Ophthalmology Review

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August 31, 2003

Design issues can affect PCO in one-piece lenses
OSN August 2003

SAN FRANCISCO – Some one-piece IOL designs may protect better against posterior capsular opacification than others, recent studies suggest.The classic one-piece IOL design studied in the rabbit experiment, showing the round tapered optic edge at the optic-haptic junction.The re-engineered prototype IOL, showing the 360° square edge around the lens optic, eliminating the potential “Achilles' heel.”Now David J. Apple, MD, and colleagues are testing the hypothesis that the square edge must be continuous for 360° around the lens for the PCO barrier to be most effective. Dr. Apple, have noted that some one-piece foldable lenses have optic-haptic junctions where the edge is not square. This region migh therefore represent a pathway where cellular growth onto the posterior surface of the IOL can occur, they hypothesize.
Dr. Apple said several one-piece foldable IOL designs are now being tested, not only in large clinical studies but also in lab studies, to ascertain their effectiveness against PCO.“We’ve come up with a new theory that lenses with incomplete square edges may have a potential weakness or an “Achilles’ heel” right at the haptic-optic junction where the haptic meets the optic, where the protection of the square edge is lacking,”

Posted by mehdi khanlari at 11:23 PM

New Generation of Capsular Tension Ring’
Producer: Christophe Chassain, M.D.
Eyeworld August 2003

“New Generation of Capsular Tension Ring,” produced by Christophe Chassain, M.D., of Montpellier, France, presents a new idea about capsular tension rings — all such rings are rigid, except for a new device, the Flexiring, named for its obvious flexibility. Chassain’s concept recently won first place in the Cataract/Implant Surgery category at the ASCRS/Alcon Film Festival in San Francisco.“[The difference between the rings] is the same kind of difference that you can make between rigid IOLs and soft IOLs,” he said. However, there are some differences in the results. “[The Flexiring] seems more efficient for the protection of capsulophimosis than standard tension rings, but as it is less rigid, it is not yet indicated when there is a zonular desinsertion,” Chassain said. Study of the ring continues.Chassain said his goal for the film was “to compare the standard tension rings and the capsular bending ring (a specific anti-PCO ring) with the Flexiring. I wanted to show how it could be difficult and dangerous to use a standard tension ring.” The greatest advantage of the Flexiring is that it is very smooth and easy to insert in the capsular bag, he said. In the film, Chassain discusses the role of all the capsular rings in the prevention of PCO. Click here to view the video!

Posted by mehdi khanlari at 12:42 PM

Researchers develop new gel technique to improve eyesight
Eyeworld August 2003

Researchers at the Vision Cooperative Research Center in Australia have developed a new technique to improve eyesight, which involves replacing the contents of the lens with a soft polymer gel. Scientists hope to begin trials next year. The technique will initially be used to improve cataract surgery in elderly patients. Tests on animals have been promising so far, he said. Inserting the gel would be similar to cataract surgery but the lens would not be replaced. The contents will be sucked out by a tiny incision in the cornea and replaced with the gel. The procedure could last as short of a time as 15 minutes

Posted by mehdi khanlari at 12:14 PM

August 29, 2003

Lacquer crack formation after LASIK
Ophthalmology August 2003
A 37-year-old female patient with high myopia in both eyes attended our clinic to have her myopia surgically corrected. The spherical equivalent (SE) was -10.00 diopters (D) in her right eye and -8.25 D in her left eye. Preoperative best-corrected visual acuity (BCVA) was 20/32 in the right eye and 20/28 in the left. No myopic macular alterations were present in either eye before surgery. Corneal pachimetry revealed insufficient corneal thickness (520 µm for the right eye and 500 µm for the left) to be corrected with our laser (Technolas 217-C, Chiron Vision, St. Louis, MO). A phakic intraocular anterior chamber lens (Morcher GmbH, Stuttgart, Germany) implantation was performed in August 2001. The postoperative period was uneventful. By October 2001, BCVA was 20/25 (SE = -1.75) in the right eye and 20/25 (SE = -0.75) in the left. The patient asked for further correction of her myopic defect, which was performed by LASIK without complications on December 11, 2001. She described loss of vision in the same day after LASIK in her right eye. BCVA was 20/50 (SE = 0.00) in the right eye and 20/28 (SE = 0.00) in the left. Indirect ophthalmoscopy disclosed a macular hemorrhage and a lacquer crack . Fluorescein angiography showed no choroidal neovascularization. No treatment was performed, and the patient was kept under observation. Three months later BCVA was 20/25 (SE = -0.50) and the macular hemorrhage had disappeared completely, leaving a residual lacquer crack Reasons for the development of lacquer cracks remain unclear. They may be the healed mechanical breaks of retinal pigment epithelium (RPE), Bruch's membrane, and choriocapillaris complex and have been related to a weak Bruch's membrane. It is believed that lacquer cracks as well as other macular degenerative changes in pathologic myopia are caused by mechanical stretching of the retina and choroid within the posterior staphyloma.
The occurrence or extension of a lacquer crack can be associated with a macular hemorrhage that may occur in the absence of subretinal neovascularization. In highly myopic eyes subretinal hemorrhages and lacquer cracks are often found simultaneously. Klein and Curtin reported subretinal bleeding in 33% of lacquer cracks.

Different hypotheses have tried to explain the posterior segment pathology after LASIK, such as mechanical stress caused by the intraocular pressure (IOP) elevation produced by the pneumatic suction ring, which may induce tangential stress at the posterior segment and even cause a rupture in Bruch's membrane. Another cause of stress might be the impact of excimer laser energy on the cornea producing stress waves along the axis of the eye. Stress wave amplitudes during photoablation reach a maximal pressure focus of up to 100 atmospheres located in the posterior lens and anterior vitreous and then decrease to <10 atmospheres at the retina.

In this case subretinal bleeding signals the development of a rupture of Bruch's membrane. Increased IOP and, less probably, the wave shock during laser ablation cause significant mechanical stress on fragile highly myopic eyes.

To our knowledge new lacquer cracks have not been previously described in myopic patients immediately after LASIK. Macular hemorrhages after LASIK correction of high spherical defects (-12 to -25.87 D) are often associated with poor preoperative BCVA, thinning of RPE and previous choroidal neovascularization, and Fuchs' spots. Their appearance after LASIK can be easily explained in terms of the high probability of highly myopic eyes developing lacquer cracks with time, and in many cases result in poor visual outcome. This may be due, in part, to the association of lacquer cracks with highly myopic patients in whom LASIK is nowadays not indicated as a primary surgical procedure.

This is the only case of a lacquer crack appearing in a large series of myopic patients undergoing LASIK in our clinic (more than 9000 eyes). We have been able to establish a definite relationship between LASIK and the development of lacquer cracks and subretinal hemorrhages, since it appeared, and the patient described vision loss immediately after the procedure. Ohno-Matsui considers that lacquer cracks are often underdiagnosed because of their small size and the difficulty of detecting them in myopic fundi.8

Lacquer cracks often lead to poor visual outcomes because of choroidal neovascularization and macular atrophy in pathologic myopia. The risk of developing lacquer cracks in highly myopic patients corrected by LASIK, though uncommon, must be kept in mind. This is true especially in highly myopic patients with myopic retinopathy in whom LASIK could be used to correct residual defects after posterior chamber or phakic intraocular lens implantation

Posted by mmiraftab at 03:03 PM

Corneal Graft Rejection After Posterior Capsulotomy
Asian Journal of Ophthalmology

This report reviews 3 patients with pseudophakia who developed corneal graft rejection after undergoing Q-switched neodymium:yttrium-aluminum- garnet laser posterior capsulotomy for posterior capsular opacification. All patients had previously undergone a combined procedure of extracapsular cataract extraction with posterior chamber intraocular lens implantation in the capsular bag. Both the beneficial optical effects and the potential adverse effects should be carefully considered prior to performing neodymium:yttrium-aluminum-garnet laser posterior capsulotomy in patients with corneal graft. It is suggested that all efforts should be made for meticulous control and early intensive treatment of the inflammation and the intraocular pressure increment in patients with pseudophakia with corneal graft who require neodymium:yttrium-aluminum-garnet laser capsulotomies to improve the outcome of corneal grafts.

Posted by mehdi khanlari at 01:29 PM

The relationship between iris color, hair color, and skin sun sensitivity and the 10-year incidence of age-related maculopathy
Ophthalmology August 2003

When controlling for age and gender, people with brown eyes were significantly more likely to develop soft indistinct drusen (risk ratio [RR], 1.53; 95% confidence interval [CI], 1.19–1.97; P < 0.01) than were people with blue eyes. However, people with brown eyes were significantly less likely to develop retinal pigment epithelial depigmentation (RR, 0.58; 95% CI, 0.41–0.82; P < 0.01) than were people with blue eyes. When compared with persons with blond hair, persons with brown hair were at decreased risk of developing pigmentary abnormalities (RR, 0.73; 95% CI, 0.53–1.00; P = 0.05). Iris color, hair color, and skin sun sensitivity were not associated with the development of late ARM.
CONCLUSION: Iris color and hair color were found to be associated with the 10-year incidence of pigmentary abnormalities. Iris color seems to be inconsistently related to the 10-year incidence of early ARM lesions and the progression of ARM.

Posted by mehdi khanlari at 01:22 PM

Behçet’s disease :new finding
BJO sep 2003

Behçet’s disease (BD) is characterised by recurrent episodes of orogenital aphthae, systemic vasculitis, and systemic and retinal venous thrombosis. An association between HLA-B51 and BD was first identified over 20 years ago, but recently identified gene associations implicate regions both within and without the MHC in the immunological events underlying the lesions in BD. These include allelic variants within the tumour necrosis factor gene region and within the MHC class I chain related gene region, the factor V Leiden mutation, which is associated with retinal vascular occlusion, and alleles of the intercellular adhesion molecule gene. No single causative gene for BD has emerged; the evidence indicates that the underlying immune events in BD are triggered by a microbial antigen and subsequently driven by genetic influences which control leucocyte behaviour and the coagulation pathways. Knowledge of these risk factors may permit a more accurate prognosis for a given patient, and identify new pathways for more targeted intervention than is currently available.

Posted by mehdi khanlari at 01:18 PM

Inferior corneal steepening after a partial flap without laser ablation mimicking corneal ectasia
Journal of Cataract & Refractive Surgery Volume 29, Issue 8 , August 2003, Pages 1626-1629
We report a patient with inferior steepening mimicking corneal ectasia that developed after 2 incomplete microkeratome cuts (partial or short flap) without laser ablation

Posted by mmiraftab at 02:02 AM

Interaction between aberrations to improve or reduce visual performance
Journal of Cataract & Refractive Surgery Volume 29, Issue 8 , August 2003, Pages 1487-1495
Raymond A. Applegate
Methods:Subjects read aberrated and unaberrated visual acuity charts 3 times. Each aberrated chart was produced by convolving an aberrated point-spread function with an unaberrated acuity chart. Point-spread functions were defined by 4 pairs of Zernike modes. For each pair, 9 combinations were used, ranging from all aberration being loaded into the first mode to all aberration being loaded into the second mode. The root mean square (RMS) wavefront error always totaled 0.25 m (6.0 mm pupil), a level similar to the aberration induced by traditional flying small-spot laser refractive surgeries.
Results:For all conditions (except the unaberrated charts), visual acuity decreased. Acuity varied significantly depending on which modes were mixed and the relative contribution of each mode. Modes 2 radial orders apart and having the same sign and angular frequency tended to combine to increase visual acuity. Modes within the same radial order tended to combine to decrease acuity.
Conclusions:For low levels of aberration, the RMS wavefront error is not a good predictor of visual acuity. Clinically, it is important to define how aberrations interact to optimize visual performance. New metrics of optical/neural performance that correlate better with clinical measures of visual performance need to be adopted or developed, as well as new clinically viable measures of visual performance that are sensitive to subtle changes in optical performance.

Posted by mmiraftab at 01:52 AM

August 27, 2003

Corneal aberrometer linked to laser shows promise for quality customized ablation
OCULAR SURGERY NEWS EUROPE/ASIA-PACIFIC EDITION June 2003
The CSO/Schwind system focuses on corneal aberrations, translating topographic maps into aberrometric maps.
A new system for customized ablation linking topography, aberrometry and laser is proving effective in treating corneal irregularities induced by previous surgery, “It’s an entirely new concept. Topographic maps are translated into aberrometric maps, which are able to give a precise image of what corneal irregularities produce in terms of image distortion,” said Ugo Cimberle, MD, at the winter meeting of the European Society of Cataract and Refractive Surgeons.The analysis of the corneal aberrometer focuses on the cornea rather than the entire eye, and this is the best and most reasonable choice possible,The cornea is the principal lens of our eye. Most image distortions come from there, and we work with the laser on its surface. Correcting aberrations on the cornea produced by other parts of the eye is, in my opinion, extremely improper, because it induces irregularities on the cornea and alters its natural conformation. We end up with a cornea that is worse rather than better,The system consists of the Eye-top (CSO), linked to the Esiris excimer laser (Schwind) through the ORK-W (optimized refractive keratectomy) program.

Posted by mmiraftab at 08:42 AM

August 26, 2003

MULTIFOCAL ELECTRORETINOGRAPHY EVALUATION FOR EARLY DETECTION OF RETINAL DYSFUNCTION IN PATIENTS TAKING HYDROXYCHLOROQUINE
Retina Volume 23(4) August 2003 pp 503-512
Results: The patient with toxic maculopathy and one patient without toxicity had multiple areas of decreased retinal responses bilaterally (classic m-sequence). The patient with toxicity and another three patients without toxicity presented with multiple areas of decreased retinal function in both eyes with the second-order component of the MF0F0 paradigm. Repeated recordings of 1 patient 8 months after the initial recording demonstrated evidence for reproducibility of the second-order adaptive effects.

Conclusion: Clinically asymptomatic patients receiving hydroxychloroquine treatment can have substantial local decreases in their retinal function, as reflected by the changes in mfERG recordings, possibly indicating a preclinical stage of drug-related toxicity.

Posted by mriazi at 10:12 PM

August 25, 2003

Phase 2 data on Lucentis promising for AMD
In a study, 64 patients with neovascular age-related macular degeneration were enrolled in the study of the anti-angiogenesis drug [Lucentis or ranibizumab (Anti-VEGF), Genentech].The patients presented with minimally classic choroidal neovascularization (CNV), predominantly classic CNV or active lesions following photodynamic therapy. Twenty-five patients received a dosage or four Lucentis injections of 300 µm each, 28 patients received 500 µm of Lucentis in four escalating dosages and 11 received usual care.The patients in both treatment groups achieved a mean improvement in visual acuity of nine letters at the end of 98 days.Regarding the safety of the drug, “Lucentis was well tolerated,”, transient inflammation was the most common side effect. Other complications, including cases of endophthalmitis, central retinal vein occlusion and uveitis, resolved completely.

Posted by kjalali at 07:30 PM

Increased iron levels in macula associated with AMD

In a study,postmortem eyes affected by either nonexudative or exudative AMD and healthy postmortem eyes using computer-assisted digital analysis of stained tissue examined for increased levels of iron in the retina . To determine whether the iron was chelatable, sections treated with the iron chelator deferoxamine were compared with adjacent, nonchelated sections. Compared to healthy maculas, the maculas affected by AMD had statistically significant increases in the total iron level, some of which was chelatable. Iron was present in the retinal pigment epithelium and Bruch’s membrane in maculas from eyes with drusen only, geographic atrophy and exudative AMD. Iron was present occasionally in relatively healthy areas.

Posted by kjalali at 05:51 PM

August 23, 2003

Correction of laser calibration errors key to visual outcomes :Ablation software can make adjustments in energy to improve visual quality, contrast sensitivity
June 1, 2003 Ophthalmology Times

Adjustment for energy delivery calibration errors represents the single most important step excimer laser manufacturers can take toward achieving improved visual outcomes in eyes undergoing corneal ablative refractive surgery, said Jack T. Holladay, For existing lasers, delivered fluence for a given ablation profile is based on laser calibration using a flat plane on plastic. However, because the cornea is a curved surface and the laser beam strikes it at an oblique incidence rather than perpendicularly, there is fluence degradation at every point except the very center, explained Dr. Holladay, Consequently, the amount of tissue removed is less than expected, and the magnitude of that loss increases progressively as the treatment moves farther peripherally onto a steeper surface. At 2 mm from the center, the laser removes approximately 84% of the intended amount of tissue. At 4 mm, that number drops to about 72%, based on comparing desired tissue removal to actual tissue removal using height data.

Posted by mmiraftab at 01:01 PM

August 22, 2003

Spontaneous retinal venous pulsation: aetiology and significance
J Neurol Neurosurg Psychiatry 2003;74:7–9
Spontaneous retinal venous pulsation is seen as a subtle variation in the calibre of the retinal vein(s) as they cross the optic disc. The physical principles behind the venous pulsations has been the point of much debate. Initial theories suggested that the pulsation occurred because of the rise in intraocular pressure in the eye with the pulse pressure. This article presents an argument that this is not the case. The pulsations are in fact caused by variation in the pressure gradient along the retinal vein as it traverses the lamina cribrosa. The pressure gradient varies because of the difference in the pulse pressure between the intraocular space and the cerebrospinal fluid. The importance of this is that as the intracranial pressure rises the intracranial pulse pressure rises to equal the intraocular pulse pressure and the spontaneous venous pulsations cease. Thus it is shown that cessation of the spontaneous venous pulsation is a sensitive marker of raised intracranial pressure. The article discusses the specificity of the absence of spontaneous venous pulsation and describes how the patient should be examined to best elicit this important sign.

Posted by mmiraftab at 07:16 PM

The neural basis of Charles Bonnet hallucinations:a hypothesis
J Neurol Neurosurg Psychiatry 2002;73:535–541
Objectives: To describe the hallucinations occurring as a result of a macular hole in each eye and to investigate the neural basis.
Methods: Psychophysical observations including sketches of the hallucinations calibrated for size.Results: All the hallucinations were of the geometric (patterned) type and lasted for only a few days. Conclusions: The observations can be explained on the basis of a “deafferentation” model, which isdescribed in some detail. It is proposed that the hallucinations result from activation of the “blobs” of area V1 and the “stripes” of area V2 in the visual cortex. A theory is proposed to account for the disappearance of the hallucinations by a “filling in” mechanism.

Posted by mmiraftab at 07:02 PM

August 21, 2003

Late and very late initial probing for congenital nasolacrimal duct obstruction: what is the cause of failure?
BJO,Sep,2003

In a prospective interventional case series study, 169 eyes of 125 consecutive patients (1–5 years old) with CNLDO underwent probing under general anaesthesia. Cure was defined as absence of tearing and discharge in the affected eye.
The cure rate was 89% in patients 13–24 months of age and 72% after the age of 24 months (p = 0.01). It was 90.2% in the membranous and 33.3% in the complex CNLDO in both late and very late probing (p<0.0001). There was a high correlation (r = 0.97) and no significant difference between the cure rate at 1 week and final follow up.

Posted by afarahi at 07:45 PM

Intrastromal lamellar femtosecond laser keratoplasty with superficial flap
BJO Sep 2003
Lamellar keratoplasty has usually been performed taking a trephine to delineate the extent of the tissue to be excised, and a knife or similar instrument to remove the lamellar corneal tissue from the underlying deep corneal bed. In a similar way, the lamellar donor tissue was prepared and inserted into the recipient bed. The depth of the lamellar excision extended from the corneal epithelial surface to the deep corneal stroma. Marked disadvantages of the technique have been pronounced corneal astigmatism and optical insufficiencies of the interface between the lamellar graft and the recipient corneal bed caused by irregularities of both surfaces. The purpose of the present report was to describe the new femtosecond laser technology,1–3 which may enable us to perform a new type of intrastromal lamellar keratoplasty with preservation of an intact Bowman’s layer and regular corneal epithelium

Posted by mmiraftab at 05:58 PM

OCT offers early insight into risk of visual-field deterioration
Ophthalmology TimesAugust 1, 2003

San Francisco-Patients with a retinal nerve fiber layer (RNFL) thickness of 80 µm or less are at high risk for developing future visual-field deterioration,Researchers calculated the relative risk that patients would have for visual-field deterioration in the follow-up period. They found three independent baseline characteristics:
Initial clinical diagnosis of glaucoma.
Black race.
OCT mean nerve fiber layer <80 µm.
Additionally, they found that being male and under age 60 was protective with reference to future visual-field progression.
"If a patient's RNFL is in the vicinity of 80 µm-even if his or her visual field is currently normal or has been stable-he or she is at high risk for developing future visual-field deterioration,"

Posted by mehdi khanlari at 05:55 PM

Retinectomy for treatment of intractable glaucoma: long term results
BJO Sep 2003
This was a consecutive interventional case series. In 44 consecutive eyes (39 patients, 22 men and 17 women) retinectomy was performed to lower the intraocular pressure (IOP) in patients with uncontrolled IOP (>35 mm Hg for more than 4 months) despite conventional filtering surgery and drug treatment. Pars plana vitrectomy was performed and the peripheral retina was surgically excised to various degrees. The procedure was concluded by an intraocular gas tamponade of 20% C3F8. Included were patients with neovascular glaucoma (12 eyes), infantile and juvenile glaucoma (three eyes), secondary glaucoma due to aphakia (13 eyes), severe ocular trauma (seven eyes), uveitis (seven eyes), and glaucoma in Ehlers-Danlos syndrome (two). All patients underwent successful surgical retinectomy. All patients were followed for 5 years. Mean postoperative IOP after 4 years was 15.7 (SD 9.4) mm Hg, representing a decrease of IOP by 61% compared to the preoperative level (41.2 (9.4) mm Hg). In 52.3% of eyes long term regulation of IOP could be achieved without complications. Retinectomy was least effective in neovascular glaucoma because of central retinal vein occlusion (CRVO). Eyes with glaucoma secondary to uveitis showed a tendency towards low IOP levels with subsequent phthisis bulbi. The initial visual acuity of all patients was lower than 20/50 (mean 1.8 (0.8) logMAR) in the treated eye. Final visual acuity was 2.3 (0.6) logMAR. 21 out of 44 cases developed retinal complications (retinal detachment or proliferative vitreoretinopathy (PVR)) after surgery, requiring silicone tamponade in 11 eyes (52%) either for persistent low IOP or for PVR. Nine eyes developed phthisis, seven of which were enucleated during the follow up. Long term results after retinectomy demonstrate its efficacy in otherwise intractable glaucoma. Efficacy and safety of retinectomy are dependent on the underlying disease.

Posted by mmiraftab at 05:43 PM

Software innovation optimizes functional vision for myopics
Platform minimizes LASIK-induced spherical aberration, maximizes the effective optical zone
Ophthalmology Times July 15, 2003

San Francisco-Early LASIKdata for myopic astigmatism using Nidek's NAVEX platform, incorporating the OATz (Optimized Asphe-rical Transition Zone) ablation algorithm, results in exceptional treatment accuracy and quantitative and qualitative vision out-comes, said Arturo Chayet, MD, at the meet-ing of the American Society of Cataract and Refractive Surgery. OATz is a software innovation by Paola Vinciguerra, MD, to reduce postoperative night vision complaints by minimizing LASIK-induced spherical aberration and maximizing the effective optical zone. It achieves an increase in the effective optical zone by creating a more flawless blending of the optical zone and transition zone, while simultaneously eliminating any abrupt power change between the transition zone and untreated peripheral cornea. On topography, the effect of OATz treatment is seen as an enlarged blue zone with reduced color intensity and peripheral displacement of the "red ring." The red ring is a marker of a large corneal power dioptric gradient that results after conventional excimer laser ablation and that can cause spherical aberration and adverse visual phenomenon if it lies within the pupil diameter.

Posted by mehdi khanlari at 05:32 PM

Bilateral diffuse lamellar keratitis following bilateral simultaneous versus sequential laser in situ keratomileusis
BJO September 2003
Aim: To determine the difference in the incidence of bilateral diffuse lamellar keratitis (DLK) in patients undergoing simultaneous versus sequential laser in situ keratomileusis (LASIK) as an indication of intrinsic risk for inflammation. A retrospective non-comparative case series of 1632 eyes that had undergone bilateral, simultaneous or sequential LASIK between April 1998 and February 2001 at a university based refractive centre by three surgeons. All cases that developed clinically evident DLK were identified and reviewed. In order to identify isolated cases and exclude those caused by environmental factors, when more than one patient in a given session developed DLK, the session was excluded. The main outcome measure was the incidence of unilateral and bilateral isolated, non-epidemic DLK. Of 1632 eyes, 126 eyes (7.7%) of 107 patients developed at least grade 1 DLK. In six operating sessions, DLK was observed in more than one patient per session, and on this basis 13 patients were excluded. 16 of the 94 remaining patients developed DLK in both eyes (17.0%). Six of 41 patients (14.6%) in the simultaneous group, versus 10 of 53 patients (18.9%) in the sequential group developed bilateral DLK (p >0.5). In isolated, non-epidemic bilateral DLK, a similar incidence was observed regardless of whether the surgery was simultaneous or sequential, suggesting an underlying intrinsic cause for DLK.

Posted by mmiraftab at 05:28 PM

A dual optic accommodating foldable intraocular lens
BJO September 2003
dual.bmp
Ray tracing analysis suggested that anterior movement of the anterior optic of a dual optic IOL design with a high power anterior converging lens and a compensatory posterior diverging lens produces significantly greater change in object distance compared similar displacement of single optic IOL. For example, as described earlier, based on the assumptions listed in Table 1, a 1 mm anterior axial movement of a single optic 19 D IOL would produce a change in conjugation power of the eye of approximately 1.2 D. However, for a dual optic system placed in the same model eye, assuming an anterior + 32 D lens separated by 0.5 mm from a posterior -12 D lens, 1 mm forward displacement of the anterior convex lens is calculated to produce a change in conjugation power of approximately 2.2 D.

This model was used in the fabrication of prototype lenses (Fig 2) The lens as shown is a single piece design constructed of silicone in order to facilitate folding. Five mm diameter optics are connected by haptics with spring function. The device has length 9.5 mm and width 9.8 mm. When compressed, the total lens thickness is 2.2 mm. Based on the optical calculations described above, it is evident that a greater change in conjugation power per unit axial displacement can be generated by choosing a more powerful anterior lens, but the advantages of increased accommodative range must be weighed against the increased optical sensitivity of the system. Thus, at present our power choice for the anterior lens is within a range of 30 D and 35 D, and the posterior lens assigned a variable diverging power as required to produce emmetropia for a given eye. The optics are connected by arms, the length and thickness of which can be varied to produce a range of response to capsular bag tension

Posted by mmiraftab at 05:23 PM

Epithelial iris cyst treatment with intracystic ethanol irrigation
Zohreh Behrouzi, MD1* and Aliasghar Khodadoust, MD2
1 Department of Ophthalmology, Emam Hossein Hospital, Shahid Beheshti University School of Medicine, Tehran, Iran
2 Department of Ophthalmology, Yale University School of Medicine, New Haven, Connecticut

Ophthamology, Aug, 2003
CONCLUSION: Ethanol irrigation is a cost-effective and safe procedure, and we recommend consideration of the procedure for treatment of iris epithelial cysts.

Posted by pakravanmd at 09:18 AM

Retinopathy in patients with diabetic ophthalmoplegia
Ophthalmology, Aug, 2003

Diabetic ophthalmoplegia most commonly involves CN 3 and 6, with relative sparing of CN 4. Multiple cranial nerves are affected simultaneously in 2.6% of cases, and consecutive palsies occurred in 3.9% of cases. Type II diabetics with ocular motor CN palsy have significantly less diabetic retinopathy than do controls. This may imply a different pathophysiologic mechanism for these two microvascular complications of DM.
A final conceivable explanation for our findings is that ocular motor CN paresis imparts a protective effect against retinopathy (or is a marker for some protective effect) via an as yet undiscovered process at the genetic or cellular level.

Posted by pakravanmd at 09:05 AM

Lacquer crack formation after LASIK
Ophthalmology, Aug, 2003

Reasons for the development of lacquer cracks remain unclear. They may be the healed mechanical breaks of retinal pigment epithelium (RPE), Bruch's membrane, and choriocapillaris complex and have been related to a weak Bruch's membrane. It is believed that lacquer cracks as well as other macular degenerative changes in pathologic myopia are caused by mechanical stretching of the retina and choroid within the posterior staphyloma.
Different hypotheses have tried to explain the posterior segment pathology after LASIK, such as mechanical stress caused by the intraocular pressure (IOP) elevation produced by the pneumatic suction ring, which may induce tangential stress at the posterior segment and even cause a rupture in Bruch's membrane. Another cause of stress might be the impact of excimer laser energy on the cornea producing stress waves along the axis of the eye. Stress wave amplitudes during photoablation reach a maximal pressure focus of up to 100 atmospheres located in the posterior lens and anterior vitreous and then decrease to <10 atmospheres at the retina.
Lacquer cracks often lead to poor visual outcomes because of choroidal neovascularization and macular atrophy in pathologic myopia. The risk of developing lacquer cracks in highly myopic patients corrected by LASIK, though uncommon, must be kept in mind. This is true especially in highly myopic patients with myopic retinopathy in whom LASIK could be used to correct residual defects after posterior chamber or phakic intraocular lens implantation.

Posted by pakravanmd at 08:32 AM

August 17, 2003

Glucose-sensing device emdedded in an especial contact lens
Eyeworld August 2003


Seventeen million Americans that struggle with diabetes must draw blood every day to check their blood sugar levels. But a new innovation may change the way patients monitor their disease.The device, now under development, is a chemical sensor that changes color in response to glucose concentrations in tears. If proven effective, it may someday be embedded in contact lenses, allowing users to monitor levels by looking in a mirror.Researchers envision that the sensor will be used in contact lenses or as an ocular insert worn inside the eyelid. “The diabetic patient would look at the color using a mirror and compare it to a wheel of color around the mirror,” . The sensor will be green if concentrations are normal, red at low levels, and blue at high levels.When you measure blood or urine, you’re measuring at a spot in time,” Foulks said. “And you have to obtain a specimen at that particular point in time, whereas this would be a continuous monitor.”

Posted by mehdi khanlari at 11:05 PM

AlphaCor
Eyeworld August 2003

The first U.S. surgeries with AlphaCor were performed in mid-May by R. Doyle Stuling, M.D., Ph.D., professor of ophthalmology, Emory University, Atlanta, and Edward Holland, M.D., professor of clinical ophthalmology, University of Cincinnati, and director, cornea service at the Cincinnati Eye Institute, Ohio. Since then, surgeries have been performed by James Aquavella, M.D., Department of Ophthalmology, University of Rochester Medical Center, Rochester, N.Y., Anthony Aldave, M.D., Jules Stein Eye Institute, University of California at Los Angeles, and Richard Eiferman M.D., clinical professor of ophthalmology, University of Louisville, Ky.
• To date, a total of 12 cases have been performed in the U.S. with several other surgeries scheduled;
• At press time, 70 such surgeries were performed worldwide;
• The probability of retention at one year is 80%;

Posted by mehdi khanlari at 10:53 PM

AlphaCor
Eyeworld August 2003


The surgical steps are as follows:
1) The first step to a successful AlphaCor transplant is to create a Gunderson flap, a very thin flap of conjunctiva fashioned from the globe above the cornea. The purpose of this conjunctival flap is to stabilize the cornea so that it will heal and survive over the implant. After the flap is created, it is moved below the cornea so that the AlphaCor implantation can be completed.
2) Next, an incision is made at the superior limbus to create a lamellar dissection that extends to the inferior limbus.
3) A 3-mm hole is then trephined through the center of the posterior corneal lamella.
4) The keratoprosthesis is then placed in the lamellar pocket and centered on the posterior opening. Sutures may be placed through the cornea to anchor the AlphaCor in position.

Posted by mehdi khanlari at 10:49 PM

August 16, 2003

B&L Licenses New IOL Technology
CRST August2003

On July 21, Bausch & Lomb (Rochester, NY) announced it had entered into a licensing agreement with Faezeh Mona Sarfarazi, MD, for the development, marketing, and production of a proprietary IOL technology she invented. The IOL is a single-piece, molded silicone lens with a dual-optic design, which Bausch & Lomb believes has the potential to provide presbyopic patients with good distance vision and the ability to read without reading glasses. The company will fund research and development of the technology and make milestone-based payments to Dr. Sarfarazi, as well as pay royalties upon successful commercialization.

Posted by mehdi khanlari at 11:15 PM

Simultaneous Bilateral Cataract Surgery
CRST August 2003


Simultaneous bilateral cataract surgery does not seem to be associated with a greater risk of complications than uneventful unilateral cataract surgery, provided the surgical staff takes the proper precautions to reduce risks unique to the bilateral procedure. These safety measures include assuring that all solutions, medications, and instruments are selected from different lots in order to reduce the potential for bilateral infections. In addition, almost any serious preoperative ophthalmic disorder—including blepharitis, glaucoma, lenticular subluxation, unusually dense or expected difficult cataract, and significant diabetic retinopathy or other retinal pathology—should precipitate a careful evaluation of the patient’s particular status and any potential additional risks prior to bilateral surgery. Any significant intraoperative complication with the first eye is a signal that the surgeon should defer operating on the second eye. Bilateral cataract surgery is not an appropriate choice for all surgeons. It is best suited for confident, experienced surgeons who are aware of their complication rates and biometric accuracy.

Posted by mehdi khanlari at 10:50 PM

Brewer Science offers High Refractive Index Polymer Coatings
OPTICS.ORG News from Week 33 2003
OptiNDEX™ developmental coatings have the following attributes:

* Refractive index up to 1.90

* Highly Transparent (500-1700 nm)

* Excellent optical clarity, film quality and durability

* Excellent storage stability

Posted by mmiraftab at 01:00 PM

August 15, 2003

A comparison of atropine and patching treatments for moderate amblyopia by patient age, cause of amblyopia, depth of amblyopia, and other factors
The Pediatric Eye Disease Investigator Group
Ophthalmology (2003) 110: 1632-1637
RESULTS: Improvement in the amblyopic eye visual acuity was slightly greater in the patching group compared with the atropine group in all subgroups based on patient characteristics. The relative treatment effect did not vary with age (P = 0.84), cause of amblyopia (P = 0.68), or baseline amblyopic eye acuity (P = 0.59). Patients with acuity of 20/80 to 20/100 who were prescribed 10 or more hours a day of patching showed a more rapid improvement in acuity than did patients prescribed a lesser amount of patching (P = 0.01) or than did patients in the atropine group (P < 0.001), but by 6 months, the differences were not significant (P = 0.47 and 0.15, respectively).

CONCLUSIONS: A beneficial effect of both patching and atropine is present throughout the age range of 3 to younger than 7 years old and the acuity range of 20/40 to 20/100. Patients with acuity of 20/80 to 20/100 improve faster when a greater number of hours of patching is prescribed, but by 6 months, the amount of improvement is not related to the number of hours of patching initially prescribed.

Posted by mmiraftab at 05:38 PM

Topical cyclosporine A 0.5% as a possible new treatment for superior limbic keratoconjunctivitis
Ophthalmology (2003) 110: 1578-1581
PURPOSE: To report the early success of the use of topical cyclosporine A 0.5% drops to treat Theodore’s superior limbic keratoconjunctivitis (SLK).
DESIGN: A retrospective noncomparative case series.
PARTICIPANTS: Five patients diagnosed with SLK.
INTERVENTION: All five patients were treated with topical cyclosporine A 0.5% drops as primary or adjunctive therapy after treatment failure in some of prednisolone acetate 1% drops and topical silver nitrate 0.5% application. Topical cyclosporine A 0.5% drops were used four times a day in both eyes.
MAIN OUTCOME MEASURES: Resolution of symptoms (foreign body sensation and irritation) and signs (rose bengal staining, tarsal papillary reaction, and injection).
RESULTS: All five patients had long-term (6 months to 3 years) improvement of irritation and foreign body sensation, as well as improvement of injection and filamentary keratitis. Aside from burning on instillation, there were no complications related to this therapy.
CONCLUSIONS: Topical cyclosporine A 0.5% is helpful as primary or adjunctive therapy for SLK. It may also be used as a maintenance drug to prevent recurrence. Further study may delineate the specific role and treatment parameters for the use of topical cyclosporine A 0.5% in the treatment of SLK

Posted by mmiraftab at 05:26 PM

Accommodative IOL system improves both distance and near visual acuity
Eyeworld August 2003

A dual lens IOL system called the DualFlex IOL system (Stein created the term to describe a double implant technique he performs with two standard STAAR IOLs) facilitates accommodation following clear lensectomies and cataract extractions and has the potential to revolutionize refractive surgery and implant protocols.I started to perform double implants to treat high degrees of hyperopia because of the limits with laser vision correction. What I found is that not only did we correct hyperopia with the double implants but also the patients reported an accommodative effect.The technique involves the insertion of a plate lens approximately two-thirds power in the capsular bag and the insertion of a three-piece silicone lens of one-third power in the sulcus.In my initial study of 24 eyes, the average preoperative spherical equivalent was +8.6 D, with a range of +5 D to +16 D. These patients ranged in age from 40 to 67 years, with a mean age of 53 years Results from the DualFlex study show that the higher the degree of preop hyperopia, the better the near acuity. Additionally, near vision correction has remained stable in all patients that received dual lens implants with an average of 13 months of follow up.The accommodative effect from the DualFlex system appears to be the result of ciliary muscle contraction and increased vitreous pressure pushing the lens in the sulcus forward, with nothing holding the lens back other than the iris. But, one of the questions yet to be answered is whether similar results will be found when both lenses are put in the bag and large capsulorhexis is done read more...

Posted by mehdi khanlari at 12:38 PM

Laser in situ Keratomileusis for Correction of Induced Astigmatism From Cataract Surgery
Journal of Refractive Surgery Vol. 19 No. 4 July/August 2003
Hamid Norouzi, MD; Mohsen Rahmati-Kamel, MD

To evaluate the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) to correct residual astigmatism after cataract surgery LASIK was performed on 20 eyes of 20 patients with refractive myopic or mixed astigmatism (3.00 to 6.00 D) at least 1 year after extracapsular cataract extraction with posterior chamber intraocular lens implantation without complication. Each eye received bitoric LASIK with the Nidek EC-5000 excimer laser and the Automated Corneal Shaper microkeratome At 6 months after LASIK, mean refractive cylinder decreased from 4.64±0.63 D to 0.44±0.24 D (P<.001). Mean percent reduction of astigmatism was 90.4±5.0% (range 80% to 100%). Mean spherical equivalent refraction decreased from -2.19±0.88 D (range -1.00 to -3.88 D) to -0.32±0.34 D (range -1.25 to +0.38 D) (P<.001). Vector analysis showed that the mean amount of axis deviation was 0.7±1.2° (range 0° to 4.3°) and the mean percent correction of preoperative astigmatism was 92.1±5.9% (range 85.6% to 108%). Eighty-five percent of all eyes had a mean spherical equivalent refraction and mean cylinder within ±0.50 D of emmetropia. Change in spherical equivalent refraction and cylinder from 2 weeks to 6 months was .0.50 D in 90% (18 eyes) and 95% (19 eyes), respectively. Spectacle-corrected visual acuity was not reduced in any eye. Diffuse lamellar keratitis occurred in three eyes (15%) after LASIK, and were treated successfully with eyedrops.
CONCLUSIONLASIK was an effective, predictable, stable, and safe procedure for correction of residual myopic or mixed astigmatism ranging from 3.00 to 6.00 D with a low spherical component after cataract surgery

Posted by mehdi khanlari at 12:07 PM

Pupil size and quality of vision after LASIK
Ophthalmology August 2003

Patients with large pupils had more quality of vision symptoms in the early postoperative period, but no correlation was observed 6 months after surgery. Factors related to long-term symptoms include the level of treatment (preoperative myopia), preoperative contrast acuity, postoperative UCVA, and residual cylinder. Most of the variability in visual quality could not be explained by preoperative or clinical outcome measures, including pupil size.

Posted by mehdi khanlari at 11:56 AM

Image Quality in Myopic Eyes Corrected With Laser in situ Keratomileusis and Phakic Intraocular Lens
Journal of Refractive Surgery Vol. 19 No. 4 July/August 2003

To compare image quality due to higher-order aberrations following laser in situ keratomileusis (LASIK) or implantation of phakic intraocular lens (PIOL) to correct high myopia.Postoperative wavefront examinations, normalized to a pupil size of 5.5 mm, were obtained for 19 LASIK and 20 PIOL eyes for the same surgeon over the same time period. Higherorder aberrations and simulated retinal images were compared For this small sample, the LASIK eyes yielded an average three times more spherical aberration and two times more coma than PIOL eyes. The effects of these differences were visualized using the simulated retinal images.CONCLUSION Spherical aberration and coma are the major differences between postoperative LASIK and PIOL higher-order aberrations, and simulated retinal images can be used to visualize these effects.

Posted by mehdi khanlari at 11:53 AM

Optic Disc Traction Syndrome Associated With Central Retinal Vein Occlusion
Arch Ophthalmol. 2003;121:1093-1097.

Optic disc traction was found by OCT in the 3 patients. In each, the disc was elevated, associated with either incomplete posterior vitreous detachment (2 eyes) or vitreopapillary fibrous membrane (1 eye). Secondary peripapillary retinal traction and macular or retinal detachment developed ("optic disc traction syndrome"). These findings were less marked, or not evident, on both clinical examination and ocular ultrasonography.
Conclusions Optic disc traction and secondary localized retinal detachment can develop after ischemic CRVO and may contribute to the poor visual acuity. This syndrome should merit special attention before surgery for CRVO is planned. The use of OCT was helpful to diagnose this syndrome.

Posted by mehdi khanlari at 11:39 AM

August 14, 2003

Surgeons debunk myths of oculoplastic surgery
EyeWorld,August,2003

Oculoplastic surgeons and pediatric ophthalmologists share the same goals concerns, but sometimes different strategies.Read more......

Posted by afarahi at 10:22 AM

Refractive Error and Ethnicity in Children
Archive of Ophthalmology,August,2003

The study population included 2523 children (534 African American, 491 Asian, 463 Hispanic, and 1035 white) in grades 1 to 8 (age, 5-17 years).
Overall, 9.2% of the children were myopic, 12.8% were hyperopic, and 28.4% were astigmatic. There were significant differences in the refractive error prevalences as a function of ethnicity (2, P<.001), even after controlling for age and sex . For myopia, Asians had the highest prevalence (18.5%), followed by Hispanics (13.2%). Whites had the lowest prevalence of myopia (4.4%), which was not significantly different from African Americans (6.6%). For hyperopia, whites had the highest prevalence (19.3%), followed by Hispanics (12.7%). Asians had the lowest prevalence of hyperopia (6.3%) and were not significantly different from African Americans (6.4%). For astigmatism, Asians and Hispanics had the highest prevalences (33.6% and 36.9%, respectively) and did not differ from each other (P = .17). African Americans had the lowest prevalence of astigmatism (20.0%), followed by whites (26.4%).
Conclusion There were significant differences in the prevalence of refractive errors among ethnic groups, even after controlling for age and sex (P<.001).

Posted by afarahi at 10:08 AM

The Utility of 0.5% Apraclonidine in the Diagnosis of Horner Syndrome
Arch Ophthalmol. Aug, 2003;

we propose that 0.5% apraclonidine may be substituted for cocaine in the pharmacologic confirmation of Horner syndrome. For localization of the sympathetic lesion, hydroxyamphetamine is still required. If apraclonidine does not cause anisocoria reversal and there is an important therapeutic need to pharmacologically confirm the diagnosis, further assessment with the classic agents should be conducted.

Posted by pakravanmd at 08:51 AM

Myelination of the Macula Associated With Disabling Photophobia
Arch Ophthalmol. AUG, 2003

A 7-YEAR-OLD Latino boy with infantile esotropia complained of extreme glare.His visual acuity was counting fingers at 1 ft OD, and 20/20 OS. The pupils were normal, with no relative afferent pupillary defect.

Fundus photograph showing massive myelination of the retinal nerve fibers overlying the macula, while sparing the fovea. The optic nerve, vascular arcades, and midperiphery are also affected.

Posted by pakravanmd at 08:39 AM

August 12, 2003

Antigenic Specificity of Immunoprotective Therapeutic Vaccination for Glaucoma
Investigative Ophthalmology and Visual Science. 2003;44:3374-3381

PURPOSE. To investigate the antigenic specificity of the immune neuroprotective mechanism that can protect retinal ganglion cells (RGCs) against death caused by high intraocular pressure (IOP).

METHODS. A unilateral increase in IOP was induced in rats by argon laser photocoagulation of the episcleral veins and limbal plexus. Rats with high IOP were immunized with glatiramer acetate (Cop-1, a synthetic copolymer) or with myelin-derived or uveitogenic peptides. When the steroid drug methylprednisolone was used, it was administered intraperitoneally every other day for 12 days.

RESULTS. Vaccination with myelin-derived peptides that reside in the axons failed to protect RGCs from death caused by high IOP. In contrast, IOP-induced RGC loss was reduced by vaccination with R16, a peptide derived from interphotoreceptor retinoid-binding protein, an immunodominant antigen residing in the eye. The benefit of protection against IOP-induced RGC loss outweighed the cost of the monophasic experimental autoimmune uveitis (EAU) that transiently developed in a susceptible rat strain. Treatment with methylprednisolone alleviated the disease symptoms, but caused further loss of RGCs. Cop-1 vaccination was effective in both EAU-resistant and EAU-susceptible strains.

CONCLUSIONS. To benefit damaged neurons, immune neuroprotection should be directed against immunodominant antigens that reside in the site of damage. In a rat model of high IOP, RGCs can benefit from vaccination with peptides derived from proteins that are immunodominant in the eye but not from myelin-associated proteins. This suggests that the site of primary degeneration in IOP-induced RGC loss is in the eye. Cop-1 vaccination apparently circumvents the site-specificity barrier and provides protection without risk of inducing autoimmune disease

Posted by mmiraftab at 11:52 PM

Efficacy of Daunorubicin Encapsulated in Liposome for the Treatment of Proliferative Vitreoretinopathy


To investigate the efficacy of daunorubicin encapsulated in liposome as a drug delivery system to treat PVR, an experimental PVR model was made in pigmented rabbits by injecting a suspension of conjunctival fibroblasts and platelet-rich plasma into the vitreous cavity. Daunorubicin was encapsulated in newly developed empty liposome by mixing the empty liposome with the drug solution.Compared with the control PVR model, daunorubicin prevented the formation of PVR. Although pathologic changes were observed in the eyes injected with daunorubicin alone, there were no adverse effects observed in the eyes injected with daunorubicin encapsulated in empty liposome.

Posted by kjalali at 09:30 PM

August 11, 2003

High- and Low-Risk Profiles for the Development of Multiple Sclerosis Within 10 Years After Optic Neuritis
Arch Ophthalmol. 2003;121:944-949.

Objective To identify factors associated with a high and low risk of developing multiple sclerosis after an initial episode of optic neuritis.

The 10-year risk of multiple sclerosis was 38% (95% confidence interval, 33%-43%). Patients (160) who had 1 or more typical lesions on the baseline magnetic resonance imaging (MRI) scan of the brain had a 56% risk; those with no lesions (191) had a 22% risk (P<.001, log rank test). Among the patients who had no lesions on MRI, male gender and optic disc swelling were associated with a lower risk of multiple sclerosis, as was the presence of the following atypical features for optic neuritis: no light perception vision; absence of pain; and ophthalmoscopic findings of severe optic disc edema, peripapillary hemorrhages, or retinal exudates.
Conclusions The 10-year risk of multiple sclerosis following an initial episode of acute optic neuritis is significantly higher if there is a single brain MRI lesion; higher numbers of lesions do not appreciably increase that risk. However, even when brain lesions are seen on MRI, more than 40% of the patients will not develop clinical multiple sclerosis after 10 years. In the absence of MRI lesions, certain demographic and clinical features seem to predict a very low likelihood of developing multiple sclerosis. This natural history information is a critical input for estimating a patient's 10-year multiple sclerosis risk and for weighing the benefit of initiating prophylactic treatment at the time of optic neuritis or other initial demyelinating events in the central nervous system.

Posted by mehdi khanlari at 11:25 PM

Microkeratome-assisted lamellar keratoplasty for keratoconus: Stromal sandwichJCRS July 2003

This prospective study comprised 9 eyes of 7 keratoconus patients with contact lens intolerance. The donor cornea was prepared with a microkeratome and punched with a 7.25 mm or 7.50 mm trephine. Following the creation of a standard 9.0 mm corneal flap in the host cornea, the donor stromal button was implanted under this corneal flap like a sandwich. Transepithelial photorefractive keratectomy or laser in situ keratomileusis was performed when the corneal topography and refraction stabilized by the end of the sixth postoperative month. Follow-up ranged from 7 to 22 months. All patients gained 5 or more lines (mean 7.2 lines ± 1.6 [SD]), and no patient lost a line of vision. The mean corneal thickness was 432.7 ± 36.1 ìm preoperatively and 578.1 ± 45.1 ìm after refractive surgery.
Conclusions: The early visual results of this surgical technique are promising and seem to be comparable to those with penetrating keratoplasty.

Posted by mehdi khanlari at 11:14 PM

5-Fluorouracil as Chemoadjuvant for Primary Pterygium Surgery: Preliminary Report
Cornea july 2003

Of 25 consecutive white patients, 28 eyes with primary pterygium underwent pterygium excision with intraoperative application of 5-fluorouracil (25 mg/mL for 3 minutes). The superior and inferior conjunctiva was approximated to cover the scleral bed within 1 mm of the limbus. Recurrence of pterygium was defined as postoperative fibrovascular growth more than 1 mm onto the cornea. Eyes with recurrence less than 2 mm were treated with subconjunctival 5-fluorouracil injections.After a mean follow-up of 14.1 ± 3.9 months (mean ± standard deviation), 7 recurrences (25%) were observed. All recurrences were detected within 12 months. In 4 of 7 recurrences, the fibrovascular growths were less than 2 mm. We, therefore, performed subconjunctival 5-fluorouracil injections. In 3 (75%) of 4 recurrences, the fibrovascular growths became atrophic. No serious complications were observed during and after the surgery. However, superficial punctate keratitis, pain, and hyperemia were detected in all patients in the early postoperative period. As a result, of 28 eyes, 4 (14%) had unacceptable cosmetic results and growing recurrences.
Conclusions. This study suggests that intraoperative applications of 5-fluorouracil is both efficient and safe in the treatment of primary pterygium. Additionally, postoperative subconjunctival 5-fluorouracil injections may prevent the progression of fibrovascular tissue.

Posted by mehdi khanlari at 11:08 PM

Replacing Maximum-Tolerated Medications with Latanoprost Versus Adding Latanoprost to Maximum-Tolerated Medications: A Two-Center Randomized Prospective Trial
Journal of Glaucoma 2003; 12(4):347-353
Purpose:
To compare the replacement of every drug with latanoprost 0.005% once a day in glaucomatous eyes with poorly controlled intraocular pressure upon combination therapy, versus addition of latanoprost to the pre-existing treatment.
Patients and Methods:
Study design: prospective, investigator-masked, two-center, randomized clinical trial lasting 3 months. Eligibility criteria: open-angle glaucoma; IOP ?? 21 mm Hg upon the combination of a non-selective beta-blocker with pilocarpine or dorzolamide or both; no previous bulbar surgery; and prior glaucoma therapy lasting at least 2 years. Two treatment arms: (1) addition of latanoprost 0.005% QD to the pre-existing therapy [group A]; (2) substitution with latanoprost alone [group B].
Results:
One hundred thirty-six eyes (68 eyes/treatment group) were randomized according to intraocular pressure level and the number of adjunctive medications to beta blocker. Both treatments provided a significant IOP decrease over baseline (from 23.5 ?? 1.4 to 19.7 ?? 1.9 mm Hg in group A, (P < 0.001); from 23.2 ?? 1.3 to 20.1 ?? 2.2 mm Hg in group B (P < 0.001), paired Student t test). At the end of the follow-up period, group A showed a higher number of intraocular readings less than or equal to 18 mm Hg than group B (42.6% vs. 30.8%; Fisher exact test: P = 0.018).
Conclusions:
In eyes showing an intraocular pressure greater than 21 mm Hg upon combination therapy, the substitution of the pre-existing treatment with latanoprost can provide a significant IOP decrease. However, adding latanoprost to the pre-existing therapy is more likely to achieve a target intraocular pressure less than or equal to 18 mm Hg.

Posted by mmiraftab at 01:20 AM

Visual hallucinations possible side effect of PDT
OSN Auguest 2003
Visual hallucinations may be a side effect of photodynamic therapy for choroidal neovascularization, according to a small study. The phenomenon, occurring immediately after the treatment, has been so far unrecognized, the study authors said.

Posted by mmiraftab at 01:03 AM

August 10, 2003

Minus-power IOL implantation in highly myopic eyes is safe and effective
Eyeworld August 2003

Minus-power IOL implantation in highly myopic eyes is safe and effective. Patients achieved marked improvements in median best-corrected visual acuity (BCVA) and mean spherical equivalent (SE) refraction The powers of the implanted IOLs ranged from -1 D to -6 D. The mean differences between predicted and achieved postoperative SE refraction were +1.09 ± 0.91 D for the SRK/T, +1.13 ± 1.02 D for the Holladay, and +1.53 ± 0.98 D for the Hoffer Q. The study found that all three formulas underestimated the amount of correction by at least 1 D, and the SRK/T equation appeared to be the most accurate and predictable. However, this finding was not statistically significant.Although, on average, all three IOL power formulas underestimated the amount of correction by at least 1 D, these findings varied on an individual basis so that some predictions fell within 1 D of the outcome. “To maintain myopia postcataract surgery in highly myopic eyes, the surgeon must aim for at least 1 D of myopia no matter what equation is used,” he said.None of these patients experienced intraoperative complications. The most common postoperative complications were posterior capsule opacification in 11 of 16 eyes, hyperopia in eight eyes, and capsule wrinkling in two eyes

Posted by mehdi khanlari at 11:43 PM

Hyperthermia technique helps iron out flap striae
Eyeworld August 2003
Eric D. Donnenfeld, M.D., F.A.C.S.

Low-level hyperthermic treatment of longstanding striae in post-LASIK corneal flaps has shown promising results to date. The method appears to work because low heat produces flaccidity and stretching of collagen fibrils without adversely affecting corneal tissue. When collagen is relaxed, stromal lamallae are more malleable. This allows the collagen to return to a more normal configuration.Preoperatively, we applied two drops of topical proparacaine 0.5% two times at five-minute intervals. We used tying forceps to elevate the flap at the slit lamp before placing the patient under an operating microscope. A microwave was used to boil sterile water in a sterile container for five minutes. The water then was allowed to cool at room temperature, while being measured by a sterile thermometer.Meanwhile, an epithelial debridement spatula was used to remove the corneal epithelium and expose the corneal surface, which was irrigated with balanced salt solution. A cyclodialysis spatula elevated the flap, which was reflected backward. After the sterile water cooled to 65 degrees Centigrade, the striae removal spatula was placed inside and heated for 30 seconds.
We then used the two-pronged removal forceps to elevate the flap and keep it under tension. We massaged the flap vigorously with the spatula, which was returned to the warm water every 30 seconds for reheating. Massaging continued for five to 10 minutes, until the striae were visibly decreased. The flap then was laid down, followed by irrigation of the undersurface with BSS using a standard 25-gauge cannula.Past concerns have been expressed about endothelium damage associated with thermal treatment of the cornea. It is true that heating at very high temperatures (more than 75 degrees Centigrade) can cause collagen fibers to gelatinize, resulting in complete disorganization. But the cornea must be heated to at least 60 degrees Centigrade to produce biomechanical changes in corneal tissues.

Posted by mehdi khanlari at 11:31 PM

Conductive Keratoplasty to Correct Hyperopic Astigmatism
JOURNAL OF REFRACTIVE SURGERY Vol. 19 No. 4 July/August 2003

To evaluate the efficacy of conductive keratoplasty in the treatment of pre-existing and surgically induced hyperopic astigmatism.In this prospective, noncomparative case series, four eyes of four subjects, two female and two male (age 25 to 47 yr) were treated for hyperopia (up to +5.50 D) and hyperopic astigmatism (up to +5.75 D) with the Refractec ViewPoint conductive keratoplasty system. The follow-up period was 6 months. Uncorrected and spectaclecorrected visual acuity, manifest and cycloplegic refraction, and videokeratographs were obtained before and after surgery. We treated two patients who had already had LASIK, one of them with a decentered ablation and the other with flap striae, one patient after PRK, and one patient with keratoconus RESULTS:No complications were observed. No eye lost lines of spectacle-corrected visual acuity. All eyes showed improvement of uncorrected visual acuity of 3 or more lines. Videokeratographs demonstrated improved centration and reduction in keratometric power readings. Each eye was analyzed separately, including a comparative analysis of the proposed nomograms and quality of vision after surgery.
CONCLUSIONS:Conductive keratoplasty may be a minimally invasive solution for patients with irregular hyperopic astigmatism, offering improved quality of vision in instances of flap striae by tightening the central cornea

EMKH

Posted by alireza habibollahi at 03:57 PM

August 09, 2003

Intraocular lens calculations in patients with corneal scarring and irregular astigmatism
JCRS July 2003


Two patients with irregular corneal astigmatism had an IOL exchange after a “surprise” post-cataract-surgery refraction. In the first case, the patient had a post-cataract-surgery refraction of +5.50 –0.75 × 69 and in the second case, a refraction of –7.00 –1.00 × 180. The central corneal power before IOL exchange was assessed using manual keratometry, various computerized videokeratography curvature and power maps, and contact lens overrefraction. The total axial power map (Orbscan®, Bausch & Lomb), total optical power map (Orbscan), and contact lens overrefraction method provided the most accurate estimates of central corneal power in these 2 patients.
Conclusion:
Computerized scanning-slit videokeratography, which analyzes the anterior and posterior surfaces of the cornea, and the contact lens overrefraction method gave good estimations of corneal power in patients with irregular corneal astigmatism. This type of analysis may improve the accuracy of IOL calculation in patients with corneal pathology and irregular astigmatism.

Posted by mehdi khanlari at 11:40 PM

Laser cataract surgery: Technique and clinical results
JCRS July 2003

With ultrasound cataract surgery, there were no significant changes in IOP compared with the preoperative measurements. Laser treatment of 3+ and 4+ cataracts resulted in IOP increases of 12.6% and 18.2%, respectively, compared with 1+ and 2+ cataracts (P <.001). Slight endothelial cell losses occurred in all cases. With ultrasound, the mean decrease was 2.8%, and with laser surgery, the results were similar except for a significant decrease of 13.4% with 4+ cataracts. There was a correlation between pachymetry and surgical time when the trauma related to surgical time and hydrodynamic flow in the anterior chamber was assessed. With ultrasound, the visual acuity was similar with all types of cataract; with the laser, similar normal values were seen with 1+ and 2+ cataracts but decreased values were seen with 3+ cataracts and lower values with 4+ cataracts—0.43 compared to 0.84 best corrected visual acuity with same-density cataracts treated with ultrasound (P <.0005). Patients with 4+ cataracts treated with the laser developed more complications than those treated with ultrasound.
Conclusions:
The Er:YAG laser was as effective and reliable as ultrasound in removing soft and medium-density cataracts. With dense cataracts, the surgical length produced more trauma and complications during laser treatment than during ultrasound treatment.

Posted by mehdi khanlari at 11:35 PM

Superficial keratectomy with mitomycin-C for the treatment of salzmann’s nodules
JCRS July 2003

This retrospective consecutive case series comprised 30 eyes of 25 patients who had superficial keratectomy with MMC between January 1997 and June 2000 at a large tertiary-care center. Twenty-four patients reported improvement in their symptoms. The remaining patient lost 1 line of visual acuity. Ninety-seven percent of eyes maintained or improved best corrected visual acuity. No patient had a recurrence of Salzmann’s nodular degeneration over a mean follow-up of 28 months ± 15 (SD) (range 4.0 days to 4.1 years).
Conclusions:
Superficial keratectomy with MMC appears to be a valid and safe method for treating and preventing the recurrence of Salzmann’s nodular degeneration.

Posted by mehdi khanlari at 11:29 PM

Simultaneous bilateral cataract surgery
JCRS July 2003

This retrospective study reviewed the results of 1020 consecutive patients (2040 eyes) who had SBCS by endolenticular phacoemulsification through a clear corneal incision on the corneal steep axis with foldable posterior chamber intraocular lens implantation. The surgeries were performed by the same surgeon from January 1996 to January 2002 as 2 consecutive independent procedures under topical and intracameral anesthesia. Outcome measures included intraoperative and postoperative complications, postoperative uncorrected and best spectacle-corrected visual acuities, refractive error, and patient satisfaction.
Conclusions:
Simultaneous bilateral cataract surgery did not lead to an increased incidence of intraoperative or postoperative complications. The visual acuity results were good, and the patients were pleased. No complications were observed that could be attributed to the procedures being done bilaterally.

Posted by mehdi khanlari at 11:24 PM

August 08, 2003

Effect of a tight necktie on intraocular pressure
BJO,August,2003

40 eyes of 20 normal subjects and 20 open angle glaucoma patients (all male) were enrolled. IOP was measured with an open shirt collar, 3 minutes after placing a tight necktie, and 3 minutes after loosening it. All measurements were made by the same examiner.
Mean IOP in normal subjects increased by 2.6 (SD 3.9) mm Hg and in glaucoma patients by 1.0 (1.8) mm Hg . In normal subjects, IOP in 12 eyes was increased by 2 mm Hg and in seven eyes by 4 mm Hg. In glaucoma patients, IOP in six eyes was increased by 2 mm Hg and in two eyes by 4 mm Hg.
Conclusion: A tight necktie increases IOP in both normal subjects and glaucoma patients and could affect the diagnosis and management of glaucoma.

Posted by afarahi at 07:22 PM

August 07, 2003

Injection sites of botox, for treatment of migraine headache;
practical Neurology, July, 2003



EMKH

Posted by pakravanmd at 03:26 AM

August 06, 2003

Light Scatter Causes the Grayness of Detached Retinas
Arch Ophthalmol. 2003;121:1002-1008
Objective To investigate the cause of the gray appearance of the detached retina
Results Calculations predicted a gaussian distribution of laser light scattering with increased diffusion with increasing distance from the medium to the target. The image clarity, , increased rapidly in the first 50 µm of separation of the retina and tape from the test target and the rate of increase diminished thereafter. Removal of the outer retina with an excimer laser improved retinal transparency.

Conclusions Data explain that the gray appearance of the detached retina results from light scattering. This phenomenon likely results, at least in part, because of the irregular outer retinal surface at the level of the photoreceptors.

Clinical Relevance The findings suggest that visual loss in retinal detachment may result, in part, from optical properties of the detached retina and have implications for visual recovery and subretinal surgery.

Posted by mriazi at 10:27 PM

Plume evacuator may lessen health risk for LASIK and PRK
OCULAR SURGERY NEWS 7/15/03
A high-filtration mask and high turnover-time ventilation system may also reduce the risk of surgical smoke. Further study is needed.
It is unclear whether inhaling surgical smoke when performing LASIK and photorefractive keratectomy procedures poses a health threat. But some physicians feel it may be better to be safe than sorry. “We cannot say at this time that there is a health hazard, but there is a theoretical health hazard,” said Howard V. Gimbel, MD, FRCSC, medical director of the Gimbel Eye Centre in Calgary, Canada, and professor and chair of the department of ophthalmology of Loma Linda University. There are also some anecdotal reports of people who think they may have developed a respiratory problem from the plume. Anything you inhale can be an irritant. Some people are even bothered by perfume. If we can smell something, it means it is getting to our nostrils and into our lungs. However, nothing has been proven yet,”I believe that LASIK and PRK surgeons who use the excimer laser need to pay more attention to the plume particles. The size of these particles and the size distribution are important,

Posted by mmiraftab at 12:29 AM

August 05, 2003

Optociliary Venous Anastomosis After Radial Optic Neurotomy for Central Retinal Vein Occlusion
OSN august 2003

Radial optic neurotomy has been shown to be beneficial for the treatment of central retinal vein occlusion. Some patients developed optociliary venous anastomosis after radial optic neurotomy for central retinal vein occlusion with improvement in vision and clinical appearance. Optociliary venous anastomosis may portend a favorable prognosis.

Posted by kjalali at 09:51 PM

August 04, 2003

Case-control study of endophthalmitis after cataract surgery comparing scleral tunnel and clear corneal wounds*
AJO, Aug, 2003

In this retrospective, case-controlled study, clear corneal incisions were found to be a statistically significant ( threefold greater risk of endophthalmitis) risk factor for acute postcataract surgery endophthalmitis when compared with scleral tunnel incisions.

Posted by pakravanmd at 07:24 AM

Randomized clinical trial of topical betaxolol for persistent macular edema after vitrectomy and epiretinal membrane removal
AJO, August, 2003

Topical betaxolol appeared to have a favorable treatment effect in eyes with macular edema that remained after vitrectomy and removal of epiretinal membrane.

Posted by pakravanmd at 07:15 AM

August 02, 2003

The Tehran Eye Study: research design and eye examination protocol
Hassan Hashemi1, 2 , Akbar Fotouhi3, 2 and Kazem Mohammad3
1Farabi Eye Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
2Noor Vision Correction Center, Tehran, Iran
3Epidemiology and Biostatistics Department, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran

BMC Ophthalmology ,July,2003

Background
Visual impairment has a profound impact on society. The majority of visually impaired people live in developing countries, and since most disorders leading to visual impairment are preventable or curable, their control is a priority in these countries. Considering the complicated epidemiology of visual impairment and the wide variety of factors involved, region specific intervention strategies are required for every community. Therefore, providing appropriate data is one of the first steps in these communities, as it is in Iran. The objectives of this study are to describe the prevalence and causes of visual impairment in the population of Tehran city; the prevalence of refractive errors, lens opacity, ocular hypertension, and color blindness in this population, and also the familial aggregation of refractive errors, lens opacity, ocular hypertension, and color blindness within the study sample.
Methods Design
Through a population-based, cross-sectional study, a total of 5300 Tehran citizens will be selected from 160 clusters using a stratified cluster random sampling strategy. The eligible people will be enumerated through a door-to-door household survey in the selected clusters and will be invited. All participants will be transferred to a clinic for measurements of uncorrected, best corrected and presenting visual acuity; manifest, subjective and cycloplegic refraction; color vision test; Goldmann applanation tonometry; examination of the external eye, anterior segment, media, and fundus; and an interview about demographic characteristics and history of eye diseases, eye trauma, diabetes mellitus, high blood pressure, and ophthalmologic cares. The study design and eye examination protocol are described.
Conclusion
We expect that findings from the TES will show the status of visual problems and their causes in the community. This study can highlight the people who should be targeted by visual impairment prevention programs.

Posted by afarahi at 06:18 PM

Comparison of Cosmetic Results in Frontalis Sling Operations: The Eyelid Crease Incision Versus the Supralash Stab Incision
Journal of Pediatric Ophthalmology and Strabismus , July/August, 2003

In addition to ptosis, the lack of eyelid crease is one of the main cosmetic problems of patients with poor levator function.
Results of this study indicated that the eyelid crease approach provided better functional and cosmetic results than did the supralash stab incision in frontalis sling operations. The passage of the sling material behind the orbital septum by direct visualization in the eyelid crease approach is one of the main factors affecting the surgical success of the frontalis sling operation.

Posted by afarahi at 10:53 AM

IOL implantation promising for pediatric traumatic cataract
A study finds good visual recovery, yet PCO is still a factor.
OSN,8/1/2003

Trauma is a leading cause of unilateral blindness in children.Replacing a pediatric traumatic cataract with an IOL will likely result in favorable visual outcomes in the absence of central corneal or macular scarring, according to one surgeon.
At the American Society of Cataract and Refractive Surgery meeting, Dr. Wilson presented a review of 40 consecutive cases he operated on for traumatic cataracts. The age at surgery ranged from 1.4 to 13.9 years.
Cataract surgery was performed an average of 6 weeks after initial repairs (1 day to 84 months).
The median preoperative best corrected visual acuity was hand movements. Preop complications in the group were very common (lens rupture in 19 patients, marked hyphema in 12, corneal scars in or near the visual axis in 11, iris sphincter damage in nine, iridodialysis in eight, significant zonular loss in five, vitreous hemorrhage in four, retinal detachment in three).
Most patients received IOLs in the capsular bag.
Postop complications were:Pupillary capture ( an IOL-related complication) in four patients, macular scarring in four patients and posterior capsular opacification (PCO) in 10 of 11 patients where the capsule was left intact.
BCVA for the total group was a median of 20/30.
Inflammatory response can be severe when there is no compliance with postop medications. The instillation of steroids orally can greatly help restore good vision.
Patients with traumatic cataract appear to have a temporary pressure spike after cataract surgery, even with uncomplicated surgery.
Surgeons should also consider a scleral tunnel as opposed to a corneal tunnel.

Posted by afarahi at 10:28 AM

Refractive surgery in pediatric patients should be limited to selected cases, requires extreme care
A panel of surgeons discussed the many issues related to this matter, and offered different and sometimes ontrasting views.
OSN,July,2003

Refractive surgery in pediatric patients is still an open, problematic issue. Surgeons here debated the issue and reached a few consensus guidelines for approaching surgery in these patients.
We need to examine the many problems connected with this delicate matter, discuss opinions, compare results.
We have the duty to investigate all possible solutions, be active and proactive, but only within well limited boundaries and under the safest conditions possible.
Read more: (answers of these questions):
Who are the patients?At what age?Better with LASIK?Or PRK?Anesthesia?
The amount of correction?Phakic IOLs?Preventing problems?

Posted by afarahi at 10:00 AM