the SA40N."
Posted by M.Khanlari MD,
Posted by at 01:13 AM
In LASIK Enhancements, Lifting Flap Gives Better Long-Term Visual Stability than Recutting
AAO, Dec, 6, 2002
San Francisco – Although LASIK enhancements can be performed safely and effectively by either lifting or recutting a corneal flap, lifting the flap appears to show better long-term stability of refractive outcomes and uncorrected acuity. This is the conclusion of a study appearing in this month’s issue of Ophthalmology, the clinical journal of the American Academy of Ophthalmology, the Eye M.D. Association.In this study, 212 eyes of 202 patients underwent myopic LASIK enhancement over a five-year period. Relifting of flaps was performed in 164 (77.4 percent) of the patients, and recutting of flaps was performed in 48 (22.6 percent). There were no significant differences in early visual outcomes between the two groups, but at one year patients who had flaps lifted had significantly better uncorrected vision (20/24.7) than those who had flaps recut (20/31.3). In addition, the group with lifted flaps had more stable refraction at one year
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Posted by M.Pakravan MD,
Posted by at 12:32 AM
January 03, 2003
Study recommends imaging for diagnosis of complex strabismus
OSN,2002
Magnetic resonance imaging or computed tomography can spot abnormalities in extraocular muscles that clinical examiniations fail to detect.In a 12-year prospective study between 1990 and 2001 funded by the National Eye Institute MRI was performed on 267 patients. For high resolution, surface coil images with a slice thickness of 1.5 mm to 3 mm were used. All coronal images were obtained while the patient was in a central gaze position. Selected cases were supplemented with eccentric gaze positions, sagittal or axial angle images,.CT scans were performed in the 56 remaining patients.All images gathered were digitally analyzed to assess the size and location of the extraocular muscles. patients had complete ophthalmological examinations & found commonly identifiable abnormalities in the sizes or structural positioning of muscles in patients with strabismus. Researchers found that 38 strabismus patients had absence or atrophy of the superior oblique (SO) muscle in SO palsy. There were also eight patients who had structural abnormalities of the trochlea or SO tendon, which are associated with Brown’s syndrome. The high resolution of the MRI showed that in SO palsy this muscle was smaller than normal muscles and did not show the normal, contractile thickening from supraduction to infraduction.Researchers found that 15 additional cases, which to be SO palsy in clinical examinations, were found to be masquerading as SO palsy.“Based on imaging, there was no abnormality of size, structure, or contractility of the SO muscle for these cases,”Additionally, 46 patients were found to have malpositioning (heterotopy) of a rectus pulley muscle, which is associated with incomitant strabismus. There were nine other patients who had an instability of the muscular pulleys.Therefore it is often necessary to perform both clinical tests and computerized scans on patients with complex strabismus to rule out all possibilities for abnormalities.
Posted by S.Chinichian MD ,
Posted by at 11:23 PM
Coronado Industries to Announce Vision Field Improvement after PNT Treatments in Glaucoma Patients
Eyeworld,december ,2002
Coronado Industries, Inc. (OTC BB:CDIK) - After five months of hands on experience with PNT (Pneumatic Trabeculoplasty) at the Arizona Glaucoma Institute, this procedure is everything it was presented to be, and more. It was a simple, safe and effective treatment for glaucoma and it is.It has been been successful in lowering the intra-ocular pressure in most of the patients treated. Also, in a majority of the treated patients, has been been successful in getting them off their medicationsl, or at the very least, greatly reducing the amount of medications needed.To date, it has not experienced any adverse side effects or complications related to this procedure. The most exciting benefit of this procedure is the percentage of patients who's vision has improved. This is documented by, before and after refractions.
Posted by M,Taheri MDP
Posted by at 07:24 PM
Photodynamic therapy using verteporfin for choroidal neovascularization in angioid streaks
American Journal of Ophthalmology, January 2003
Verteporfin for choroidal neovascularization–associated with angioid streaks does not appear to significantly alter the course of this disease with most eyes undergoing enlargement and disciform transformation of the neovascular process. However, aggressive management of these patients with biomicroscopic and fluorescein angiographic examination and timely photodynamic therapy with early retreatment when indicated may be beneficial in certain cases
Posted by M.Miraftab MD,
Posted by mmiraftab at 12:24 PM
Atopy: A Patient-specific Risk Factor for Diffuse Lamellar Keratitis
Ophthalmology, January 2003
Stephen M. Boorstein, MD, Henry J. Henk, BS, Victor M. Elner, MD, PhD
The risk of DLK in untreated atopic patients was much greater than the risk of DLK among nonatopics (odds ratio, 5.85; 95% confidence interval, 2.89–11.85; P = 0.001). However, the risk of DLK among atopic patients taking an oral systemic nonsedating histamine receptor 1 antagonist and among nonatopic patients did not differ significantly (odds ratio, 0.54; 95% confidence interval, 0.12–2.46; P = 0.43).
Conclusions: Atopy is a patient-specific risk factor for the development of DLK after primary bilateral LASIK for either myopia or myopic astigmatism. Atopic individuals benefit from preoperative treatment to minimize the incidence of DLK and the potential for visual loss.
Ophthalmology 2003;110:131–137 © 2003 by the American Academy of Ophthalmology.
Posted by M.Miraftab MD,
Posted by mmiraftab at 01:51 AM
VISX released its Star S4 laser upgrade
ophthalmology management, December 2002
which gives surgeons the capability to create PreVue lenses for the first time. The lenses, which are ablated with a planned LASIK treatment, allow patients to subjectively assess their potential result from either a standard or a custom procedure prior to undergoing surgery. Poor candidates can be screened out before they become unhappy patients.For the surgeon, ablating a PreVue lens also serves as a check of the laser and the measured wavefront. If a patient has minimal higher-order aberrations, he often will not experience improved visual acuity through the lens.
Posted by M.Miraftab MD.
Posted by mmiraftab at 01:20 AM
Tips & Techniques for Laser Phacoemulsification
ophyhalmology management,December 2002
By Mark Packer, M.D., I. Howard Fine, M.D., Richard S. Hoffman, M.D.
Laser phacoemulsification is a promising part of cataract surgery evolution. It still has limitations, including difficulty in removing dense nuclei, but our experience shows that laser phacoemulsification is gentle to the eye, producing exceptionally clear corneas and excellent uncorrected visual acuity on postoperative day one.
Posted by M.Miraftab MD.
Posted by mmiraftab at 01:09 AM
January 02, 2003
Haptic system of the 360 SE lens provides a barrier to PCO
OCULAR SURGERY NEWS EUROPE/ASIA-PACIFIC EDITION December 2002
The 360 SE from Corneal SA is a new concept that uses a capsular tension ring effect. The lens is circular, filling the capsular bag better than any other lens currently on the market. The six haptics form a circular, closed capsular tension ring and provides a barrier against posterior capsule opacification. The main difference between this lens and others is the presence of six identical loops.
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| The six haptics form a circular, closed capsular tension ring |
There are three “levels” at which PCO can be stopped. One is at the equator of the capsular bag (tension ring effect), the second is in between the equator and the IOL and the third is at the IOL-optic edge. This lens applies sharp-edge technology on both optic and haptics. Sharp-edge technology is a combination of several characteristics: a sharp edge all around the optic, even at the optic/haptic junction, an angulation to obtain contact from the optic with the posterior capsule and a constant posterior curvature of the optic.The capsular-tension-ring effect of haptics coming into contact acts to prevent posterior capsule folds and diminish the distance between the posterior capsule and the IOL. To implant the lens, the surgeon can inject it through a conventional 3.2-mm incision. As with any IOL that is angulated, the surgeon must check that the lens is correctly oriented (clockwise) before closing the injector. We could achieved our goals with the lens: perfect centration, no capsular folds, no PCO, transparent anterior capsule.
posted by Dr Taherzadeh
Posted by at 10:53 PM
Refractive procedures in 2010
OSN,3/1/2003
In a field such as refractive surgery, which often grows by revolution, a prediction over the next decade is likely to be wrong as well as embarrassing to the prognosticator. So, let’s look at what won’t be the dominant refractive procedure by 2010.First, presbyopia; maybe by 2020, but not by 2010. Although millions await a presbyopia cure, most want a physiologic cure, not an optical methodology to allow simultaneous distance and near focus. Thus, both monovision and multifocal technologies (whatever they may or will be) are inherently limited by noise or visual that is unacceptable to many patients. So these procedures will not dominate. Scleral expansion efforts promise a cure, but I remain skeptical about the actual efficacy and long-term results, as well as patient acceptance of such a surgically complex procedure. But wait until 2020. Presbyopia will be the scene of the next revolution.Next, phakic IOLs. Over the past 3 years, I have done corneal transplants on four eyes with phakic IOLs. Even if this is anomalous, a procedure to attract LASIK-like numbers will need to be absolutely safe, without any incidence of corneal decompensation, cataract or distorted pupils.Although technologies are improving and many patients (especially high refractive errors) will achieve good and safe results, to dominate the landscape phakic IOLs will need to be as easy and safe for the patient as LASIK is today, and I don’t think they will be by 2010.Thus, we are left with the excimer laser. But will it be LASIK (with a microkeratome or laser flap), LASEK, PRK, custom wavefront ablation, or intrastromal ablation? As a given, I do think that some type of optical customization is likely to be de rigueur by 2010 (whether it be current wavefront concepts or otherwise). But, what will be our modality of application? I think we will leave the LASIK flap behind and return to the surface, but with the aid of new pharmaceutical agents that will allow good early vision, comfort and standardized wound healing. Such a procedure will meet the criteria of patient acceptance necessary to dominate refractive surgery: excellent visual acuity and function for a wide range of patients, rapid rehabilitation, comfort, safety and ease.
Posted by Mansour Taherzadeh .MD
Posted by at 10:38 PM
A New Method of Calculating Intraocular Lens Power After Photorefractive Keratectomy
J Refract Surg 2002;18:720-72
To find a method of calculating intraocular lens (IOL) power that may be independent of preoperative data, in eyes that have developed a cataract after refractive surgery.Prior to and 1 month after PRK, the SRK/T formula was used to calculate IOL power in 88 eyes of 65 patients with a preoperative spherical equivalent refraction between -16.25 to +0.25 D (mean -5.39 ± 3.19 D). IOL power was calculated by utilizing the spherical equivalent refraction as target both before and after PRK. Utilizing the postoperative corneal radius measurement (R2), an underestimation of the IOL power was found. For this reason, the mean postoperative corneal radius (R3) that gave the same IOL power found before surgery was calculated for each patient. The R3/R2 ratios were plotted against the axial eye length and a linear regression formula was used to calculate R2 correcting factors that gave the new corneal radius (R4). Patients were divided into classes according to axial eye length, and the mean R3/R2 ratios for each class were calculated and used to recalculate the new mean radius (R5). IOL power for emmetropia was calculated in all patients by utilization of R3, R4, R5, the historical method, and the “true corneal power” method.Within ±0.50 D from the IOL power calculated with R3, R4 gave 35 (39.3%) IOLs, while R5 gave 40 (45.5%) IOLs; the clinical history method gave 24 (27.3%) IOLs and “true corneal power” gave 23 (26.1%) IOLs, with a statistically significant difference P<.001).Our theoretical method, based on correlation between axial eye length and corneal radius correcting factors, may represent an effective method of calculating IOL power after PRK, especially if the history of the patient is unknown.
Posted by A-Habibollahi,MD
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Posted by at 02:51 PM
A paradoxical ocular effect of brimonidine
Am J Ophthalmol 2003 Jan;135(1):102-3
Brimonidine (0.2%) is believed to lower the intraocular pressure (IOP) by reducing aqueous humor production via the stimulation of presynaptic and postsynaptic Alfa2 receptors and by enhancing uveoscleral outflow, through an additional effect on imidazoline receptors in the ciliary body. Its recognized side effects include allergy and anterior uveitis that may develop up to 15 months after the initiation of therapy. Here is a report of novel paradoxical effect of brimonidine that resulted in raised IOP, confirmed on rechallenge.
A 70-year-old Caucasian woman with normal tension glaucoma (highest known IOP 19 mm Hg in both eyes) was changed from topical beta-blockers to brimonidine because her pressures were poorly controlled at IOP of 18 mm Hg in both eyes. Twenty months later she presented with a 3-week history of sore red eyes. Examination showed bilateral marked conjuctival follicular reaction with episcleral and conjuctival injection. The IOP was 34 mm Hg in the right eye and 32 mm Hg in the left. There was no sign of intraocular inflammation, and gonioscopy was normal; brimonidine was discontinued. One-month later, her eyes were quiet, and IOP was 20 mm Hg in both eyes. Brimonidine was suspected to be responsible for the raised IOP and conjuctival reaction. The patient was rechallenged with brimonidine and reviewed after 2 weeks. She reported soreness of the eyes that developed within the first week, causing her to discontinue brimonidine 4 days prior to her appointment. Examination revealed conjuctival and episcleral injection and follicular reaction. There were no cells or flare in the anterior chamber, and IOP was 32 mm Hg in the right and 26 mm Hg in the left eye. The patient remained off brimonidine and was seen 2 weeks later. The eyes were white, with IOP dropping back to 19 mm Hg in the right and 21 mm Hg in the left eye.
The fact that there was recovery on withdrawal, absence of other identifiable causes, objective evidence of raised IOP, recurrence on rechallenge, and that the patient was not taking any other medication that could elevate the IOP suggest that it was indeed an adverse reaction to bromonidine. The possible mechanisms for this effect include reduced outflow facility owing to subclinical trabeculitis, elevation of episcleral venous pressure, or increased production of aqueous humor. Given the previous clinical evidence of idiosyncratic ocular inflammation with this drug, we suspect there was subclinical trabecular inflammation. This demonstrates that brominidine can cause raised IOP, which in this case was accompanied by its more commonly observed allergic manifestations. This patient was on monotherapy, and in the 4 years of follow-up never exhibited IOPs higher than 19 mm Hg. These two features allowed swift identification of the cause. The fact that not all patients who develop local allergic reaction to brimonidine have the therapy discontinued should lead clinicians to be alert to this paradoxical effect.
Posted by dastjerdi at 09:42 AM
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| Inserting the scleral expansion band into the eye, and a postop slit lamp view |
Accommodative amplitude was measured monocularly using a near-point push technique from both 70-cm and 30-cm starting points. At six months, investigators found a modest increase in accommodative amplitude, about 1.7 D in the surgical eye at these two testing distances. To a lesser extent, this increase was also seen in control eyes. About 50 percent gained three lines of near acuity in the operated eye at six months, while the other half had minimal to no response. There were no reports of anterior ischemia or malignant glaucoma. Adverse effects were limited to a transient elevation of intraocular pressure in one patient and misalignment of single SEI segments due to inadequate scleral pockets in three patients. Of these three, one segment was replaced.
Posted by dastjerdi at 08:51 AM
The History of Spectacles
The invention of spectacles profoundly influenced progress in the arts and sciences, yet we do not know whom to thank for this invention. Marco Polo, journeying to China in 1270, is said to have observed elderly Chinese using spectacles. The Chinese themselves claim that spectacles originated in Arabia in the 11th century.
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| Horn Spectacles, 1500 |
In the western world, the invention of spectacles is believed to have occurred between 1268-1289. Riveted spectacles to correct presbyopia (the inability to focus on objects that are near) were one of the earliest pairs invented. The wearers, mostly monks and scholars, held the lenses in front of their eyes or balanced them on their nose since any movement would send the lenses falling .The invention of the printing press in 1452 and the growing availability of books prompted the mass production of inexpensive spectacles that were sold in cities by peddlers. The middle and lower classes began wearing spectacles mounted in leather, wood, horn, bone or even light steel. The upper classes on the other hand, favored more genteel, although cumbersome, hand-held spectacles with frames of gold and silver.
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| Rigid bridge spectacles 1600 |
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| Temple Spectacles, 1750 |
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| Bifocals Spectacles, 1820 |
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| Folding Lorgnette, 1925 |
The first significant advance in frame design occurred in the 1600s with lenses fixed to a rigid bridge rather than riveted, allowing them to stay in place. Quizzing glasses, small single lenses with decorative stems, and hand-held scissors glasses, became favorites among famous individuals such as Goethe, Washington and Napoleon during the early 1700s and early 1800s. Between 1725 and 1750, a London optician designed the first temple spectacles, while Ben Franklin invented bifocals. Ornate prospect glasses, French lorgnettes and miniature spyglasses became all the rage in pre-Revolutionary France. In the late 1800s, Teddy Roosevelt and Calvin Coolidge made Pince-Nez and trifocals popular, while cylindrical lenses for astigmatism became available.
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| Colored Spectacles, 1960 |
The 20th century as a whole became a time of gradual and dramatic change in the eyewear world. Along with progress in lens acuity and frame shapes, eyewear became, and still is, a popular accessory for both men and women whether worn plain or in prescription strength.
Posted by dastjerdi at 01:12 AM
High levels of carotenoids may delay onset of cataract
OSN Supersite 12/12/02
Higher levels of lutein and zeaxanthin in the eye may help delay the onset of age-related cataract, according to a study. An inverse relationship between lens optical density and macular pigment optical density was found in the study, suggesting that lutein and zeaxanthin in the eye may retard lens aging.
posted by: M. Pakravan M.D.
Posted by at 12:45 AM
January 01, 2003
FDA Approves Cyclosporine Product for Chronic Dry Eye Therapy
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| The first and only therapy for patients with KCS |
| Recommended dosage is one drop in each eye twice a day |
| Restasis will be available in the US in early April 2003 |
Posted by dastjerdi at 04:50 PM
New macular hole surgery technique may reduce prone positioning
OCULAR SURGERY NEWS EUROPE/ASIA-PACIFIC EDITION January 2003
LAUSANNE, Switzerland – A new surgical technique for the closure of stage III-IV idiopathic macular hole may reduce the time of prone positioning to only 12 hours.
The usual procedure for treating macular hole is:“To treat both the macular hole and the retina, we must performe a standard procedure with pars plana vitrectomy, peeling of the internal limiting membrane in the macular region using ICG and then filling the eye with SF6 gas. The patient then placed in a prone position for a time that was expected to be the usual 7 days. However, already the following day not only was the retina attached, but to our great astonishment the macular hole had also completely closed. The patient left the hospital without any special instructions on the position she should keep, and the macular hole stayed closed during the follow-up.”But there is a new surgical technique presented by DR.Gonvers: " Inducing retinal detachment" He thought we should try to detach the retina in the posterior pole to facilitate the closure of large idiopathic macular holes. This necessitated the development of a new surgical approach.In four eyes with a stage IV macular hole, following pars plana vitrectomy and ILM peeling under ICG staining, the posterior retina was detached with a subretinal infusor developed by Dr. Gonvers and colleagues a few years before.
“The instrument has a central opening for the infusion of fluid, and small openings in the periphery for atraumatic aspiration of the retina,”
posted by k.h.jalali,MD
Posted by at 03:00 PM
Topical and systemic steroids effective for severe DLK
Ocular Surgery News
SAN FRANCISCO — Combined topical and oral corticosteroids effectively manage severe cases of diffuse lamellar keratitis and may be a convenient alternative to flap lifting and interface irrigation, according to a study presented here. The outbreak he experienced resulted in a 4% incidence of DLK (40 cases). Oral prednisolone and topical Pred Forte (prednisone acetate, Allergan) were used in all patients who developed stage 3 DLK and those patients who exhibited stage 2 DLK on the first postoperative day and thus appeared at risk for progressing to stage 3. According to Dr. Hoffman, 55% of all eyes treated for DLK received oral steroids and the majority of these patients were started on steroids by the fourth postoperative day. Twenty-five percent of the DLK patients did not progress past stage 1. Stage two was the most common maximum DLK stage reached, with 48% of patients progressing to it. Seventeen percent of patients progressed to stage 3. No patients experienced corneal scarring or a loss of best corrected visual acuity
Posted by A. Habibollahi MD.
Posted by at 01:55 PM
Incidence of Lens Opacities and Clinically Significant Cataracts With the Implantabl Contact Lens
[J Refract Surg 2002;18:673-682]
To compare the incidence of anterior subcapsular lens opacities, clinically significant cataracts, secondary lens-related surgical reinterventions, and vaulting characteristics of the now discontinued V3 and currently used V4 STAAR Surgical Implantable Contact Lens (ICL) phakic intraocular lens designs, 87 eyes were implanted with the V3 and 523 eyes with the V4 ICL as part of the U.S. FDA clinical trial for myopia. LOCS III assessment of lens opacities, clinically significant cataract, ICL vaulting (clearance between ICL and crystalline lens), and secondary ICL-related surgeries were the main outcome measures.Incidence of anterior subcapsular opacities was significantly higher with the V3 vs. V4 ICL (12.6% vs. 2.9%, P<.001). The difference was largely due to the higher rate of late-appearing opacities The V3 group had a greater proportion of eyes with poor vault (23.6% vs. 4.3%, P<.001) and the presence of poor vault was highly associated with the development of late anterior subcapsular opacities (P<.001). Clinically significant cataract was more frequent in the V3 vs. V4 ICL (9.2% vs. 0.8%, P<.001), as was cataract extraction (6.9% vs. 0.2%, P<.001), and need for ICL replacement (5.7% vs. 1.1%, P<.001). Differences in opacity rate between the V3 and V4 designs were not due to differences in postoperative follow-up.Implantation of the currently used V4 STAAR Surgical model ICL resulted in significantly less anterior subcapsular opacities, clinically significant cataracts, and secondary ICL-related surgery.
Posted By: A. Habibollahi MD.
Posted by at 01:39 PM
Sleep exams simplify diagnosis of ocular myasthenia
OSN,December,2002
PHILADELPHIA — New, simple and noninvasive tests for spotting and diagnosing ocular myasthenia can be performed in your office, according to a neuro-ophthalmologist in practice here. The classic, traditional office test is a Tensilon test.The Tensilon (edrophonium chloride, ICN Pharmaceuticals) test is usually performed when a patient shows a measurable degree of ptosis or a large motility defect. Typically, a weakness caused by myasthenia will improve after administration of the drug. In the Tensilon test, the edrophonium chloride is given intravenously. However, sensitive patients — such as children and infants — are often incompatible with the intravenous mode of therapy, he said. To avoid these complications, Dr. Moster recommends the sleep and ice-pack tests because they are noninvasive and safe and can be performed in a physician’s office. In the sleep test, you measure the deficit. Allow patients to sleep or rest with their eyes closed in a dark room for 30 minutes. If, when the patient gets up, there is resolution or notable improvement of symptoms, you know you have a case of myasthenia on your hands,” he said. Ophthalmologists can also use an ice test to measure ptosis. “Put an ice pack on the patient’s eyelid for 2 minutes. If ptosis is improved by 2 mm or more after ice, you have a case of myasthenia,” he said.
According to Dr. Moster, the ice test is 80% sensitive and even more specific. So if the patient’s ptosis responds positively to the ice-pack treatment, it is likely that the patient has myasthenia.
posted by A.Farahi , MD
Posted by at 12:24 AM