Ophthalmology Review

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January 31, 2006

Cytochrome c peroxidase significantly accelerates epithelial healing after PRK
JCRS OCT 2005
After uneventful bilateral photorefractive keratectomy for low to moderate myopia and myopic astigmatism, 36 patients (72 eyes) received the standard postoperative therapy plus cytochrome c peroxidase eyedrops in one eye (three times a day for one week or until corneal re-epithelialization was completed, corresponding to 15 000). The other eye received standard postoperative therapy plus placebo. All the eyes treated with cytochrome c peroxidase eyedrops healed completely before day 5 postop, with a mean re-epithelialization time of 91 hours ± 14 (SD), compared to 154 ± 9 in eyes receiving placebo. There were no statistically significant differences between the two groups in corneal haze presentation during follow-up (P =.70), which the authors conclude might be due to the short time period (seven days). But the authors note that corneal clarity on slitlamp biomicroscopy was greater in the study group than in the control group. No side effects or toxic effects were documented.

Posted by mtmdop at 11:32 AM | Comments (0)

More patient-friendly glaucoma regimen appears effective
Ophthalmology, January 2006
This 12-week, multi-center study included 517 patients with ocular hypertension, open-angle, pigmentary or exfoliation glaucoma and with baseline IOP levels (after washout) between 23 and 33 mmHg. Patients were randomized to receive either the fixed combination of latanoprost and timolol once daily in the evening and a placebo in the morning and evening or the unfixed combination of latanoprost once daily in the evening and timolol in the morning and evening. Researchers find the fixed combination of latanoprost and timolol administered once daily in the evening is not inferior to the unfixed combination of latanoprost once daily in the evening and timolol twice daily.

Posted by mtmdop at 11:18 AM | Comments (0)

Intraocular Lens Power Calculation Following LASIK: Determination of the New Effective Index of Refraction

JRS January/February 2006
To determine the new corneal effective index of refraction (rN) following LASIK to be used for accurate keratometry reading (K-reading).
A total of 332 eyes that underwent myopic LASIK were divided into two groups (group A [n=137] and group B [n=195]). In each group, patients were divided into four subgroups according to the amount of spherical equivalent refraction of myopic LASIK ablation (subgroup 1 [<-4.0 D], subgroup 2 [-4.0 to <-8.0 D], subgroup 3 [-8.0 to -12.0 D], and subgroup 4 [>-12.0 D]). In each subgroup of group A, K-reading was measured by the clinical history method and the new corneal effective index (rN) was determined using paraxial formula: (Kreading=( rN-1)/Ra), where Ra is the radius of curvature of the anterior corneal surface. In group B, the anterior radius of curvature of the cornea was determined by automated K-reading, and K-reading was measured in each subgroup using the new effective index in paraxial formula, clinical history method, and automated K-reading.
RESULTS
In group A, the new effective index of refraction was 1.3355, 1.3286, 1.3237, and 1.3172 in the four subgroups, respectively. In group B, the mean K-reading measurements using rN in paraxial formula, clinical history method, and automated K-reading were: 40.33±1.68 D, 40.33±1.67 D, and 40.54±1.69 D, respectively, in subgroup 1; 37.96±1.26 D, 38.03±1.38 D, and 38.98±1.28 D, respectively, in subgroup 2; 35.77±1.75 D, 35.84±1.85 D, and 37.29±1.83 D, respectively, in subgroup 3; and 34.03±1.49 D, 34.15±1.84 D, and 36.21±1.59 D, respectively, in subgroup 4. In all subgroups of group B, the results of K-reading obtained using the new effective index of refraction were statistically similar to the results obtained by clinical history method (P>.05). Automated K-reading statistically overestimated the K-reading values in subgroups 2, 3, and 4 of group B (P<.001).
CONCLUSIONS
The use of the new corneal effective index of refraction allows for an accurate derivation of K-reading from the anterior radius of curvature.

Posted by aman at 12:11 AM | Comments (0)

January 30, 2006

Confocal Microscopy of Disposable and Nondisposable Heads for the Moria M2 Microkeratome

JRS January/February 2006
To study the quality of the flap obtained with two different heads, disposable and nondisposable, and two different speeds, low and high, using the same Moria M2 microkeratome (Moria, Antony, France).
In a prospective randomized study, 51 consecutive eyes (28 patients) underwent myopic LASIK (-4.39±2.15 diopters). The eyes were randomly assigned to four groups related to cutting head model (disposable and nondisposable) and cut speed (low and high). In all cases, the intended cut was 160 µm and the same M2 unit was used. During surgery, superficial measurements of the flap and the surgeon’s opinion about the quality of the cut were recorded. One month after LASIK, the cut depth, interface particle density, and transparency of the cornea (confocal wound healing opacity index) were measured with a confocal microscope.
CONCLUSIONS
The Moria M2 microkeratome is safe and provided reproducible results, regardless of cutting head and speed. Disposable and nondisposable head models were similar in their outcome in the quality control model used in this study.

Posted by aman at 11:53 PM | Comments (0)

Posterior Capsule Opacity and Choroidal Neovascularization in Patients With Age-Related Macular Degeneration

Ophthalmic Surgery, Lasers and Imaging January/February 2006
Three consecutive patients aged 80 to 87 years (average = 83.7 years) with hard drusen or retinal pigment epithelial changes underwent uneventful cataract extraction between 6 months and 20 years before undergoing Nd:YAG capsulotomy for posterior capsule opacity. The patients were examined for retinal changes before laser treatment and at regular intervals after treatment.
All patients developed CNV between 12 days and 1 month after capsulotomy that caused a decrease in the visual acuity from 20/20—20/40 to 20/200—counting fingers at 4 feet. The fellow eye did not show a substantial change in AMD over a year of follow-up. Two of the fellow eyes had disciform scar due to CNV before the cataract surgery, and these patients remained legally blind.
CONCLUSIONS
The development of CNV after Nd:YAG capsulotomy suggests a temporal association between the two and calls for further study. Because posterior capsule opacity may mask CNV, patients with dry AMD and posterior capsule opacity who experience decreased visual acuity or glare may undergo indocyanine green angiography before it is decided to perform Nd:YAG capsulotomy.

Posted by aman at 11:46 PM | Comments (0)

Evaluation of the Potential Acuity Meter in Predicting Visual Acuity After Photodynamic Therapy for Choroidal Neovascularization

Ophthalmic Surgery, Lasers and Imaging January/February 2006
Retrospective study of 55 eyes in 51 patients with subfoveal predominantly classic choroidal neovascularization due to age-related macular degeneration. Pre-photodynamic therapy Snellen visual acuity minus the visual acuity with the potential acuity meter was compared with the actual improvement in visual acuity. Significant improvement in visual acuity after photodynamic therapy was defined as a gain of more than 2 lines in Snellen visual acuity (0.2 logarithm of the minimal angle of resolution units).
Eighteen (51.4%) of 35 eyes with a potential for improvement experienced an actual improvement in their Snellen visual acuity after photodynamic therapy (P < .001). All eyes lacking a potential for improvement failed to experience an actual improvement in visual acuity after photodynamic therapy.
CONCLUSION
The eyes that demonstrated better visual acuity with the potential acuity meter in this study seemed more likely to experience an improvement in visual acuity after photodynamic therapy.

Posted by aman at 11:39 PM | Comments (0)

January 29, 2006

AMD not accelerated by cataract surgery

Ophthalmology Times Jan 1, 2006
Observations of patients in the Age-Related Eye Disease Study (AREDS) after they had cataract surgery did not seem to show an accelerated progression to neovascular age-related macular degeneration (AMD) compared with patients matched for severity of AMD who did not have cataract surgery, reported Frederick L. Ferris III, MD, during retina subspecialty day at the American Academy of Ophthalmology annual meeting.
This study was prompted by the results of the Beaver Dam Eye Study and the Blue Mountain Eye Study, which, in a combined analysis, showed that there was about a five times increased risk of neovascularization in aphakic patients who were followed for 5 years; the Baltimore Eye Survey and the Proyecto VER similarly showed a increase in risk of about two times of the development of AMD .
Dr. Ferris and colleagues in the AREDS Research Group were able to evaluate the participants more precisely because they had yearly fundus photographs from the participants, outcome variables that were defined as either photocoagulation or changes in AMD on the fundus photographs, and they assessed the effects of cataract surgery every 6 months, he explained.
To surmount the problems encountered with population-based studies, the investigators studied the effects of cataract surgery in these patients using four statistical approaches to determine if there was an association between surgery and development of AMD: a Cox proportional hazards model using cataract surgery as a time-dependent covariate, repeated measures regression analysis, ordinary logistic regression analysis, and a matched case/ control approach, he said.
The median follow-up in this study was more than 6 years. The median patient age at baseline was 70 years, and 55% of patients were women.
About 73% of eyes had neither progression to advanced AMD nor cataract surgery; 19% had cataract surgery only; 5% had progression to advanced AMD only, and 2% of eyes had both events," he said. "Matched case/control analysis, Cox proportional hazards analysis, and regression analysis adjusted (or matched) for age, treatment assignment, baseline AMD status, and length of follow-up showed that cataract surgery did not significantly accelerate or was not associated with progression to neovascular AMD."

Posted by aman at 12:46 AM | Comments (0)

Angle Closure in Highly Myopic Eyes.

OPHTHALMOLOGY 2006 Jan 19
PURPOSE: Patients with angle-closure glaucoma and high myopia are uncommon. We evaluated the clinical characteristics of all patients with angle closure and high myopia in our database and propose possible mechanisms for angle closure in these atypical patients. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: Our database of 17938 patients was searched for patients with myopia of spherical equivalent of more than -6.0 diopters and angle closure. Data recorded included age at time of initial consultation, gender, slit-lamp examination results, gonioscopy results, biometric parameters, ultrasound biomicroscopy results (from 1993 onward), clinical diagnosis, and therapy. RESULTS: Twenty patients (11 females, 9 males) were identified. Mean age at the time of consultation was 52.9+/-19.3 years. Angle-closure diagnoses included primary pupillary block (9 patients), pupillary block in an eye with keratoconus (1 patient), pupillary block secondary to a pupillary membrane associated with retinopathy of prematurity (1 patient), plateau iris configuration and syndrome (3 patients), phacomorphic glaucoma in Weill-Marchesani syndrome (2 patients), malignant glaucoma secondary to a scleral buckle (2 patients), miotic-induced angle closure (1 patient), and Marfan syndrome (1 patient). CONCLUSIONS: Angle closure can occur in eyes with high myopia. Causes of angle closure other than relative pupillary block are more common than in the general angle-closure glaucoma population. Careful gonioscopy accompanied by biometry and ultrasound biomicroscopy can lead to the correct diagnosis and individualized management in these eyes.

Posted by aman at 12:13 AM | Comments (0)

Acanthamoeba Keratitis Clinical Characteristics and Management.

OPHTHALMOLOGY 2006 Jan 19
To review the clinical characteristics, treatment, and outcome of patients with Acanthamoeba keratitis (AK). DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Twenty consecutive patients with AK were referred to the Beijing Tongren Hospital, Capital University of Medical Science, China. METHODS: Retrospective analysis of medical records from 20 consecutive patients with AK between December 1, 1997 and March 30, 2003. Risk factors, laboratory investigations, clinical manifestations, treatments, and outcomes were analyzed. MAIN OUTCOME MEASURES: Best-corrected visual acuity (BCVA) at the end of follow-up. RESULTS: Of the 20 patients presented in this series, 12 patients were students and 6 were farmers. Risk factors included contact lens wear (12/20) and trauma (6/20). Corneal ulceration, diffuse stromal infiltration, and ring infiltration were the main clinical manifestations. The diagnosis of all patients was based on the laboratory investigation. Smear and culture positive specimens were 19 of 20 and 12 of 20, respectively. Images of cysts were demonstrated with confocal microscopy in 4 patients. Treatment was combined instillation of chlorhexidine (0.02%), neomycin (0.5%), metronidazole (0.4%), and/or lesion cauterization with chlorhexidine (1%), and corneal lesion debridement. The mean duration of therapy was 70 days (range, 18-150 days). Nineteen lesions healed with scar formation. The BCVA was better or equal to 20/100 in 7 eyes. CONCLUSIONS: Early diagnosis of AK is the key challenge in clinical practice. The combined use of antiacanthamoeba agents, debridement, and cauterization may be a best choice of treatment for patients who are diagnosed early in the course of their disease.

Posted by aman at 12:02 AM | Comments (0)

January 28, 2006

Alcohol Delamination of the Corneal Epithelium: An Alternative in the Management of Recurrent Corneal Erosions.

OPHTHALMOLOGY 2006 Jan 19
PURPOSE: To investigate the efficacy of alcohol delamination in the management of recurrent corneal erosions (RCEs). DESIGN: Prospective single-center consecutive descriptive case series. PARTICIPANTS: Twelve patients with RCEs who did not respond to conservative management were treated with alcohol delamination. METHODS: A consecutive case series of 12 patients with RCEs who did not respond to conservative management were treated by alcohol delamination. A pain score was generated based on a visual analog scale of pain intensity. The duration of pain and frequency were also recorded. Patients were followed up at 1 week, 4 weeks, 3 months, 6 months, and 1 year and then at yearly intervals and monitored for recurrence of symptoms and corneal morphology. The removed epithelial sheet was examined by electron microscopy in 4 patients. INTERVENTION: The affected area of epithelium was peeled off after an application of 20% alcohol for 40 seconds under topical anesthesia. Eyes of patients were treated with an antibiotic and preservative-free artificial tear medication, and a bandage contact lens was inserted until epithelial healing was complete. MAIN OUTCOME MEASURES: Frequency of recurrence of erosions and duration and intensity of symptoms after alcohol delamination were studied. RESULTS: Eleven of the 12 eyes of patients had dramatic relief of symptoms over the follow-up period, ranging from 6 to 40 months. Eight patients were symptom free, and 1 patient had 2 mild symptom episodes in the first posttreatment month before becoming symptom free. The average follow-up period was 23.5 months. There were no residual effects from the application of alcohol noted in any patient. Electron microscopy of removed epithelium showed features of the underlying pathology. The separation of the epithelium occurred at the interface of the subepithelial abnormal deposit and the surface of Bowman's zone. CONCLUSION: Alcohol delamination seems to be a novel, simple, inexpensive treatment for RCEs. Unlike other methods, the removed epithelium is available as a sheet that may be subjected to further examination, though some of the changes observed may reflect the effect of alcohol on the epithelium.

Posted by aman at 11:38 PM | Comments (0)

Detecting strabismus before refractive surgery

EYE WORLD
A detailed medical history and preoperative exam, including a motility evaluation, are essential to decrease strabismic problems and subsequent postoperative visual problems related to keratorefractive surgery (KRS), said Miles Burke, MD, associate professor at the University of Cincinnati. Ophthalmologists can use guidelines to determine the strabismic risks of KRS and develop a plan.
Strabismologists are becoming increasingly aware of a strabismic entity, primary microtropia, which is found in up to 5% of first-generation relatives of persons with infantile esotropia. Most individuals with primary microtropia escape detection because their minute misalignment is missed and their binocularity is nearly normal. Visual system stresses, like some of the ones caused by KRS, place these surgical candidates at a higher risk of developing postoperative problems, Burke said.
The first part of the medical history is to determine whether there has ever been a strabismic problem. If so, what type of therapy was undertaken? Make sure you ask whether anyone related to them has strabismus, especially infantile esotropia," he said
Searching for clues
Intermittent diplopia, fuzzy vision (with or without ghost images), and asthenopia with the possibility of convergence or accommodative insufficiency are red flags for potential strabismic concerns. Burke outlined the tests that should be included in the preoperative exam.
A check for prisms in the patient's glasses is needed. Careful manifest and cycloplegic refractions should also be performed. "Under manifest conditions in the myope, you must determine the minimum minus power necessary for their threshold maximum visual acuity. In the hyperope, both the minimum and the maximum plus power for maximum visual acuity must be measured," he said.
In addition, the muscle-balance exam should include the cover test. Cover and uncover one eye while observing the non-occluded eye for movement to detect a tropic misalignment. Then a deliberate alternate cover test should be performed. "This means a slow, continuous, back-and-forth covering of one eye, then the other eye, changing eyes at least five to six times, to break up fusion and uncover a phoria," he said.
Routine stereopsis and fusion-potential tests are recommended, as well as a check for unusual head positions and measurements in the primary, straight-face position.
Minimal risk
Minimal risk, or a no-risk patient, is the typical KRS candidate. Burke said that this patient is a myope who has not had any problems in glasses or contacts; who has no history of strabismus, diplopia, or other asthenopic complaints; and has no prisms in the glasses. For the minimal risk patient, the muscle-balance exam reveals a trivial phoria, and the patient possesses excellent binocularity. The manifest and cycloplegic refractions match within 0.5 D.
"Any patient who deviates from these parameters is at risk of developing strabismic and binocular function problems," he said.
Moderate risk
The moderate risk patient has prisms in his or her glasses.
Burke classifies all hyperopes at the moderate-risk level because of the frequent undercorrection of KRS and the regressions that appear to be more common in this subgroup. The undercorrected hyperope may develop accommodative esotropia and complain about premature presbyopia, therefore, the full hyperopic refractive error should be known before surgery.
Patients who have been surgically treated for strabismus are classified as moderate risk. Burke recommends that poststrabismic surgery patients be measured for their horizontal fusional vergence potential. "If they can hold up to a 10 prism diopters base in and base out without diplopia, I expect these patients to do well," he said.
Monovision is a moderate risk. "Many studies have shown that the threshold for loss of binocularity is a difference of only 1.25 D. The intraocular blur begins to cause suppression, resulting in stress that may break down fusional reserves, resulting in the development of a new strabismus," Burke said.
Research by Marshall Parks, MD, clinical professor, George Washington University, Washington, D.C., indicates that up to one-third of the surgically induced monovision patients will be converted from their normally bifixating status into a monofixational syndrome, with permanent loss of macular binocular vision. The shutdown of the bifixational reflex is suspected to occur in about 3 months, Parks said.
Burke estimates that 98% of the population has moderate to strong ocular dominance, which mean that many monovision patients will experience asthenopic complaints when forced to use the nonpreferred eye for some tasks. "In those patients who are already functioning in a monofixational situation from previous eye muscle surgery ... [as well as the] hidden primary microtropia patient, the change to monovision may precipitate frank double vision, by the loss of sensory adaptation or the loss of macular suppression in their nondominant eye. This may cause fixation-switch diplopia when [they are] forced to use their nondominant eye," he said.
Patients considering monovision should have a contact lens simulation of at least 3 weeks, with full muscle-balance testing and binocular functions reevaluated at the end of that time. "The best rule to follow for monovision is to keep the difference between the eyes to the absolute minimum," he said.
High risk
A small portion of patients, such as those with constant tropias, fall into the high-risk category and should receive a strabismic evaluation from a specialist.
Other high-risk patients include those who complain of intermittent double vision, ghost images, or visual confusion or stress (they may have a hidden strabismus), convergence insufficiency, or the infrequent problem of accommodative insufficiency not associated with presbyopia.
When the strabismologist examines the patient preoperatively, the eye-muscle problem has a chance to be corrected, or, at the very least, the extent of the risk of KRS may be more completely understood by the patient and the surgeon," Burke said.
Anisometropia of 4 D-plus places this patient at high risk, because of aniseikonia. When the corrected retinal image sizes are unequal, visual stress may impair motor fusion, resulting in the development of a new strabismus. Fixational-anomaly angle kappa is also an area of risk.

Posted by aman at 11:02 PM | Comments (0)

January 27, 2006

Recent advances in amblyopia

OSN OPHTHALMIC HYPERGUIDE
Several questions regarding amblyopia therapy remain. For example, guidelines regarding the amount of patching needed for improvement in visual acuity are based largely on anecdotal information or small, retrospective studies. 9-11,18-21

Another area of interest involves pharmacologic penalization. Although pharmacologic penalization has been shown to be an effective treatment for moderate amblyopia, 14,15,17,19 the relative efficacy of occlusion therapy vs. pharmacologic penalization has not been studied in large numbers.20

A multicentered National Institutes of Health-sponsored group, the Pediatric Eye Disease Investigator Group (PEDIG) is attempting to answer these and other questions by conducting a series of prospective, randomized clinical trials.

A paper published by the PEDIG5 looked at the characteristics of 409 patients with moderate amblyopia (20/40 to 20/100) who were 3 to 6 years of age. The group found equal numbers of patients with strabismic and anisometropic amblyopia. The level of visual deficit was the same regardless of etiology. The number of hours of prescribed patching varied among the eye care providers.

ATS1
In the Amblyopia Treatment Study 1 (ATS 1), the PEDIG6 looked at this same group with moderate amblyopia and compared atropine to patching (6 hours to all waking hours). The results indicated that vision improved faster in the group that patched but that the difference in visual acuity between the two groups after 6 months was not clinically significant. Researchers concluded that atropine and patching were acceptable treatments for children with amblyopia between 3 and 7 years of age.

ATS2
In the Amblyopia Treatment Study 2,22,23 the PEDIG conducted three randomized, controlled trials. The first trial looked at 3 to 6 year olds with moderate amblyopia (20/40 to 20/100). They compared 2 hours vs. 6 hours of patching. Patients performed 1 hour of near activities while patching. The results at 4 months showed that the vision improved to a similar extent in both groups.

A second study was conducted in patients between 3 and 6 years of age who had severe amblyopia (20/100 to 20/400). The group was randomized to patch 6 hours a day or full-time (all hours of the day or all hours except for 1). Each patient participated in 1 hour of near visual activities while patching. The visual acuity in both groups at 4 months was compared. The vision improved about 4.8 lines in the group that patched for 6 hours and 4.7 lines in the group that patched full-time.

The third trial 24 looked at 10 to 17 year olds with visual acuity ranging from 20/40 to 20/160. These patients were treated with patching for 2 or more hours. They participated in some type of activity at near for 1 hour. The visual acuity improved 2 or more lines in 27% (18 of 66 patients).

Posted by aman at 11:15 PM | Comments (0)

Stop the RNA’ and delay AMD progression

OSN BREAKING NEWS
A small interfering RNA compound has delayed the progression of age-related macular degeneration in early clinical testing, according to an investigator speaking here.
Peter K. Kaiser, MD, spoke about ophthalmic applications of short interfering RNA (siRNA) here at Retina 2006, held in conjunction with Hawaiian Eye 2006. He said that RNA proteins are what cause conditions such as AMD.
Dr. Kaiser described Sirna-027 from Sirna Therapeutics, a partially modified RNA that inhibits vascular endothelial growth factor. Sirna has described RNA interference as a natural selective process for turning off genes triggered by short interfering molecules that engage certain cellular proteins.
If you inject it into the vitreous, it might break down unstable RNA,” Dr. Kaiser said.
In a phase 1 study, Dr. Kaiser said, all 23 patients have “experienced stabilization of visual acuity, and 23% experienced visual improvement of three or more lines of visual acuity within 8 weeks of Sirna-027 injection.”
He said no serious adverse events or dose-limiting toxicities were observed
Dr. Kaiser said phase 2 studies of the drug are scheduled to begin in the first quarter of 2006. Sirna announced last year that it has partnered with Allergan to develop the compound for ophthalmic use.

Posted by aman at 10:29 PM | Comments (0)

Clinical evaluation of endothelial cell decrease with VisThesia in phacoemulsification surgery

JCRS Pages 2157-2161 (November 2005)
Italy,To assess the endothelial cell decrease after the use of sodium hyaluronate 0.3% and lidocaine hydrochloride 2% (VisThesia) to determine whether the addition of lidocaine 1% to sodium hyaluronate 1.5% makes the solution more toxic to the cornea.JHGVisThesia is an ophthalmic viscosurgical device (OVD) that incorporates lidocaine 1% to provide better comfort to patients under topical anesthesia. Fifty eyes 50 patients were operated on following the same patient selection and surgical technique. After the povidone–iodine (Betadine) ocular asepsis, 1 full ampoule of VisThesia Topical was applied over the corneal surface. The intracameral product was used as a routine OVD during the phacoemulsification procedure. The endothelium of the central cornea was examined preoperatively and 3 months after surgery using a noncontact endothelium microscope.

Results
At the last follow-up visit,BCVA was 0.88 and the mean MRSE was −0.36 D. The mean endothelial cell density had decreased from 2363.57 ± 435.4 cells/mm2 preoperatively to 2222.6 ± 537.69 cells/mm2 at 3 months. These values are comparable with results obtained in other investigations published in the literature using other, similar OVD.

Conclusions
The results observed in this investigation indicate that the addition of lidocaine to the sodium hyaluronate in VisThesia does not induce additional toxicity nor does it result in increased endothelial cell loss when compared with other, similar OVDs.

Posted by alireza habibollahi at 07:32 PM | Comments (0)

Comparison of higher-order wavefront aberrations with 3 aberrometers

JCRS Pages 2153-2156 (November 2005)

To evaluate the agreement of higher-order aberrations (HOAs) between aberrometers based on the Hartmann-Shack wavefront technology.
Three clinical aberrometers WaveScan (Visx Inc.), LADARWave (Alcon Inc.), and Zywave (Bausch & Lomb Inc.) were used to measure HOAs in 34 cycloplegic eyes in 17 subjects. All the measurements in each subject were performed in 1 visit to reduce the impact of biologic fluctuation of HOAs. Each device was operated by an independent experienced operator, and the operators were blind to the data obtained from the other aberrometers. Root mean square (RMS) of coma, spherical aberration, and total 3rd- and 4th-order HOAs were compared between any 2 devices by a paired t test.
Results
WaveScan had the lowest mean RMS, whereas Zywave reported the highest mean RMS for any HOAs.In general, the largest discrepancies of HOA measures were between WaveScan and Zywave, and similar data were found between LADARWave and WaveScan. More than 80% of the absolute difference of HOA RMS between LADARWave and WaveScan, 50% to 78% between LADARWave and Zywave, and 38% to 59% between WaveScan and Zywave were within ±0.1 μm.

Conclusions
Significant discrepancies in HOA measurements were found among the 3 popular aberrometers. The HOA RMS data were closer between LADARWave and WaveScan, and HOA RMS by Zywave was generally higher than the other 2 devices. The 3 devices had comparable measurement variation.

Posted by alireza habibollahi at 07:25 PM | Comments (0)

Phacofragmentation with perfluorocarbon liquid and anterior chamber or scleral-fixated intraocular lens implantation for the management of luxated crystalline lenses

JCRS Pages 2147-2152 (November 2005)
Poland.To present a complex surgical technique used for the management of luxated crystalline lenses and evaluate treatment results.
This prospective study involved 29 consecutive patients (30 eyes) with the mean age of 60.3 years. The applied surgical technique comprised pars plana vitrectomy, perfluorocarbon liquid injection, and crystalline lens phacofragmentation in the vitreous cavity. Simultaneously, AC-IOLs were implanted in 10 eyes, and scleral-fixated posterior chamber IOLs in 20 eyes. The follow-up mean was 5.2 month
Results
No complications were observed during phacofragmentation. Visual acuity improved in 22 cases and did not change in the other 8 eyes. The mean visual acuity was 0.40 (range between hand movements and 1.0) pre-op and 0.68 (range 0.05 to 1.0) postoperatively. In 22 cases (73%), very good or good visual acuity (6/6 to 6/12) was achieved. There were no intraoperative complications. Postoperatively, transient hypotony was observed in 10 eyes, fibrinous reaction in the anterior chamber in 1 eye, dispersed blood in the vitreous cavity in 8 eyes, hyphema in 1 eye, corneal edema in 1 eye, vitritis in 3 cases, iris tug in 1 eye with an anterior chamber IOL, and slight dislocation of the scleral-fixated IOL in 1 case. Intraocular pressure was elevated in 11 eyes preoperatively; postoperatively, it normalized in 7 eyes without medication.

Conclusion
Phacofragmentation with perfluorocarbon liquid and IOL implantation for the management of luxated crystalline lenses was safe and effective method, providing good functional results.

Posted by alireza habibollahi at 07:18 PM | Comments (0)

Shallow ablations in PTK : Long-term follow-up

JCRS Pages 2133-2136 (November 2005)
China,To evaluate the long-term efficacy and safety of shallow ablations in PTK in patients with recurrent corneal erosions.

A retrospective analysis of 13 consecutive eyes with recurrent corneal erosions treated by PTK from 1997 to 1999 was performed. All eyes failed to respond to conventional treatments, and all eyes had corneal erosions involving the visual axis. Outcome measures included number of recurrences, BCVA and SE, and complications arising from the laser treatment.
Results
Indications for PTK were recurrent corneal erosions secondary to minor abrasive trauma (9 eyes) and map-dot-fingerprint corneal dystrophy (4 eyes). The mean ablation depth was 4.6 μm (range 3.4 to 5.8 μm). Mean post-op follow-up was 49.5 months .The overall success rate after only 1 treatment was 84.6%. Eleven of 13 eyes had a preserved or improved BCVA, while 2 eyes showed deterioration of 1 line on Snellen testing. Seven of 13 patients had no change in SE; the rest had a change of less than ±0.50 diopters. There were no major complications.

Conclusions
The comparable success rate after a single treatment suggests that PTK may still be effective at a shallower depth than previously considered. Shallow ablations may have lower chances of complications associated with deeper ablations. Further studies involving a larger number of subjects are warranted.

Posted by alireza habibollahi at 07:01 PM | Comments (0)

Discriminative power of reading tests to differentiate visual impairment caused by cataract and ARMD

JCRS Pages 2111-2119 (November 2005)

The high discriminant accuracy shows that standardized reading test system is a valuable diagnostic tool for evaluating functional visual impairments when distance visual acuity alone cannot elucidate the origin of functional impairment. Considering the significant discrepancies in reading performance among patients with nuclear cataract, posterior subcapsular cataract, and ARMD, reading tests may relevantly improve the clinical evaluation of patients with visual loss, even of patients with ocular comorbidity.

Posted by alireza habibollahi at 06:49 PM | Comments (0)

Viagra, Cialis linked again to vision loss

British Journal of Ophthalmology, February 2006
This retrospective study included 38 males with non-arteritic anterior ischaemic optic neuropathy (NAION) identified from an academic ophthalmology practice in Birmingham, Ala. and 38 age-matched controls without a history of NAION. The authors found that patients taking Viagra and/or Cialis who also had a history of heart attack were almost 11 times more likely to develop NAION than patients who had no similar heart history and did not take either medication. Though the association is strong, the researchers are cautious about making clinical recommendations to any patients based on a small, retrospective study. For now, they conclude patients whose medical background includes heart attacks or high blood pressure be informed about the possible connection to NAION when the drugs are prescribed. In other Viagra news, researchers from the Institute of Ophthalmology in London report that the drug may be useful for vision research. They have demonstrated that therapeutic 100 mg doses of Viagra cause transient losses in the sensitivity to flicker. They say the work sheds light on the function of a specific photoreceptor enzyme and paves the way for future research.

Posted by kjalali at 02:11 PM | Comments (0)

An optimum screening strategy for retinopathy of prematurity

JAAPOS, December 2005
This British study included 187 infants with either a birth weight less than 1,500 g or gestational age less than 32 weeks screened for ROP during an eight-year period. Although there was a slight increase in the number of infants screened over the years, the incidence of ROP of any stage remained stable. All infants with threshold ROP had a birth weight less than 1,100 g and gestational age less than or equal to 28 weeks. Significantly fewer babies (56 percent) would have been examined had inclusion criteria of a birth weight of less than 1,251 g and gestational age less than 30 weeks been applied. In addition, 31 percent of screening examinations could have been avoided. The authors conclude that a birth weight of less than 1,251 g and gestational age less than 30 weeks can be safely and efficiently used to screen infants without missing a diagnosis of sight-threatening ROP.

Posted by kjalali at 02:10 PM | Comments (0)

Herbal medicines are ineffective in treating common eye diseases

American Journal of Ophthalmology, January 2006
This retrospective review of literature published in PubMed, the International Bibliographic Information of Dietary Supplements and selected Web sites finds no evidence to support the use of herbal medicines to treat AMD, cataract, diabetic retinopathy or glaucoma. Researchers did find evidence to support the use of certain vitamins and minerals in patients with certain forms of AMD, but no evidence of their effectiveness in treating or preventing cataracts, diabetic retinopathy or glaucoma. The authors encourage ophthalmologists to educate themselves about these alternative therapies so they can properly inform their patients.

Posted by kjalali at 02:08 PM | Comments (0)

IOP monitoring following Macugen injections may be unnecessary

American Journal of Ophthalmology, January 2006
This retrospective review of 79 patients receiving pegaptanib injections (122 consecutive injections) finds the mean IOP change from baseline to roughly 30 minutes after injection was 8.74 ± 7.23 mm Hg. At the five to seven-day follow-up visit, IOP had normalized. Researchers conclude that pegaptanib injections don’t affect IOP in the short-term.

Posted by kjalali at 02:07 PM | Comments (0)

PC IOL provides better visual outcomes for patients with vitreous presentation during cataract surgery

American Journal of Ophthalmology, January 2006
This prospective study conducted at 19 Department of Veterans Affairs medical centers randomized 438 patients with vitreous presentation (VP) during extracapsular cataract surgery and with sufficient capsular support to receive a PC IOL (230) or an AC IOL (208). At one year follow-up, 91 percent receiving the PC IOL had a BCVA of 20/40 or better, compared to only 79 percent in the AC IOL group. In addition to the VP patients randomized to receive either the PC IOL or the AC IOL and a random sample of non-VP patients, a third group that suffered VP but lacked sufficient capsular support for any nonsutured PC IOL (143 patients) was also prospectively followed. The insufficient capsular support group had considerably fewer patients with BCVA of 20/40 or better at 1 year (P < .0001) than either the randomized PC IOL or AC IOL groups. The authors conclude that patients who suffer VP without sufficient capsular support for a nonsutured PC IOL have poorer vision above what would be accounted for by having an AC IOL instead of a PC IOL implanted.

Posted by kjalali at 02:06 PM | Comments (0)

A Novel Approach to Re-pegging Hydroxyapatite Implants Using Bioactive Glass.

Ophthalmic Plastic & Reconstructive Surgery. January/February 2006.
Over a 2-year period, 3 patients with pegged hydroxyapatite orbital implants and related complications that did not respond to conservative treatment, underwent removal of the implant pegs and/or sleeves. Peg tracts were subsequently filled with bioactive glass.
No complications occurred in any case during 3 years of follow-up. After 2 months, 2 patients underwent successful re-drilling of the peg site and insertion of titanium pegs. Both patients were satisfied with the results. The third patient has deferred re-pegging at this time.
Conclusion: Bioactive glass is effective for refilling old peg tracts and allowing timely re-pegging of hydroxyapatite implants.

Posted by afarahi at 12:44 AM | Comments (0)

Adverse Reactions to Permanent Eyeliner Tattoo.

Ophthalmic Plastic & Reconstructive Surgery.January/February 2006.
An observational case series was conducted on 4 patients who presented with inflammatory eyelid reactions after receiving permanent eyeliner tattoo.Clinically, the tattoo-associated lesions were typically firm, raised masses underlying the areas of pigmentation. Histopathologic analysis of tissue from all 4 patients demonstrated a granulomatous inflammatory response with negative cultures for any organisms. Treatment approaches varied between a combination of topical steroid creams, local steroid injections, local resection, intramuscular steroid injection, and systemic oral steroids. These treatments were successful in all 4 cases.
Conclusions: An allergic granulomatous reaction is one of the adverse reactions seen after permanent eyeliner tattoo. Treatment can be challenging and may ultimately require excision of tattoo pigment to remove the inciting factor. Systemic steroids may aid in controlling the inflammation associated with reaction to the tattoo pigment.

Posted by afarahi at 12:41 AM | Comments (0)

Mersilene Mesh Versus Sclera in Wrapping Hydroxyapatite Orbital Implants.

Ophthalmic Plastic & Reconstructive Surgery. January/February 2006.Kassaee, Abolfazl M.D. *; Kashkouli, Mohsen Bahmani M.D. +; Panjtanpanah, Mohammadreza M.D. *; Sadeghi, Ali M.D. *; Tabatabaee, Ziaeddin M.D. *
In a prospective, randomized, interventional comparative case series, 60 eyes from 60 consecutive patients were included and randomly allocated for primary enucleation and either Mersilene mesh-wrapped hydroxyapatite (MHA) orbital implant (30 cases, 50%) or sclera-wrapped hydroxyapatite (SHA) orbital implant (30 cases, 50%) under general anesthesia. Complete socket examination was performed at 1 week, 1 month, and then every 3 months after surgery.
The most common cause of enucleation was trauma in both groups (P = 0.09). Patients with MHA had significantly (P =0.005) longer follow-up time (mean, 11.40 months) than those with SHA (mean, 9.40 months). No exposure was found at last follow-up in the MHA group, but one patient in the SHA group had a small exposure (1 x 1 mm) 1 month after surgery that was conservatively treated. There were no significant postoperative soft tissue complications in either group.
Conclusions: Sclera and Mersilene mesh could be used as a wrapping material for hydroxyapatite orbital implants without significant complications. Absence of disease transmission, low cost, and availability are the main advantages of Mersilene mesh.

Posted by afarahi at 12:34 AM | Comments (0)

Clinical Features and Treatment of Graves Ophthalmopathy in Pediatric Patients

Ophthalmic Plastic & Reconstructive Surgery.January/February 2006.
Retrospective case series identifying patients 18 years or younger in whom Graves ophthalmopathy was diagnosed from 1985 through 1999. The 35 children with Graves ophthalmopathy included 27 girls (77.1%) and 8 boys (22.9%). At the time of initial ophthalmic examination, 31 patients (88.6%) were hyperthyroid, 1 (2.9%) was hypothyroid, and 3 (8.6%) were euthyroid. The mean age at diagnosis of thyroid dysfunction was 13.1 years (range, 3 to 18). The mean age at diagnosis of ophthalmopathy was 15.0 years (range, 5 to 18). No patient had compressive optic neuropathy. Thirty-one patients (88.6%) required no therapy or only supportive therapy. One patient (2.9%) required eyelid surgery and 3 (8.6%) underwent transantral orbital decompression for proptosis that caused discomfort and exposure keratitis. No patient received systemic corticosteroids or orbital radiotherapy. A follow-up survey was returned by 20 respondents at a mean follow-up of 11.0 years after the initial examination (range, 3.4 to 19.4). One patient (5.0%) had undergone eye muscle surgery. All patients stated that their vision was good, and 19 (95.0%) had no diplopia. Two patients (10.0%) reported that family members had Graves ophthalmopathy, and 12 (60.0%) had family members with thyroid dysfunction.
Conclusions: The clinical manifestations of Graves ophthalmopathy are relatively less severe in pediatric patients. Surgical therapy is infrequently necessary.

Posted by afarahi at 12:20 AM | Comments (0)

January 24, 2006

Excimer laser surgery for correction of ametropia after cataract surgery

JCRS Pages 2104-2110 (November 2005)
35 of 60
USA.Using the Visx Star excimer laser system mean of 47 months after cataract extraction with IOL implantation. Except for 1 patient with a silicone plate lens, all patients received 3-piece poly(methyl methacrylate) lenses. The mean age at time of excimer treatment was 75 years .PRE-OP SE was −3.76 D ,sphere −9.00 D to plano, and the highest cylindrical 5.50 D. At last follow-up the MRSE was −0.88 D Changes in MRSE were highly significant . There was no difference between targeted and achieved postoperative refraction .Increasing age was correlated with a hyperopic shift .All patients were satisfied with their final UCVA, which improved in every case. Except for 1 patient in whom an epiretinal membrane developed, BSCVA remained unchanged or improved.

Conclusions
In this series of patients, who were a few decades older than the typical excimer laser candidate, laser refractive surgery was a safe, effective, and predictable method to correct ametropia after cataract IOL.It may be a viable, noninvasive alternative to intraocular surgery, which has potential complications. Although satisfactory for all patients, final UCVA was not as high as that reported in laser refractive surgery patients in general, and this result may be because of prior cataract extraction with IOL implantation or increased age.

Posted by alireza habibollahi at 09:55 PM | Comments (0)

Refractive results with secondary piggyback implantation to correct pseudophakic refractive errors

JCRS Pages 2101-2103 (November 2005)

To assess the efficacy and safety of implanting a second intraocular lens (IOL) to correct pseudophakic refractive errors.
Methods
This prospective noncomparative case series included 10 pseudophakic eyes, 5 with a myopic residual refractive error and 5 with a hyperopic residual refractive error. All eyes had secondary piggyback IOL implantation with the IOL placed in the ciliary sulcus. Five types of IOLs were used to correct the residual refractive error.
Results
The mean preoperative myopia was −6.6 diopters and the refractive outcome was within 0.5 ± 0.7 D of the desired refraction (range –1.5 [undercorrected] and +1.0 D [overcorrected]). The mean preoperative hyperopia was +3.8 D, and the refractive outcome was within 0.46 ± 0.4 D of the desired refraction (range 0 and 1.0 D overcorrected). All patients showed visual acuity improvement. Best spectacle-corrected visual acuity improved from 20/44 to 20/30 (P<.05).

Conclusion
An IOL type that is appropriate for implantation in the ciliary sulcus is a viable option for correcting pseudophakic refractive error using the piggyback technique.

Posted by alireza habibollahi at 09:51 PM | Comments (0)

LASIK outcomes following RK, AK, PRK, and PKP

JCRS Pages 2093-2100 (November 2005)
A Moria LSK-1 microkeratome was used with a Visx S2 or Wavelight Allegretto excimer laser. Data were acquired by retrospective chart review of all appropriately qualified patients.
Results
The mean pre-op MRSE was −3.93 D in myopic eyes and +1.43 D in hyperopic eyes. The mean time from the initial corneal surgical procedure to LASIK was 65.0 months. The mean post-LASIK follow-up was 9.40 months .Post-op MRSE was −0.85 ± 1.42 D in myopic eyes and −0.16 D in hyperopic eyes . Enhancement by LASIK was required in 14% of eyes.

Conclusion
In eyes that have had a variety of previous corneal surgeries, LASIK offers a safe and predictable method for enhancing refractive results.

Posted by alireza habibollahi at 09:43 PM | Comments (0)

Blue-light filtering intraocular lens in patients with diabetes: Contrast sensitivity and chromatic discrimination

JCRS Pages 2088-2092 (November 2005)

To evaluate potential changes in contrast sensitivity and color discrimination in diabetic patients who had cataract surgery and implantation of the blue-light filtering AcrySof Natural (SN60AT) intraocular lens (IOL) compared with an ultraviolet-only filtering (AcrySof SA60AT) IOL.
Methods
Forty-four eyes of 22 diabetic patients were enrolled in a blue-light filtering fellow-eye control study. Patients received yellow-tinted IOLs (AcrySof Natural) in 1 eye and non–yellow-tinted IOLs (AcrySof SA60AT) in the fellow eye. Three months after surgery, monocular contrast sensitivity function was measured with the CSV 1000-E contrast sensitivity chart at distance and color discrimination was tested with the Farnsworth-Munsell 100-hue test.
Conclusions
In diabetic patients, the AcrySof Natural IOL provides better contrast sensitivity than the AcrySof SA60AT. The blue-light filter of the AcrySof Natural IOL did not cause chromatic discrimination defects based on total error scores and improved color vision in the blue–yellow chromatic axis in diabetic patients

Posted by alireza habibollahi at 09:36 PM | Comments (0)

Effect of anterior capsule polishing on posterior capsule opacification and neodymium:YAG capsulotomy rates: Three-year randomized trial

JCRS Pages 2067-2075 (November 2005)

Vienna, Austria,To compare the long-term effect of extensive polishing and nonpolishing of the anterior lens capsule on posterior capsule opacification (PCO) and neodymium:YAG (Nd:YAG) capsulotomy rates.
108 eyes of 54 consecutive patients with age-related cataract. Following phacoemulsification, 3-piece intraocular lenses (IOLs) with round-edged silicone optics were implanted. Patients received an Allergan SI-40 IOL with a truncated, round optic edge or a Domilens Silens6 IOL with a fully round optic edge. Patients were randomly assigned to have extensive anterior capsule polishing with the Menapace aspiration curette or no treatment in the first eye; the second eye received the opposite treatment. Digital retroillumination images were taken at 1 week, 1 year, and 3 years, and Nd:YAG capsulotomy rates were evaluated. Posterior capsule opacification was objectively scored using automated image analysis software (AQUA) or estimated based on clearly defined assumptions if a capsulotomy had been performed.

Results
Thirty-nine patients (78 eyes) concluded the study. Three-year PCO scores after polishing did not differ significantly (P>.05). However, 21 polished eyes (53.8%) required Nd:YAG laser capsulotomy compared with 14 nonpolished eyes (35.9%). The mismatch between PCO scores and Nd:YAG rates resulted from a change in PCO morphology that is not detected by scoring methods based on retroillumination photography but is visually disturbing to patients.

Conclusions
Polishing the anterior capsule was effective in reducing fibrotic opacification but ineffective in reducing regeneratory opacification. Changes in regeneratory PCO morphology not picked up by retroillumination photography increased the need for Nd:YAG laser capsulotomy.

Posted by alireza habibollahi at 09:30 PM | Comments (0)

Iris reconstruction with a multipiece endocapsular prosthesis in iridocorneal endothelial syndrome

JCRS Pages 2051-2054 (November 2005)
Iris reconstruction in cases of iridocorneal endothelial (ICE) syndrome is extremely challenging because of the nature of the iris tissue, which is typically friable and poorly suited to suture repair. Reconstruction in such cases often requires artificial iris implantation. This report illustrates cataract extraction and iris reconstruction with a multipiece endocapsular iris prosthesis that can be inserted through a small incision. Maintenance of a small incision size is a distinct advantage when glaucoma is coexistent in patients with ICE syndrome. It also demonstrates the presence of an ICE membrane over the anterior capsule and the importance of recognizing this membrane rather than confusing it with the anterior capsule when performing the capsulorhexis.

Posted by alireza habibollahi at 04:29 PM | Comments (0)

January 23, 2006

DIURNAL VARIATION IN CLINICALLY SIGNIFICANT DIABETIC MACULAR EDEMA MEASURED BY THE STRATUS OCT

RETINA
To investigate diurnal variation in clinically significant macular edema (CSME) using the Stratus OCT (Carl Zeiss Meditec), fifteen eyes of 15 diabetic patients with CSME and 10 healthy subjects (controls) underwent four optical coherence tomography (OCT) measurements of macular thickness. Mean retinal thickness remained unchanged in all retinal sectors over the course of the day for the controls and the 6 diabetic patients with a baseline foveal thickness of <300 [mu]m, and it significantly decreased in 7 of the 9 retinal sectors for the 9 diabetic patients with a baseline foveal thickness of >=300 [mu]m (ANOVA model for repeated measures). In these patients, the mean initial foveal thickening +/- SD of 211 +/- 104 [mu]m was reduced by an average of 6.1%, 15.2%, and 21.2% at 12 pm, 3 pm, and 6 pm, respectively. Two of these nine patients also had an increase in visual acuity without change in refraction. There were no changes in refractive errors over the course of the study in the two groups. A positive correlation between initial central thickening and decrease in thickness was found (r = 0.732; P= 0.002). This study suggests that macular thickening, as measured by the Stratus OCT, may spontaneously decrease in some patients with more severe CSME over the course of the day, and it confirms previous findings. However, in our study, the entity of this decline was relatively small and not relevant from a clinical standpoint.

Posted by kjalali at 08:57 PM | Comments (0)

PARS PLANA VITRECTOMY WITH AND WITHOUT PEELING OF THE INNER LIMITING MEMBRANE FOR DIABETIC MACULAR EDEMA

RETINA
In a prospective, comparative, nonrandomized study to evaluate the efficacy of pars plana vitrectomy (PPV) with and without inner limiting membrane (ILM) peeling for persistent diffuse clinically significant macular edema, eighteen patients with persistent diffuse clinically significant macular edema despite laser photocoagulation were recruited for the study. Patients with ILM peeling had improvement in foveal thickness (P = 0.07) and significant improvement in the macular volume (P = 0.039) 12 months after surgery but did not have significant improvement in Early Treatment Diabetic Retinopathy Study vision or perifoveal cone function. There was no significant difference in outcome parameters between the no peeling group and the ILM peeling group. In this prospective, comparative study of PPV with and without ILM peeling for diffuse clinically significant macular edema, structural improvement was seen but with limited visual improvement after ILM peeling

Posted by kjalali at 08:49 PM | Comments (0)

Three Methods of Measuring Corneal Thickness and Anterior Chamber Depth
American Journal of Ophthalmology
January’s Issue

Accurate measurement of corneal thickness and anterior chamber depth enhances the evaluation and treatment of many disease processes or procedures. Buehl et al. compared three different methods of measuring corneal thickness (CT) and anterior chamber depth (ACD) in a prospective clinical trial.

Central corneal thickness (CCT), CT at four peripheral points, and central ACD were measured in 88 eyes of 44 healthy subjects with the Pentacam (rotating Scheimpflug camera; Oculus), Orbscan I (scanning slit topography system; Orbtek), and ACMaster (partial coherence interferometry; Carl Zeiss Meditec).

The upper (lower) limits of agreement for CCT measurements were 7.9 micrometers between ACMaster and Pentacam, 17.6 µm between ACMaster and Orbscan, and 25.2 µm between Pentacam and Orbscan. Correlation was high between all three methods. The upper and lower limits of agreement for ACD were 0.174 millimeters between ACMaster and Pentacam, 0.406 mm between ACMaster and Orbscan, and 0.384 mm between Pentacam and Orbscan. Correlation was high between the three methods. Correlation was lower for the CT measurements at the four peripheral points.

The CCT and ACD values obtained by Pentacam, Orbscan and ACMaster measurements correlated well and showed few outliers. The two new systems—Pentacam and ACMaster—seem to provide a reliable, easy-to-use, noncontact method of measuring CCT and ACD. Larger differences occurred only when measuring peripheral CT values, especially between ACMaster and the other two methods

Posted by mtmdop at 01:14 AM | Comments (0)

Coffee No, Neckties Yes for Glaucoma PatientsJournal of Glaucoma
2005;14:504–507 and 2005;14:508–510

According to two reports in the Journal of Glaucoma, glaucoma patients may want to avoid caffeine but can wear a tight necktie without worrying about elevating IOP.

The first report, by Shandrasekaran et al., used data from The Blue Mountain Eye Study, to examine a possible relationship between coffee or caffeine intake and IOP in 3,654 participants age 49 and older living west of Sydney, Australia.

The researchers found after multivariate adjustment that individuals with open-angle glaucoma who drank coffee regularly had a significantly higher mean IOP (19.63 mmHg) than participants who did not drink coffee regularly (16.84 mmHg). Similar findings held true for caffeine intake. However, no association was found between coffee or caffeine consumption and higher IOP in those with ocular hypertension or those without open-angle glaucoma.

In the second report by Talty and O’Brien, a prospective study of 18 normal and 19 primary open-angle glaucoma patients investigated the effect of tight neckties on IOP. Interestingly, while a significant increase in IOP (1.58 mmHg) was detected after three minutes of tight necktie wear in the glaucoma group, IOP decreased significantly (0.94 mmHg) after 12 further minutes of tight necktie wear. Given these findings, the authors concluded that necktie wear does not pose a health threat to glaucoma patients.

Posted by mtmdop at 01:10 AM | Comments (0)

Serum Inflammatory Markers in Diabetic Retinopathy
Investigative Ophthalmology & Visual Science
2005;46:4295–4301

A study by Meleth et al. looking at serum inflammatory markers suggests evidence to support the role of inflammation in the pathogenesis of diabetic retinopathy.

A variety of serum factors were examined in 93 participants. Stromal cell-derived factor-1alpha and (RANTES)/CCL5 were significantly elevated in patients with at least severe nonproliferative diabetic retinopathy compared with those with less severe diabetic retinopathy. Positive immunostaining was observed in the inner retina for monocyte chemoattractant protein-1/CCL2 and RANTES of the patient with diabetes. Staining was strongly positive throughout the diabetic retina for the intercellular adhesion molecule-1/CD54. In contrast, normal retinal tissues showed little reactivity.

The authors conclude that these findings point to the role chemokines, cytokines and cell adhesion molecules play in the development of diabetic retinopathy and serve as a potential risk assessment tool in this population. However, further studies are necessary to establish a conclusive link between these molecules and diabetic retinopathy.

Posted by mtmdop at 01:06 AM | Comments (0)

Recovery of Corneal Subbasal Nerve Density After PRK and LASIK
American Journal of Ophthalmology
December’s Issue

Severing the corneal nerves during refractive surgery may have short- or long-term effects on the health of the cornea. Erie et al. measured and compared the return of corneal innervation up to five years after PRK and LASIK in a prospective, nonrandomized clinical trial.

Eighteen eyes of 12 patients received PRK to correct a mean refractive error of –3.73, and 16 eyes of 11 patients received LASIK to correct a mean refractive error of –6.56. Corneas were examined by confocal microscopy before and at one, two, three and five years after the procedures. Subbasal nerve fiber bundles were measured to determine density (visible length of nerve/frame area) and were expressed as micrometers
per square millimeter.

After PRK, mean subbasal nerve density was reduced by 59 percent at one year when compared with preoperative density. By two years, subbasal nerve density was not significantly different from density before PRK and remained unchanged to five years. After LASIK, subbasal nerve density was reduced by 51 percent, 35 percent and 34 percent at one, two and three years, respectively. By five years, subbasal nerves had returned to densities that were not significantly different from densities before LASIK.

Corneal subbasal nerve density does not seem to recover to near-preoperative densities until five years after LASIK, as compared with two years after PRK.

Posted by mtmdop at 12:59 AM | Comments (0)

Alkali-Induced Corneal Stromal Melting Prevention by a Novel Platelet-Activating Factor Receptor Antagonist

ARCHIVES Vol. 124 No. 1, January 2006
To evaluate the effect of LAU0901 (2,4,6-trimethyl-1,4-dihydropyridine-3,5-dicarboxylic acid ester), a novel platelet-activating factor (PAF) receptor antagonist, on a rabbit model of severe corneal alkali injury.
Adult New Zealand albino rabbits were anesthetized and the right eyes were injured with 2N sodium hydroxide for 60 seconds using a 12-mm plastic well, then rinsed. After the injury, 10 rabbits were treated topically with LAU0901 every 2 hours 4 times per day and received a subconjunctival injection of 200 µL of LAU0901 once per week and 10 rabbits were treated with vehicle the same way. Over the course of 4 weeks, the corneas were examined daily by slitlamp microscopy and corneal ulcers were graded with a clinical scoring system. Ten additional rabbits were treated as described but 1 rabbit from each group was killed at 1, 3, 7, 14, or 21 days after injury. The corneas were processed for histopathologic and immunofluorescence examination.
Conclusions LAU0901 inhibits corneal ulceration and perforation in a severe alkali-burn model in the rabbit. In the cornea, PAF is a strong inflammatory mediator, a chemotactic to inflammatory polymorphonuclear leukocytes, and an inducer of several proteases that degrade the extracellular matrix.

Posted by aman at 12:59 AM | Comments (0)

Mitomycin C augmented glaucoma surgery: evolution of filtering bleb avascularity, transconjunctival oozing, and leaks

BJO February 2006
To prospectively study the evolution of possible high risk features of conjunctival filtration blebs like avascularity, transconjunctival oozing (TCO), and leaks after mitomycin C (MMC) enhanced glaucoma surgery.
Single observer, 2 year prospective study on bleb characteristics of 125 eyes of 125 consecutive patients who had MMC augmented glaucoma surgery with initially successful filtration. MMC (0.2 mg/ml for 2 minutes in most cases) was applied on the area of the scleral flap before dissection. Glaucoma surgeries included were trabeculectomy, deep sclerectomy, and combined procedures. A dry fluorescein strip was applied on the avascular part of the bleb and observed for aqueous egress with flow (point leak, PL) or without (TCO).
Conclusions: MMC application over the area of scleral flap dissection during glaucoma surgery is associated with a high incidence of bleb avascularity, TCO, and delayed bleb leaks. Most eyes developed bleb avascularity within the first year after surgery. TCO will eventually be seen in all eyes with avascular blebs and the incidence of leaks gradually increases with time. This study shows that patients with eyes undergoing glaucoma surgery with MMC and avascular blebs should be monitored indefinitely.

Posted by aman at 12:48 AM | Comments (0)

Acanthamoeba Shows Affinity for First-Generation Silicone Hydrogel Contact Lenses
Ophthalmology
January's issue

Two brands of silicone hydrogel (S-H) lens were introduced in the late 1990s: the PureVision lens, composed of balafilcon A, and the Focus Night & Day lens, composed of lotrafilcon A. Recently, Acuvue Advance, a “second-generation” S-H lens composed of galyfilcon A, was introduced.

Beattie et al. incubated unworn, worn and Pseudomonas aeruginosa biofilm-coated first- and second-generation S-H and conventional hydrogel lenses for 90 minutes in suspensions of plate-cultured Acanthamoeba castellanii trophozoites. Acanthamoeba demonstrated a greater affinity for the first-generation S-H lenses compared with the second-generation S-H and the conventional hydrogel lenses.

Prospective studies are needed to determine if these findings are of clinical significance since only one suspected case of Acanthamoeba has been reported in more than one
million global patient years of wear.

Posted by mtmdop at 12:44 AM | Comments (0)

Microbial contamination of preservative free eye drops in multiple application containers

BJO February 2006
The majority of eye drops used in the United Kingdom contain preservatives and are bottled in plastic containers. Preservative free drops are used to avoid ocular irritation and allergies in certain individuals. The aim of this study was to investigate the incidence of microbial contamination of preservative free drops dispensed from multiusage containers.
Eye drop bottles were collected from patients attending the Tennent Institute of Ophthalmology outpatient and inpatient departments. The bottles were collected on day 3 (for inpatients) and day 7 (for outpatients) of use. The drops were inoculated onto different culture plates (chocolate agar, blood agar, fungal culture media, and enriched media) and the resulting microbial growth was identified using standard microbial identification techniques.
Results: 95 eye drop bottles were collected, containing a variety of 10 different eye drops. Significant bacterial growth was found in eight bottles. In total, seven different types of organism were identified from the eye drops. The organisms identified were Staphylococcus aureus, coagulase negative staphylococcus, Bacillus spp, Serattia spp, Klebsiella oxytoca, Enterobacter cloacae, and alpha streptococcus. Staph aureus was the commonest microbial organism.

Posted by aman at 12:20 AM | Comments (0)

Genetic research shows AMD most likely more than one disease

OSN BREAKING NEWS
Eugene de Juan, MD, discussed the confusing and ever-changing state of genetic research on AMD at Retina 2006, held in conjunction with Hawaiian Eye 2006.
Aside from known risk factors such as diet, smoking and systemic health, most estimates hold that roughly 50% of the causes of AMD have to do with genetics.
The first gene discovered to be associated with AMD, known as ABCA4, is also believed to cause Stargardt’s disease, along with retinitis pigmentosa and pattern dystrophy, Dr. de Juan said. This gene, however, is apparently not associated with vision loss in AMD.
Most researchers concur that the most important genetic finding regarding AMD has been the identification of complement factor H, which appears to cause AMD in 35% of people who test positive for the gene, he said.
Yet complement factor H is not associated with geographic atrophy, according to Dr. de Juan, meaning that “geographic atrophy is either a different disease, or maybe it’s not related to choroidal neovascularization,” he said.
The finding of proteins associated with AMD, including synaptopodin, a platelet-derived growth factor, supports the notion that there are “interacting genes,” Dr. de Juan said, “which may explain much of the variability of expression.”

Posted by aman at 12:13 AM | Comments (0)

PDT can be effective in non-AMD CNV

OSN BREAKING NEWS
Younger patients, patients with relatively good vision and patients with predominantly classic choroidal neovascularization can be candidates for photodynamic therapy, one physician said.
PDT probably works better than anti-VEGF drugs for [choroidal neovascularization in] non-age-related macular degeneration,” said Nancy M. Holekamp, MD, here at Retina 2006, held in conjunction with Hawaiian Eye 2006.
An improvement of greater than one line was seen in 40% of treated eyes vs. 13% of untreated eyes, she said. In addition, there was improvement of more than three lines in 12% of eyes.
The change in visual acuity at 2 years was in favor of the PDT-treated group. This group was more likely to have improved visual acuity through 2 years,” Dr. Holekamp said.

Posted by aman at 12:09 AM | Comments (0)

HyperCruise’ system reduces energy delivery

OSN BREAKING NEWS
A phacoemulsification system that combines technologies from several companies can allow surgeons to raise their vacuum levels, reduce energy delivery, increase overall safety and improve efficiency, according to one user.
Dr. Davis explained that the HyperCruise system combines the Bausch & Lomb Millennium Microsurgical System with venturi pump; the STAAR Surgical CruiseControl device; the Chop X1 phaco tip from MicroSurgical Technologies; and a Bausch & Lomb #D4600 Air Exchange Line.
She said any phaco tip can be used, and still the maximum vacuum setting can be set at 400 mm Hg. The system has broad applicability, she said, and is “married best with venturi,” but can also be used with a peristaltic pump.
Dr. Davis said that the STAAR CruiseControl device “prevents surge by increasing resistance and decreasing interior diameter,” which she said is beneficial during cataract surgery.
Using the Bausch & Lomb power module, she said, energy is conserved and heat is reduced. She uses a setting of 55 pulses per second at a 58% duty cycle.

Posted by aman at 12:04 AM | Comments (0)

January 21, 2006

Non-arteritic anterior ischaemic optic neuropathy and the treatment of erectile dysfunction

British Journal of Ophthalmology 2006;90:154-157
Methods: A retrospective matched case-control study was conducted. 38 cases of NAION in males were identified from an academic ophthalmology practice in Birmingham, Alabama, and matched (on age) to 38 controls without a history of NAION. Self reported information regarding past and current use of Viagra and/or Cialis was obtained via a telephone questionnaire from interviewers who were not blind to case status.

Results: Overall, males with NAION were no more likely to report a history of Viagra or Cialis use compared to similarly aged controls (odd ratio (OR) 1.75, 95% confidence interval (CI) 0.48 to 6.30 and OR 1.82, 95% CI 0.21 to 15.39). However, for those with a history of myocardial infarction, a statistically significant association was observed (OR 10.7, 95% CI 1.3 to 95.8). A similar association was observed for those with a history of hypertension though it lacked statistical significance (OR 6.9, 95% CI 0.8 to 63.6).

Conclusions: For men with a history of myocardial infarction or hypertension the use of Viagra or Cialis may increase the risk of NAION. Physicians prescribing these medications to patients with these conditions should warn them about the potential risk of NAION.

Posted by mriazi at 09:55 AM | Comments (0)

Ultrahigh resolution optical coherence tomography in non-exudative age related macular degeneration

British Journal of Ophthalmology 2006;90:191-197
Methods: A UHR-OCT ophthalmic imaging system, which utilises a femtosecond laser light source capable of 3 µm axial resolution, was employed to obtain retinal cross sectional images of patients with non-exudative AMD. Observational studies of the resulting retinal images were performed.

Results: 52 eyes of 42 patients with the clinical diagnosis of non-exudative AMD were imaged using the UHR-OCT system. 47 of the 52 (90%) eyes had the clinical diagnosis of drusen and/or retinal pigment epithelial (RPE) changes. In these patients, three patterns of drusen were apparent on UHR-OCT: (1) distinct RPE excrescences, (2) a saw toothed pattern of the RPE, and (3) nodular drusen. On UHR-OCT, three eyes (6%) with a clinical diagnosis of non-exudative AMD had evidence of fluid under the retina or RPE. Two of these three patients had findings suspicious for subclinical choroidal neovascularisation on UHR-OCT.

Conclusion: With the increased resolution of UHR-OCT compared to standard OCT, the involvement of the outer retinal layers are more clearly defined. UHR-OCT may allow for the detection of early exudative changes not visible clinically or by angiography.

Posted by mriazi at 09:44 AM | Comments (0)

Impaired retinal autoregulation in small retinal arterioles before and after focal laser treatment for diabetic maculopathy

British Journal of Ophthalmology 2006;90:198-201
Methods: In 17 diabetic patients the diameter response of arterioles after an increase in the arterial blood pressure induced by isometric exercise was studied using the retinal vessel analyser (RVA). In each patient a study arteriole supplying a focal area of macular oedema as well as a control arteriole supplying a retinal area without retinopathy lesions was selected, and the diameter response of these vessels was performed immediately before, and 1 hour and 3 months after focal laser photocoagulation of the focal oedema area.

Results: The diameter response was impaired in both study arterioles and control arterioles before focal laser photocoagulation. The treatment induced regression of the focal retinal oedema, but did not affect the diameter response in the arteriole supplying this area (p = 0.85).

Conclusion: Impairment of the diameter response in small arterioles from diabetic patients does not parallel the regional distribution of retinopathy lesions. Other factors than disturbed autoregulation are probably involved in generating flow disturbances and oedema in diabetic maculopathy.

Posted by mriazi at 09:38 AM | Comments (0)

Pregnant Mom’s Drinking May Affect Infant’s Vision

News in Review
A child doesn’t need to have outright fetal alcohol syndrome (FAS), and the mother does not have to be an alcoholic, for maternal alcohol use during pregnancy to reduce visual acuity in the infant, a study conducted in Cape Town, South Africa, by American researchers has concluded.

Furthermore, the visual acuity deficit was most significant in children of mothers who were 30 or older at the time of delivery.

“If they’re drinking four or more drinks at a time, their child is particularly at risk for these and other alcohol-related neurobehavioral problems,” Dr. Jacobson said.

In a prospective study published in The Journal of Pediatrics,¹ the researchers reported on 61 women who drank heavily during pregnancy, and 70 who drank little or no alcohol.

The babies were tested at 6.5 months of age using the Teller Acuity Card (TAC) test of resolution acuity. Normal acuity on TAC is 6.8 cycles per degree in infants this age, and the fifth percentile is < 3.38 cycles per degree.

Of the infants examined, 22 were diagnosed with FAS, and scored a mean of 2.69 cycles per degree. Whereas 27 percent of the infants with FAS scored below the fifth percentile, 9 percent of the infants without FAS scored that low. However, half of these low-scoring infants were born to mothers who reported drinking more than five drinks per occasion during pregnancy.

Posted by mriazi at 09:07 AM | Comments (0)

January 20, 2006

A Useful Augmented Lateral Tarsal Strip Tarsorrhaphy for Paralytic Ectropion

ophthalmology,Jan,2006
Patients with paralytic ectropion and lagophthalmos may experience keratitis and may pose a functional and aesthetic surgical challenge. Various methods are used to reduce the vertical palpebral aperture, including lateral tarsal strip (LTS) or a lateral tarsorrhaphy. We modified the LTS to differentially shorten and elevate the lower lid more than the upper: an augmented LTS tarsorrhaphy (aug-LTS-T).
Fourteen consecutive adult patients (15 eyelids) with chronic lagophthalmos and paralytic ectropion underwent aug-LTS-T. This consisted of a long strip (10–15 mm) that is attached to the outer temporal orbital rim, at a point higher than a conventional LTS. It included removal of a small part of the upper eyelid anterior lamella laterally to pass the long strip up high enough.Minimum follow-up was 6 months. There was a significant reduction in PA (P = 0.005) and lagophthalmos (P = 0.0002) with improvement of corneal signs (14 of 15 eyelids = 93%). Surgery was successful anatomically in 14 of 15 eyelids (93%) with low morbidity.
Conclusions:We describe the augmented LTS tarsorrhaphy and find it effective in the treatment of severe lower eyelid ectropion resulting from facial palsy.

Posted by afarahi at 12:33 PM | Comments (0)

Lateral Tarsal Strip and Everting Sutures for Involutional Entropion Can Be Performed by General Ophthalmologists

Ophthalmology,Jan,2006 (EyeNet)
Involutional entropion is a common eyelid malposition in the elderly caused by progressive attenuation of the lower lid soft tissue with horizontal and vertical laxity and enophthalmos.
Barnes et al. describe a solution involving a lateral tarsal strip and everting sutures (LTS+ES). In this approach, a standard lateral tarsal strip was created via a 10-millimeter lateral canthotomy incision and fashioned to an appropriate length to correct the horizontal lid laxity. A double-ended 5.0 nonabsorbable suture was placed through the strip. Four 6.0 Vicryl everting sutures were sited in the lateral two-thirds of the lower eyelid, and the lateral tarsal strip was secured inside the lateral orbital rim before tightening the everting sutures. The lateral canthotomy was closed in two layers.
Ophthalmic plastic surgeons and trainees performed this procedure, and 53 of 54 eyelids had a successful outcome with no recurrence by 18 months. The authors conclude LTS+ES is a good option for involutional entropion repair for the general ophthalmologist.

Posted by afarahi at 12:18 PM | Comments (0)

January 19, 2006

Auditory and Visual Toxicity During Deferoxamine Therapy in Transfusion-Dependent Patients.

Journal of Pediatric Hematology/Oncology. December 2005.

Deferoxamine is a chelating agent that has extended the life expectancy of patients with thalassemia. In the 1980s, many investigators reported otologic and visual toxicity caused by deferoxamine. In July 1999 and 2 years later, the authors performed audiologic and ophthalmologic assessments in 30 transfusion-dependent patients receiving deferoxamine therapy (40-50 mg/kg per dose, subcutaneously for 8-10 hours, 4-7 days per week). In 1999, six patients (20%) had deferoxamine-related hearing impairment (>25 dB), all at high frequencies. Because the authors believed the benefits of chelation therapy outweighed the risk of ototoxicity, the dose of deferoxamine was not reduced. Two years later, the hearing impairment had not progressed in any of the patients. There was no association between ototoxicity and ferritin level. No patients had abnormalities of visual acuity or funduscopy in either 1999 or 2001. Based on this experience, deferoxamine at doses lower than 50 mg/kg/d was safe for the eyes and slightly toxic to the ears. The ototoxicity probably relates to individual susceptibility. Regular monitoring of auditory function and close follow-up of abnormal findings are recommended. According to this limited experience, reducing the dose or withdrawing deferoxamine might not be necessary if the hearing loss is stable in the face of ferritin levels above 2,000 ng/mL. Because of the relatively small patient numbers, more data are needed to confirm these conclusions

Posted by afarahi at 12:38 PM | Comments (0)

Blepharokeratoconjunctivitis in Children

Arch Ophthalmol, December, 2005

In a retrospective case series review of 195 medical records revealed that blepharokeratoconjunctivitis was the most common single diagnosis at consultation, accounting for 15% of referrals. Of the 29 cases identified, there were 16 girls (55%) and 13 boys (45%). The mean age at consultation was 6 years (age range, 2-12 years). On initial ophthalmologic examination, 11 (38%) of 29 patients were taking full-strength steroids and 4 patients (14%) were taking oral erythromycin. Oral therapy, in the form of erythromycin (n = 21) and doxycycline (n = 1), was prescribed to most patients (22/29 [76%]). Therapy with topical steroids was tapered at the initial visit in all patients. Follow-up was available for 15 of 29 patients, with a mean follow-up of 5.4 months (range, 2-25 months). The condition of all patients showed clinical improvement. Recurrences were noted in 6 (40%) or 15 patients; all were successfully managed with low-potency steroid therapy.
Conclusions : Blepharokeratoconjunctivitis is a common reason for cornea referral in children. Oral erythromycin therapy is an effective treatment with a steroid-sparing effect. Recurrences are common and may be successfully managed with low-potency steroid therapy.

Posted by afarahi at 12:28 PM | Comments (0)

January 16, 2006

Multifocal Visual Evoked Potential a Sensitive, Specific Tool for Detecting Optic Neuritis

Ophthalmology
February’s issue
Multifocal visual evoked potentials (mVEP) is a method to diagnose optic pathway conditions by assessing visual evoked potentials as responses from multiple individual segments of the field of vision, allowing for objective information about amplitude to be combined with information on latency.

Fraser et al. conducted a cross-sectional study to determine if mVEP can detect evidence of optic neuritis (ON) and whether the results can differentiate between ON as a manifestation of multiple sclerosis (MS) and purely inflammatory ON.

The authors found that not only was mVEP a sensitive and specific tool for detecting optic neuritis, but there existed a significant difference in latency analysis findings between patient groups classified according to the McDonald MS criteria.

They conclude that if this latency pattern does reflect future clinical course, then the mVEP could provide a means of identifying those with a greater risk of future MS in the early post-acute stage of ON from those with white matter changes on MRI, thus helping physicians to determine optimal treatment strategies.

Posted by mriazi at 12:17 PM | Comments (0)

Medicare Data Show Uveitis in the Elderly More Prevalent Than Previously Thought

Ophthalmology
February’s issue
Uveitis in the elderly is more prevalent than previously thought, according to a Medicare cohort study by Reeves et al. The researchers studied data from a cohort of 21,644 Medicare beneficiaries drawn from the National Long-Term Care survey, a random sample of adults 65 years and older followed from 1991 through 1999.

The yearly uveitis incidence in this cohort averaged about 341 cases per 100,000. Anterior uveitis accounted for the majority of cases. The authors noted that the cohort experienced an almost 2 1/2-fold increase in uveitis prevalence, from 511 cases per 100,000 to 1,231 cases per 100,000 over the time period of the study, suggesting that the elderly can expect a marked increase in the burden of uveitis as the population ages.

Finally, this study demonstrated that Medicare claims data may represent a rich source of information, serving as a useful and cost-effective tool for monitoring uncommon diseases.

Posted by mriazi at 12:12 PM | Comments (0)

No Association Seen Between Apolipoprotein E Gene and Early Age-Related Maculopathy

Ophthalmology
February’s issue
The apolipoprotein E (APOE) gene has been shown to influence lipoprotein metabolism and is linked to neurodegenerative disorders such as Alzheimer’s disease. While an association between the APOE gene and age-related maculopathy (ARM) has been hypothesized, Wong et al. did not find evidence of a strong relationship in the Atherosclerosis Risk in Communities Study.

This population-based, cross-sectional study involved 10,139 middle-aged men and women of white and African-American ethnicity living in Forsyth County, N.C., Jackson, Miss., the suburbs of Minneapolis, Minn., and Washington County, Md. The researchers found no evidence of a strong association between APOE and early ARM, even after controlling for age, gender, race and cigarette smoking.

They caution that the study population was relatively young and the prevalence of early ARM was only 5 percent. Consequently, they cannot exclude the possibility of a weaker association or that APOE may only influence the development of late ARM in older populations.

Posted by mriazi at 12:06 PM | Comments (0)

January 14, 2006

Vitreous hemorrhage drug filed for regulatory approval in EU

OSN BREAKING NEWS
An ovine hyaluronidase treatment for vitreous hemorrhage will be reviewed by the European Medicines Evaluation Agency for regulatory approval, the drug’s marketer said in a press release.
The filing was based upon existing clinical trial data, including results from two randomized, double-masked, placebo-controlled international phase 3 trials. The data showed a statistically significant reduction in vitreous hemorrhage density as early as 1 month that persisted through 3 months after a single intravitreous injection when compared to a single injection of saline.

Posted by aman at 10:26 PM | Comments (0)

Effect of Perioperative Glycemic Control in Progression of Diabetic Retinopathy and Maculopathy

ARCHIVES Vol. 124 No. 1, January 2006
To evaluate the contribution of perioperative glycemic control to progression of diabetic retinopathy and maculopathy.
Methods Postoperative progression of diabetic retinopathy and maculopathy were compared in 87 patients with type 2 diabetes mellitus who underwent monocular phacoemulsification cataract surgery performed by a single surgeon. Twenty-seven patients had had poor glycemic control preoperatively and underwent rapid preoperative glycemic correction; 30 patients had poor control preoperatively that was not corrected postoperatively; and 30 patients had good preoperative glycemic control. The grade of diabetic retinopathy and maculopathy in the operated-on eye and the fellow eye was assessed preoperatively and for 12 months
postoperatively.
Results There were no significant differences in the progression rate of diabetic retinopathy among the 3 groups (P = .27). However, the progression rate of diabetic maculopathy was significantly higher in the group that underwent rapid control than in the other 2 groups (P = .02). Patients with moderate to severe nonproliferative diabetic retinopathy preoperatively in the rapid control group had significantly higher progression rates of diabetic retinopathy and maculopathy (P = .002 and .008, respectively).
Conclusions Rapid preoperative glycemic control should be avoided in patients with moderate to severe nonproliferative diabetic retinopathy because it may increase the risk of postoperative progression of retinopathy and maculopathy.

Posted by aman at 10:18 PM | Comments (0)

Outcome of Eyes Developing Retinal Detachment During the Early Treatment for Retinopathy of Prematurity Study (ETROP)

ARCHIVES Vol. 124 No. 1, January 2006
Method Infants in the ETROP Study with bilateral high-risk prethreshold ROP had 1 eye randomized to early treatment, with the fellow eye managed conventionally. In infants with asymmetric disease, the eye with high-risk prethreshold ROP was randomized to early treatment or conventional management. When a retinal detachment was detected, observation or vitreoretinal surgery (ie, scleral buckling and/or vitrectomy) was provided at the discretion of the individual investigator. At 9 months corrected age, retinal examinations were performed and visual acuities were assessed by masked testers using grating acuity.
Conclusions In the ETROP Study, the outcome of retinal detachment owing to ROP was generally poor. Vitreoretinal surgery for retinal detachment was associated with macular attachment in 16 of 48 eyes. Normal acuity was maintained after surgical repair of stage 4A retinal detachment in 5 (21%) of 24 eyes. Vitreoretinal surgery for stage 5 disease was associated with some structural successes but poor functional outcomes.

Posted by aman at 10:11 PM | Comments (0)

Two diabetes drugs linked to worsening diabetic eye complications

Drug News
The FDA and drug company GlaxoSmithKline are alerting doctors about reports of new or worsening macular edema and blurred vision in patients with diabetes taking the drugs Avandia or Avandamet. A GlaxoSmithKline letter sent to doctors makes these points: The reports are "very rare." Most patients also reported swelling in their legs and feet at the same time. In some cases the macula edema stopped or improved when patients stopped taking the drugs. In one case, macula edema stopped when the drug's dose was reduced.

Posted by kjalali at 07:34 PM | Comments (0)

Macugen appears to reduce retinal neovascularization in patients with diabetes

Ophthalmology, Jaunaury 2006
This retrospective analysis of a randomized clinical trial included patients with a best-corrected visual acuity letter score between 68 and 25 (approximate Snellen equivalent between 20/50 and 20/320) who received a sham injection or intravitreal pegaptanib (0.3 mg, 1 mg, 3 mg) administered at study entry and at 6 and 12 weeks, with additional injections and/or focal photocoagulation as needed during the ensuing 18 weeks, up to a maximum of six pegaptanib/sham therapies. Sixty-two percent of the patients in the pegaptanib treatment group (including the one receiving panretinal photocoagulation) showed either regression of neovascularization on fundus photographs or regression or absence of fluorescein leakage from neovascularization (or both) at 36 weeks. The authors conclude that these findings suggest pegaptanib has a direct effect on retinal neovascularization in patients with diabetes mellitus.

Posted by kjalali at 07:31 PM | Comments (0)

Patients with moderate to severe obstructive sleep apnea have a higher incidence of visual field defect

Eye, January 2006
This case control study compared 41 ethnic Chinese patients diagnosed with moderate to severe obstructive sleep apnea and 35 age-matched subjects without the condition. In the sleep apnea group, visual field indices were significantly subnormal and the incidence of suspicious glaucomatous disc changes was four times higher than that of the control arm. None of the studied patients suffered from any form of anterior segment complications.

Posted by kjalali at 07:25 PM | Comments (0)

Topical antibiotics and microbial resistance: something to think about

Specialty News and Views: Cornea/External Disease - November 2005
Specialty News & Views authors discuss a recent study on the management of trachoma in Nepal that includes a surprising finding: annual mass treatment with topical tetracycline ointment increased the tetracycline resistance of S. pneumoniae. Specialty News & Views authors conclude that ophthalmologists may be contributing to, and changing, the antibiotic resistance pattern of nasopharyngeal organisms with the use of topical antibiotics. This may have little consequence in most patients, but as more individuals are immunosuppressed with more potent drugs, ophthalmologists should be wary of adding to antimicrobial resistance and the spread of these resistant organisms. The study authors don’t advocate changes to antibiotic treatment at this time, but the Specialty News & Views authors say their work “should give us all a moment’s pause.”

Posted by mriazi at 10:04 AM | Comments (0)

Recommendations on preoperative fasting for pediatric patients

Specialty News and Views: Pediatric/Strabismus - January 2006
The American Academy of Pediatrics has published pediatric preoperative fasting recommendations to reduce the risk of pulmonary aspiration. Though the guidelines are not new, their importance is underscored by a recent discussion in American Academy of Pediatrics News. The simple rule to remember: two hours for clear liquids, four hours for breast milk and six hours for everything else, including formula. The task force suggests an eight-hour fast following meals that included substantial quantities of fried or fatty foods or meats, all of which can prolong gastric emptying

Posted by mriazi at 09:59 AM | Comments (0)

Evaluation of Plasma Homocysteine and Risk of Age-Related Macular Degeneration

AJO January 2006
Fasting plasma homocysteine levels were measured at two centers in 934 individuals who were participating in an ancillary study of the Age-Related Eye Disease Study. There were 547 cases and 387 control subjects, who were determined by fundus photography. Conditional logistic regression analyses were conducted to assess the association of homocysteine with AMD.

Results
Median values of homocysteine were higher among advanced AMD cases (9.51 mmol/l) compared with persons with no AMD (8.81 mmol/l; P = .01). Values of >12 mmol/l vs ≤12 mmol/l were also associated with an increased risk of AMD (P = .023), when controlled for other covariates.

Conclusion
Results are consistent with a possible small, independent association between higher homocysteine levels and AMD. Homocysteine may be a modifiable risk factor for AMD.

Posted by mriazi at 09:35 AM | Comments (0)

Consider screening pediatric uveitis patients for TINU

Specialty News and Views: Uveitis - December 2005
A recent study of 12 patients with tubulointerstitial nephritis and uveitis syndrome (TINU) suggests clinicians should consider screening cases of pediatric uveitis for TIN even with no history or symptoms of nephritis. Given the limited available literature on TINU, Specialty News & Views authors say this is a significant contribution. Uveitis may precede nephritis by weeks to months. Creatinine and urinalysis may not be sufficient to diagnose nephritis, and elevated urine microglobulin may be a better test. In children with chronic iridocyclitis who are negative for juvenile idiopathic or rheumatoid arthritis, a urine beta-microglobulin test should be considered.

Posted by mriazi at 09:24 AM | Comments (0)

TASS outbreak linked to autoclave steam

Specialty News and Views: Retina/Vitreous - December 2005James Bolling of the Mayo Clinic in Jacksonville, Fla., reported on a recent outbreak in his clinic similar to epidemic endophthalmitis in which 38 percent of patients undergoing cataract surgery developed abnormal inflammation within 24 hours after cataract surgery. The cases were evaluated for potential causes of toxic anterior segment syndrome (TASS) and upon extensive investigation involving the U.S. Centers for Disease Control and Prevention, it was revealed that the autoclave steam condensate contained high concentrations of copper, zinc, sulfates, nickel and silica due to infrequent cleaning of the steam generator. Bolling and his colleagues recommend set standards for processing instruments for eye surgery.

Posted by mriazi at 09:18 AM | Comments (0)

Two diabetes drugs linked to worsening diabetic eye complications

INDUSTRY NEWS
The FDA and drug company GlaxoSmithKline are alerting doctors about reports of new or worsening macular edema and blurred vision in patients with diabetes taking the drugs Avandia or Avandamet. A GlaxoSmithKline letter sent to doctors makes these points: The reports are "very rare." Most patients also reported swelling in their legs and feet at the same time. In some cases the macula edema stopped or improved when patients stopped taking the drugs. In one case, macula edema stopped when the drug's dose was reduced.

Posted by mriazi at 09:10 AM | Comments (0)

January 13, 2006

Endoscopic Orbital Decompression for Graves' Ophthalmopathy

American Journal of Rhinology, November-December 2005,

Graves' ophthalmopathy generates a volume excess for the orbital cavity, which may produce proptosis, pain, exposure keratitis, diplopia, and optic neuropathy. Endoscopic orbital decompression expands the orbital cavity into the ethmoid cavity and medial maxillary sinus. This retrospective study documents the outcomes after endoscopic orbital decompression for patients with Graves' ophthalmopathy. Between July 1989 and April 2003, 62 patients were referred for endoscopic orbital decompression (often unilateral).
Seventy percent were women; the average age of the study group was 49 years. Preoperatively, 63% of the patients had diplopia and optic neuropathy was noted in 27%. Two patients had a cerebrospinal fluid leak identified and managed during the decompression. No postoperative leaks occurred. Twenty-five percent of patients did not require eye muscle surgery. The average reduction in proptosis was 2.5 mm.
Conclusion: This data supports the safety, efficiency, and efficacy of endoscopic orbital decompression for unilateral and bilateral Graves' ophthalmopathy. Eye muscle surgery frequently will be required to manage diplopia after decompression.

Posted by afarahi at 10:39 PM | Comments (0)

January 11, 2006

Successful Treatment of Idiopathic Orbital Inflammation With Mycophenolate Mofetil

AJO,Nov,2005
We reviewed the records of five patients with idiopathic orbital inflammation(IOI )who were treated with mycophenolate mofetil. The indications for use included recurrent inflammation after other therapies (four patients) and to avoid corticosteroid-induced blood sugar elevation in poorly controlled diabetes mellitus (one patient). Treated patients were followed for a median of 8.5 months (range, 4–30 months) after mycophenolate mofetil therapy was begun. Mycophenolate mofetil therapy was discontinued in one patient because of nausea. Each of the remaining four patients experienced complete resolution of orbital inflammation. Of these, only one patient remains on prednisone, but at a significantly reduced dose (1 mg/d).
Conclusion:Mycophenolate mofetil therapy resulted in the resolution of inflammation in patients with refractory or corticosteroid-dependent IOI and was used successfully for a first episode of IOI in a patient for whom corticosteroids were contraindicated.

Posted by afarahi at 12:09 PM | Comments (0)

January 10, 2006

Study: Twice-daily dosing of dexamethasone effective after strabismus surgery in children

OCULAR SURGERY NEWS EUROPE/ASIA-PACIFIC EDITION January 2006
Twice-daily dosing of dexamethasone after strabismus surgery in children was found to be as effective in controlling inflammation as dosing four times daily while inducing less IOP increase, according to a group of researchers.
Prof. Dennis S.C. Lam, FRCS, FRCOphth, and colleagues at the Chinese University of Hong Kong randomly assigned 137 children undergoing bilateral strabismus surgery to receive topical 0.1% dexamethasone eye drops either four times daily or twice daily for 4 weeks.
IOP and anti-inflammatory responses were monitored for 8 weeks.
A lower dosage of corticosteroids was shown to be associated with a lesser degree of IOP rise in the present study,” the researchers reported in Clinical and Experimental Ophthalmology. “The anti-inflammatory responses, assessed by subjective and objective inflammatory scores, failed to show a significant difference between the two groups. Therefore, a lower frequency schedule of topical 0.1% dexamethasone after strabismus surgery may be considered.”

Posted by aman at 12:41 AM | Comments (0)

Etanercept suppressed signs of Graves’ ophthalmopathy in trial

OSN BREAKING NEWS
Etanercept, a drug used in the treatment of rheumatoid arthritis, may be beneficial in the treatment of Graves’ ophthalmopathy, a study suggests.
Willem A. van den Bosch, MD, and colleagues from the Rotterdam Eye Hospital treated 10 consecutive patients with recent-onset, active, mildly to moderately severe Graves’ ophthalmopathy using the anti-tumor-necrosis-factor drug. Patients received subcutaneous injections of 25 mg of etanercept twice weekly for 12 weeks. Mean patient age was 50 years at baseline, and average duration of Graves’ ophthalmopathy was 4 months.
After treatment, 60% of patients reported moderate to marked improvement. No serious adverse events or side effects were reported during a mean 18 months of follow-up.
This study strongly suggests that etanercept may suppress the clinical signs of Graves’ opthalmopathy, but randomized controlled trials are needed to further evaluate the effect of antitumor necrosis factor treatment and to compare its side effects with those of corticosteroids,

Posted by aman at 12:36 AM | Comments (0)

Perceptual learning may aid in amblyopia treatment

OSN BREAKING NEWS
The visual system of the adult with amblyopia may still retain some plasticity, and perceptual learning may be a valuable clinical tool for treating pediatric and adult amblyopia, a recent study suggests.
Researchers in China and the United States evaluated the effects of perceptual learning on contrast sensitivity and visual acuity in 23 anisometropic amblyopes whose mean age was 19 years.
The subjects were divided into three groups. One group received training in grating detection in the amblyopic eye close to their pre-training spatial frequency cutoff. A second group underwent a training regimen of repeated contrast-sensitivity function measurements in the amblyopic eye. A third group received no training in either eye.
We found that training substantially improved visual acuity and contrast sensitivity functions in the amblyopic eyes of all the observes in groups 1 and 2, although no significant performance improvements was observed in group 3,” said the authors, Yifeng Zhou and colleagues. In several subjects, improvements in visual acuity after training had about 90% retention for almost 1 year, the authors said.

Posted by aman at 12:31 AM | Comments (0)

January 07, 2006

Using different imaging methods interchangeably may lead to inaccurate glaucoma diagnoses

Ophthalmology, December 2005
The optic disc topography measurements of 42 randomly chosen subjects (42 eyes) were obtained with three imaging methods: the Heidelberg Retina Tomograph (HRT II), Retinal Thickness Analyzer (RTA) and Optical Coherence Tomograph (StratusOCT). Researchers observed a moderate to high correlation in optic disc topography measurements among the different instruments; however, the analysis of agreement indicated important discrepancies among instruments. The authors conclude that these instruments should not be used interchangeably to obtain optic disc measurements for glaucoma diagnosis.

Posted by kjalali at 05:47 PM | Comments (0)

Preoperative counseling on possible visual sensations during phacoemulsification can reduce patient fear

JCRS October 2005
This prospective, multi-center clinical trial randomized 219 patients having elective cataract surgery under topical anesthesia (168 Chinese, 13 Malays, seven Indians and 31 British patients) into two groups: one got additional counseling on the potential visual experience during surgery and one did not. The mean fear score was 0.3 in the group receiving additional counseling and 0.9 in the group that did not (P = .036). The fear reduction was significant (P = .002) even after controlling for sex, age and whether it was a first or second cataract surgery.

Posted by kjalali at 05:44 PM | Comments (0)

First all-laser “top hat” cornea transplant

The Cornea Research Foundation of America
The Corneal Research Foundation of America reports that Francis W. Price, Jr., MD, has used the IntraLase FS laser to precisely cut a graft designed to provide faster and stronger healing compared with traditional transplant methods. The high-speed femtosecond laser allows the surgeon to produce “complex contours and custom designs” for each transplant patient, Price said. It’s called the top-hat procedure because the donor button is shaped with a lip of tissue, like the brim of a top hat. The recipient bed is also shaped by the laser to accommodate the lip, which helps hold the graft in place.

Posted by kjalali at 05:37 PM | Comments (0)

Ophthalmologists may be contributing to antibiotic resistance patterns by routinely prescribing topical antibiotics

BJO 2005
There is a recent study on the management of trachoma in Nepal that includes a surprising finding: annual mass treatment with topical tetracycline ointment increased the tetracycline resistance of S. pneumoniae. So ophthalmologists may be contributing to, and changing, the antibiotic resistance pattern of nasopharyngeal organisms with the use of topical antibiotics. This may have little consequence in most patients, but as more individuals are immunosuppressed with more potent drugs, ophthalmologists should be wary of adding to antimicrobial resistance and the spread of these resistant organisms.

Posted by kjalali at 05:29 PM | Comments (0)

Posterior sub-tenon triamcinolone for refractory diabetic macular edema: A randomized clinical trial

Eur J Ophthalmol 2005
M. Entezari1, H. Ahmadieh2, M.H. Dehghan2, A. Ramezani1, N. Bassirnia1, A. Anissian3

In a double-masked placebo-controlled clinical trial, 64 eyes were randomly assigned to two groups. The treatment group (32 eyes) received 40 mg posterior sub-tenon injection of TA and the placebo group (32 eyes) received subconjunctival injection of a placebo. The injections were repeated after 2 months in both groups. Complete ophthalmologic examination, fluorescein angiography, and OCT were performed before intervention and after 4 months. Quantitative measurement of angiographic variables such as the amount of hard exudates (HE), size of foveal avascular zone (FAZ), and leakage severity was performed by computer, using Photoshop software.
CONCLUSIONS. Two injections of posterior sub-tenon TA had no therapeutic effect on refractory DME.

Posted by aman at 01:02 AM | Comments (0)

Intravitreal triamcinolone acetonide for treatment of central retinal vein occlusion

Eur J Ophthalmol 2005
This prospective comparative non-randomized clinical interventional study included 32 patients (33 eyes) with central retinal vein occlusion. The study group (12 patients; 13 eyes) received an intravitreal injection of about 20 mg of triamcinolone acetonide. The control group (20 patients) did not receive any treatment. Mean follow-up was 10.1±8.6 months in the study group and 6.0±5.2 months in the control group.
RESULTS. In the study group, mean visual acuity increased significantly (p=0.018) from 0.11±0.11 preoperatively to a best visual acuity during follow-up of 0.18±0.15. An improvement in visual acuity by at least 2 Snellen lines and 3 Snellen lines, respectively, was found for 8 (62%) eyes and 5 (38) eyes. Visual acuity measurements determined 1 month (p=0.038) and 3 months (p=0.046) after the injection were significantly higher than the baseline values. Increase in visual acuity was higher in the non-ischemic subgroup than in the ischemic subgroup. In the control group, baseline visual acuity and best visual acuity during the followup did not vary significantly (p=0.33). Visual acuity decreased significantly (p=0.007) towards the end of the follow-up. Comparing study group and control group, gain in visual acuity was significantly (p=0.01) higher in the study group. In the study group, intraocular pressure increased significantly (p=0.018) from 14.4±3.9 mmHg to a mean maximal value of 21.6±9.2 mmHg (range, 10–44 mmHg), and re-decreased (p=0.012) towards the end of follow-up to 15.3±5.1 mmHg (range, 10–21 mmHg).

Posted by aman at 12:51 AM | Comments (0)

Risk factors of massive suprachoroidal hemorrhage during extracapsular cataract extraction surgery

Eur J Ophthalmol 2005
The study was conducted on 6639 consecutive cataract extractions performed between 1994 and 2002. All of the procedures were carried out using traditional nucleus expression methods. The study cases comprised 19 patients who developed intraoperative MSCH. The remaining 6620 patients served as the control group. Baseline systemic and ocular characteristics, as well as intraoperative factors, were analyzed. Categorical variables were analyzed using the chi-square test and the Fisher exact test.
RESULTS. The incidence of MSCH during cataract surgery was 0.28%. Highly significant risk factors included high myopia, glaucoma, and diabetes (p<0.01). Atherosclerotic vascular diseases and/or hypertension were less significantly related to the condition (p<0.05). There was no significant relationship between MSCH formation and age, sex, side of the cataract, history of ocular trauma, or inflammation. The incidence of MSCH did not differ between patients operated on with extracapsular or intracapsular cataract extraction.

Posted by aman at 12:46 AM | Comments (0)

The triple classification of dry eye for practical clinical use

Eur J Ophthalmol 2005PURPOSE. “Dry Eye is a condition produced by the inadequate interrelation between lacrimal film and ocular surface epithelium, and is caused by quantitative and qualitative deficits in one or both of them. It can be produced by one or combined etiologic causes, affecting one or several of the secretions of the glands serving the ocular surface, and producing secondary manifestations of different grades of severity”. Clinicians need a practical classification to face diagnosis, prognosis and treatment. Dry eyes have many etiologies and pathogenesis, different affectation of the various dacryoglands and ocular surface epithelium, and diverse grades of severity. The specialists in xero-dacryology must know these three parameters to evaluate any case of dry eye, and to establish an adequate treatment.
CONCLUSIONS. The following classification has been established: First, a classification of the etio-pathogenesis, distributed in ten groups: age-related, hormonal, pharmacologic, immunopathic, hyponutritional, dysgenic, infectious/inflammatory, traumatic, neurologic and tantalic. Second, a classification of the affected glands and tissues, which under the acronym of ALMEN includes the Aqueo-serousdeficient, Lipodeficient, Mucindeficient and Epitheliopatic dry eyes, and the Non dacryological affected exocrine glands (saliva, nasal secretion, tracheo-pharyngeal secretion, etc). And thirdly, a classification of severity, in three grades: Grade 1 or mild (symptoms without slitlamp signs), grade 2 or moderate (symptoms with reversible signs), and grade 3 or severe (symptoms with permanent signs).

Posted by aman at 12:36 AM | Comments (0)

The effect of hyperopic laser in situ keratomileusis on refractive accommodative esotropia

Eur J Ophthalmol 2005
A. Farahi1, H. Hashemi2

1Noor Vision Correction Center, Tehran - Iran
2Noor Vision Correction Center and Farabi Eye Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran - Iran
ABSTRACT
PURPOSE. To evaluate the efficacy of laser in situ keratomileusis (LASIK) for discarding spectacles and simultaneously correcting ocular alignment in patients with refractive accommodative esotropia.
METHODS. LASIK was performed on 20 eyes of 10 patients (mean age, 24.3 years; range, 11 to 43 years) using a Technolas 217C excimer laser. The target refraction was emmetropia. Visual acuity (uncorrected and best-corrected), refractive error, and ocular alignment were recorded before and after LASIK. Minimum follow-up was 12 months.
RESULTS. The mean preoperative uncorrected and corrected angle of deviation was 37.1 prism diopters (PD) (range, 17 to 80; standard deviation (SD), 19.8)) and 14.74 PD (range, 0 to 50; SD, 12.9) of esotropia, respectively, which changed to 7.2 PD (range, 0 to 50; SD, 15.78) without correction postoperatively (p=0.005). Of 20 eyes, 15% lost one line of best-corrected visual acuity, 10% gained two lines, and 75% showed no change.
CONCLUSIONS. LASIK could be considered an alternative treatment for patients with refractive accommodative esotropia with intolerance to glasses and contact lenses.

Posted by aman at 12:20 AM | Comments (0)

January 06, 2006

Results of LASIK to correct hyperopia after RK measured

EYEWORLD January 2006
LASIK is a safe, effective, and predictable treatment for the correction of consecutive hyperopia after RK, a new study suggests.
Deniz Oral, M.D., department of ophthalmology, The University of Texas Southwestern Medical Center at Dallas, and colleagues, analyzed 38 eyes of 25 patients treated with LASIK after secondary hyperopia following RK. The study was published in the August 2005 issue of the Journal of Cataract & Refractive Surgery.
All eyes studied had RK six to 21 years prior to LASIK surgery. While original RK surgery reports were only available for two eyes, researchers learned from taking patient histories that five (13%) had enhancement RK surgery following the initial RK procedure. Nine eyes also had one to four astigmatic keratotomy incisions.
LASIK procedures were performed using the Star S2, Star S3, and Star S4 lasers (VISX, now AMO, Santa Ana, Calif.). The LADARVision 4000 (Alcon, Fort Worth, Texas) also was used. Eyes were treated sometime from November 1999 to March 2003 to correct secondary hyperopia.
Pre-op mean uncorrected visual acuity (UCVA) was 0.56 (logMAR), which falls between 20/70 and 20/80. After LASIK, UCVA improved to 0.15 (logMAR) at six months (which falls between 20/25 and 20/30) and to 0.10 (logMAR), which is tantamount to 20/25, by the last visit.
More specifically, six eyes (27%) achieved 20/20 or better at six months. Nineteen eyes (86%) achieved 20/40 or better by six months. By the last visit, 10 eyes (40%) achieved 20/20 or better and 24 (96%) achieved 20/40 or better.
Researchers also analyzed refractive stability of 11 eyes that had data for all post-op visits. They found an average hyperopic shift between one and 12 months to be 0.12 D.
Complications
By the last visit, no eye lost more than two lines of best spectacle-corrected visual acuity (BSCVA). Two eyes (8%) lost two lines while six eyes (24%) lost a single line of BSCVA, the researchers said.
However, at the six-month period, one eye did have a transient loss of three lines of BSCVA, the researchers said.
“This is a transient finding without detectable problems and the patient’s BSCVA increased to the pre-operative level at the next follow-up visit,” Dr. Oral wrote in the study.
Other complications included visually non-significant interface haze formation, the researchers reported. This occurred in two eyes (5%). Epithelial cyst formation also occurred in RK incisions in three eyes (8%), they said. Epithelial ingrowth was caused in three eyes (8%), and one flap (3%) experienced a buttonhole.
“Epithelial ingrowth was stable and did not necessitate intervention in two eyes, whereas one eye needed flap lift and curative debridement for active ingrowth,” Dr. Oral observed. “The eye had retreatment for enhancement 30 months after the initial LASIK procedure.”
The case that experienced a buttonhole ultimately resulted in 20/30 vision after ablation 25 months post-op. The patient experienced a two-line decrease compared to pre-op levels.

Posted by aman at 11:28 PM | Comments (0)

Ciliary Body Edema after Scleral Buckling Surgery for Rhegmatogenous Retinal Detachment

OPHTHALMOLOGY January 2006
Choroidal detachment and anterior chamber (AC) shallowing develop in some cases after scleral buckling surgery for rhegmatogenous retinal detachment (RD). Postoperative angle-closure glaucoma has been reported to occur in 4% of cases. It is supposed that compression by the local scleral buckling induces ciliary body edema and angle narrowing. This study aimed to evaluate quantitatively the time course of changes in ciliary body thickness and AC depth (ACD) before and after the scleral buckling procedure using ultrasound biomicroscopy.
Prospective consecutive case series.
Forty-six eyes of 44 patients (43.7±18.1 years old [mean ± standard deviation]) undergoing rhegmatogenous RD surgery.
Ciliary body thickness and ACD were measured before and 3, 7, 14, and 28 days after the procedure. Ultrasound biomicroscopy was used to evaluate ACD and ciliary body thickness.
Conclusions
Even without apparent choroidal detachment and a shallow AC, subclinical ciliary edema existed in all directions of all eyes for at least 1 month after the scleral buckling procedure. The ciliary body in the direction of scleral buckling showed greater edema than the other areas. Eyes treated with the encircling band showed greater ciliary edema than those treated with segmental buckling alone.

Posted by aman at 11:20 PM | Comments (0)

Changes in Retinal Neovascularization after Pegaptanib (Macugen) Therapy in Diabetic Individuals

OPHTHALMOLOGY January 2006
Individuals with retinal neovascularization identified from a multicenter, randomized, controlled trial evaluating pegaptanib for treatment of diabetic macular edema, with a best-corrected visual acuity letter score between 68 and 25 (approximate Snellen equivalent between 20/50 and 20/320) and receiving a sham injection or intravitreal pegaptanib (0.3 mg, 1 mg, 3 mg) administered at study entry, week 6, and week 12, with additional injections and/or focal photocoagulation as needed during the ensuing 18 weeks, up to a maximum of 6 pegaptanib/sham therapies, were evaluated. Scatter panretinal photocoagulation before study enrollment was permitted, but not within 6 months of randomization and study entry. Changes in retinal neovascularization were assessed on fundus photographs and fluorescein angiograms graded at a reading center in a masked fashion.
Results
Of 172 participants, 19 had retinal neovascularization in the study eye at baseline. Excluding 1 who had scatter photocoagulation 13 days before randomization and 2 with no follow-up photographs, 1 of the remaining 16 subjects had panretinal photocoagulation during study follow-up. Of these 16 subjects, 8 of 13 (62%) in a pegaptanib treatment group (including the one receiving panretinal photocoagulation), 0 of 3 in the sham group, and 0 of 4 fellow (nonstudy) eyes showed either regression of neovascularization on fundus photographs or regression or absence of fluorescein leakage from neovascularization (or both) at 36 weeks. In 3 of 8 with regression, neovascularization progressed at week 52 after cessation of pegaptanib at week 30.
Conclusions
Most subjects with retinal neovascularization at baseline assigned to pegaptanib showed regression of neovascularization by week 36. These findings suggest a direct effect of pegaptanib upon retinal neovascularization in patients with diabetes mellitus.

Posted by aman at 11:15 PM | Comments (0)

Smoking, Alcohol Intake, Estrogen Use, and Age-related Macular Degeneration in Latinos: The Los Angeles Latino Eye Study

AJO 2006
To assess the association between smoking, alcohol intake, estrogen use, and both early age-related macular degeneration (AMD) (soft indistinct drusen, retinal pigment abnormalities) and advanced AMD (exudative AMD, geographic atrophy) in the Latino community, complete ophthalmic examination included stereoscopic macular photographs graded with a modified Wisconsin Age-related Maculopathy Grading System. A history of smoking, alcohol intake, and exogenous estrogen use was obtained by interview. Logistic regression was performed, and odds ratios (OR) were calculated with each AMD lesion as a dependent variable. There were 5875 participants (92.4%) with gradable photographs. Having ever smoked was associated with a higher risk of having advanced AMD (OR, 2.4). Heavy consumption of alcohol (>5 drinks per session) was significantly associated with a greater risk of having exudative AMD (OR, 5.8) and geographic atrophy (OR, 12.7) Beer drinking was associated with a higher risk of having advanced AMD (OR, 2.9), whereas wine drinking appeared to be protective for increased retinal pigment (OR, 0.7). Exogenous estrogen use also appeared to be protective from soft indistinct drusen (OR, 0.5) and increased retinal pigment (OR, 0.6), but power was limited in the assessment of its association with advanced AMD. Smoking and heavy alcohol consumption, particularly beer, was associated with a greater risk of having advanced AMD; exogenous estrogen use appeared to have a weak protective effect in Latino participants. Similar modifiable risk factors have been identified previously in non-Hispanic white patients, which suggests that common pathogenic mechanisms may be associated with AMD in persons of different ethnicities.

Posted by kjalali at 10:34 PM | Comments (0)

Role of Silicon Contamination on Calcification of Hydrophilic Acrylic Intraocular Lenses

AJO 2006
To verify the presence of the element silicon on hydrophilic acrylic intraocular lenses (IOLs) explanted because of calcification, twenty explanted IOLs with surface deposits (MemoryLens), and 20 with deposits mostly within their optic substance (SC60B-OUV and Aqua-Sense; 10 each) were used. After gross, microscopic, and histochemical analyses to confirm the presence of deposits, the lenses underwent scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDS) for elemental composition, on the external surface of MemoryLens IOLs, and on the surface and internal substance of SC60B-OUV and Aqua-Sense IOLs. The weight percentage of the element silicon was obtained at the level of deposits, and at adjacent deposit-free areas in all lenses. Scanning electron microscopy (SEM) coupled with EDS confirmed that the composition of the deposits was calcium/phosphate in all cases. The element silicon was found in all 40 lenses, on all areas analyzed. The silicon weight percentage was higher at the level of the deposits. The presence of aluminum on five MemoryLens IOLs, and in most of the SC60B-OUV and Aqua-Sense lenses might be related to scattering from the aluminum mounting stubs used for surface analyses. Silicone compounds have been implicated in the calcification of another hydrophilic acrylic design (Hydroview). They may also have a role in the calcification of other hydrophilic acrylic IOLs. Further investigation on the relationship between the presence of the element silicon and the silicone compounds found on calcified hydrophilic acrylic lenses is necessary.

Posted by kjalali at 10:30 PM | Comments (0)

Retinal Blood Flow and Macular Edema After Radial Optic Neurotomy for Central Retinal Vein Occlusion

AJO 2006
To determine the effect of radial optic neurotomy (RON) on retinal blood flow (RBF) and macular edema in eyes with a central retinal vein occlusion, seven eyes of seven patients with central retinal vein occlusion underwent RON and vitrectomy and were followed for at least 6 months. The RBF was calculated from dye dilution curves of video fluorescein angiograms. The foveal thickness was determined by optical coherence tomography. Neither RON nor chorioretinal anastomoses improved the RBF but macular edema was improved. These findings suggest that removal of the vitreous could reduce macular edema as in diabetic macular edema. However, we cannot exclude the possibility that the changes represent the natural course of this disease.

Posted by kjalali at 10:24 PM | Comments (0)

Complications and Visual Outcome of LASIK Performed by Anterior Segment Fellows vs Experienced Faculty Supervisors

AJO 2006
To determine the complication rates and visual outcome of laser-assisted in situ keratomileusis (LASIK) that is performed by anterior segment fellows and to compare their results with the results of their experienced faculty supervisors, chart review of the initial 50 LASIK procedures that were performed by each of 10 anterior segment fellows and the first 50 inclusion criteria-matched, contemporaneously performed cases of four faculty members at the King Khaled Eye Specialist Hospital between March and December 2003. There were no statistically significant differences between fellow and faculty cases with respect to complication rates and final visual outcomes. The fellows were significantly more likely to experience microkeratome-related flap complications during their first 25 cases, compared with their second 25 cases (4.8% vs 1.2%; P = .03). Fellows were significantly more likely to perform enhancements (8.0% vs 2.0%; P = .0002), after which the eyes in their group were more likely to be within 1 diopter of the intended refractive target than those in the faculty group (96.0% vs 91.0%; P = .01). Although not statistically significant, eyes in the fellow group were four-fold (2.0% vs 0.5%) more likely to lose two or more lines of best spectacle corrected visual acuity than those in the faculty group.

Posted by kjalali at 10:19 PM | Comments (0)

Comparison of Three Methods of Measuring Corneal Thickness and Anterior Chamber Depth

AJO 2006
To compare three different methods of measuring corneal thickness (CT) and anterior chamber depth (ACD), central CT (CCT), CT at four peripheral points, and central ACD were measured in 88 eyes of 44 healthy subjects with the Pentacam (rotating Scheimpflug camera; Oculus, Wetzlar, Germany), Orbscan I (scanning-slit topography system; Orbtek Inc, Salt Lake City, Utah, USA), and AC-Master (partial coherence interferometry; Zeiss Meditec, Jena, Germany), and the results were compared. The upper (lower) limits of agreement for CCT measurements were 7.9 (−22.2) μm between AC-Master and Pentacam, 17.6 (−32.5) μm between AC-Master and Orbscan, and 25.2 (−25.9) μm between Pentacam and Orbscan. Correlation was high between all three methods (r = 0.94 to 0.97). The upper and lower limits of agreement for ACD were 0.174 (−0.251) mm between AC-Master and Pentacam, 0.406 (−0.004) mm between AC-Master and Orbscan, and 0.384 (0.095) mm between Pentacam and Orbscan. Correlation was high between the three methods (r = 0.96 between Orbscan and Pentacam; others 0.92). Correlation was lower for the CT measurements at the four peripheral points. The CCT and ACD values obtained by Pentacam, Orbscan, and AC-Master measurements correlated well and showed few outliers. The two new systems (Pentacam, AC-Master) provide a reliable, easy-to-use, noncontact method of measuring CCT and ACD. Larger differences occurred only when measuring peripheral CT values, especially between AC-Master and the other two methods.

Posted by kjalali at 10:08 PM | Comments (0)

Vitrectomy potentially better than scleral buckle in pseudophakic eyes with detachment

OSN BREAKING NEWS
Primary pars plana vitrectomy offers “potential advantages” over scleral buckle surgery in patients with pseudophakic retinal detachment, according to a prospective study.
Periklis D. Brazitikos, MD, and colleagues randomly assigned 150 eyes of 150 patients with pseudophakic retinal detachment and proliferative vitreoretinopathy to scleral buckle surgery or primary pars plana vitrectomy.
The potential advantages of primary vitrectomy over scleral buckle included shorter operating time, a more accurate diagnosis of breaks, a higher reattachment with a single surgery and no axial length change, the study authors said.
Final visual acuity and retinal reattachment rates with multiple surgeries were similar between the two surgical procedures.

Posted by aman at 09:40 PM | Comments (0)

Intravitreal triamcinolone helpful in diabetic macular edema with hard exudates

OSN BREAKING NEWS
Intravitreal triamcinolone improved visual acuity and decreased the size of exudates in patients with chronic diabetic macular edema with severe foveal hard exudates, a Turkish study found.
Remzi Avci, MD, and Berkant Kaderli, MD, at Uludag University Hospital in Bursa studied the effects of triamcinolone injection in 33 eyes of 28 patients with chronic diabetic macular edema and severe foveal hard exudates. All patients underwent intravitreal injection of 4 mg of triamcinolone acetonide. The patients were divided into two groups: those with plaque-like exudates and those with dot-like scattered hard exudates. Patients were followed for 6 months.
At the final visit, hard exudates were completely resolved in 12% of eyes with plaque-like exudates and in 50% of those with dot-like exudates. Hard exudates decreased by 76% in the first group and by 50% in the second group.
Mean visual acuity also improved significantly in both groups, the authors said. “However, the visual acuity improvement was significantly worse in eyes with plaque-like exudates, suggesting the possible value of earlier treatment,” they reported.

Posted by aman at 09:36 PM | Comments (0)

Sustained-release implant enters phase 2 trial for dry AMD

OSN BREAKING NEWS A polymer implant that releases ciliary neurotrophic factor into the posterior segment has begun phase 2 testing in patients with dry age-related macular degeneration, the drug’s developer announced.
Neurotech’s NT-501 is an intraocular polymer implant containing human retinal epithelial cells genetically modified to secrete ciliary neurotrophic factor (CNTF), the company said in a press release. The implant is designed to continuously release CNTF for sustained periods of time.
An open-label phase 1 trial of NT-501 in patients with retinitis pigmentosa found that CNTF can be safely delivered into the vitreous of patients with retinitis pigmentosa, the company said. Some patients in that trial also experienced improvement in visual acuity scores.
The results from the phase 1 trial have encouraged us to study NT-501 in patients with atrophic macular degeneration affecting their central vision,” said Paul A. Sieving, MD, PhD, of the National Eye Institute. Two additional phase 2 studies of the implant in patients with retinitis pigmentosa are being planned for 2006, according to Neurotech.

Posted by aman at 09:30 PM | Comments (0)

Endoscopic Removal of Dermoid Cysts of the Eyebrow in Pediatric Patients.

Annals of Plastic Surgery. December 2005.

Direct excision of dermoid cysts of the brow may lead to a prominent facial scar. These scars can be completely avoided with an endoscopic temporal approach that places the incisions in the hair-bearing portion of the scalp. Over the past 10 years, this approach was offered to every pediatric patient with a cyst in the area of the brow, and outcomes were favorable.

Posted by afarahi at 05:04 PM | Comments (0)

January 03, 2006

Topical Cyclosporine A in Severe Steroid-Dependent Childhood Phlyctenular Keratoconjunctivitis

AJO,Jan,2006

We studied 11 children (13 eyes)with Severe Steroid-Dependent Childhood Phlyctenular Keratoconjunctivitis and a mean age of 9 years (range, 4 to 15 years). Inflammation was controlled in all the eyes within 14 days by topical CsA 2% four times daily, initially combined with topical dexamethasone for the first week. Inflammation did not recur during CsA monotherapy, during a mean follow-up of 12 ± 8 months (range, 6 to 31 months). CsA therapy was stopped in eight patients (10 eyes) after a mean treatment duration of 13 ± 9 months (range, 6 to 31 months), and no recurrences occurred during 10 ± 3 months of follow-up (range, 6 to 12 months). Local tolerance of CsA was good. None of the patients had detectable CsA blood levels. CsA was withdrawn in one case after 6 months, because of generalized skin rash.
Conclusions:Long-term topical CsA 2% therapy is safe and effective in children with phlyctenular keratoconjunctivitis associated with severe steroid-dependent corneal inflammation.

Posted by afarahi at 12:10 PM | Comments (0)

January 01, 2006

Anterior Chamber Depth Measurement With A-Scan Ultrasonography, Orbscan II, and IOLMaster

Optometry & Vision Science. 82(10):900-904, October 2005

HASHEMI, HASSAN MD; YAZDANI, KAMRAN MD, MPH; MEHRAVARAN, SHIVA MD; FOTOUHI, AKBAR MD, PhD

Methods. Forty-four myopic patients, 56.8% female, were enrolled in this prospective study. In all 88 eyes, the ACD was first measured with Orbscan II, followed by IOLMaster and EchoScan U3300, both under cycloplegia. The mean (+/- standard deviation) age and spherical equivalent were 30.2 +/- 8.5 years and -4.98 +/- 2.67 D, respectively. The difference between ACD measurements by these 3 devices was analyzed using the repeated-measures analysis of variance. Agreement between each pair of devices was assessed by computing the 95% limits of agreement (LoA). Orbscan II reliability was also evaluated by using the 95% LoA between 2 consecutive measurements. P value adjustments for multiple comparisons were performed using the Bonferroni method.
Results. There was a statistically significant difference between measurements made with the 3 devices (p < 0.001). The mean difference between Orbscan II and Echoscan ACD measurements was -0.03 +/- 0.12 mm, with the 95% LoA from -0.25 to +0.20 mm, and between IOLMaster and Echoscan measurements, it was +0.09 +/- 0.14 mm with the 95% LoA from -0.18 to +0.36 mm. On average, Orbscan II readings were lower and those of IOLMaster were higher than Echoscan readings. Both Orbscan II and IOLMaster agreed with Echoscan in measuring ACD. The 2 readings by Orbscan II had a 95% LoA of -0.05 and +0.07 mm that shows good reliability.
Conclusion. ACD measurement differences with the 3 studied devices proved to be statistically significant; however, these minor differences may be clinically negligible depending on the use of the measurement. As an advantage, both Orbscan II and IOLMaster are noncontact, and with their ACD measurements being valid, they may be considered suitable devices for this purpose. In addition, Orbscan II produces highly repeatable ACD measurements.

Posted by mmiraftab at 12:18 PM | Comments (0)

Astigmatism and its Determinants in the Tehran Population: The Tehran Eye Study

Ophthalmic Epidemiology December 2005,373 - 381

Hassan Hashemi , Elham Hatef , Akbar Fotouhi , Kazem Mohammad

Purpose: To determine the prevalence of astigmatism and its epidemiological risk factors in Tehran via a population-based study. Methods: By means of a stratified random cluster sampling, 6497 citizens representing a cross-section of the population of Tehran were selected from 160 clusters. Eligible people were recruited through a door-to-door household survey in the selected clusters and transferred to a clinic for an extensive eye examination and interview. The refractive status was determined with manifest refraction. Astigmatism was defined as cylinder worse than or equal to 0.5 D. High astigmatism was defined as a manifest cylinder ≥1.5 D. Results: Between August and December 2002, 4565 of the 6497 eligible individuals in the sample attended the interview and ophthalmic examination (a participation rate of 70.3%). The age- and gender-standardized prevalence of astigmatism was 50.2% (95% CI, 48.4% to 51.9%) on manifest refraction. High astigmatism was found in 490 right eyes (11.1%; 95% CI, 10.1% to 12.0%). Of 2532 participants with ametropia, 59.6 (95% CI, 57.6–61.5) had astigmatism. The percentages of with-the-rule, against-the-rule and oblique astigmatism were 33.6%, 36.9% and 29.3%, respectively. The proportion of type of astigmatism was significantly related to age (p < 0.001). The univariable analysis of astigmatism between family members yielded odds ratios of 1.47 (95% CI, 1.14 to 1.89, p = 0.003) for the association of astigmatism among siblings. After controlling for age, refractive errors and education, the pairwise sibling association remained statistically significant (OR 1.43, 95% CI, 1.08 to 1.88). Conclusion: These findings revealed a high prevalence of astigmatism in the population. Age, education and ametropia were the main predictors of astigmatism in Tehran. Our findings should be considered for case finding and astigmatism correction programs. Our data confirmed a modest familial aggregation for astigmatism.

Posted by mmiraftab at 12:15 PM | Comments (0)

Postoperative endophthalmities vs. toxic anterior segment syndrom(TASS)

OSN OPHTHALMIC HYPERGUIDE
Brandon L. Davis, MD · Laura Kearsley MD · Nick Mamalis, MD

Postoperative endophthalmitis is a rare but potentially devastating complication of cataract surgery. Postoperative endophthalmitis can be either sterile or infectious. Sterile endophthalmitis is also known as the toxic anterior segment syndrome (TASS). The overall incidence of endophthalmitis has decreased over the past several decades. This decrease has mostly been a result of improved surgical technique and patient preparation. Modern estimates indicate that the incidence of infectious endophthalmitis ranges from 0.13% to 0.7%.1-4 Culture positive infectious endophthalmitis accounts for approximately 69% of cases.5 There are multiple potential causes of TASS including toxic effects from intraocular fluids, medications, lenses, instruments, endotoxins, and sterilization techniques. It is imperative to differentiate infectious endophthalmitis from TASS, as the treatments and positive outcomes are different.
Clinical Course
There is significant overlap between the clinical presentation of sterile and infectious endophthalmitis. The presence of negative cultures, timing of onset, and response to therapy can help distinguish between the two entities. Often, the presenting signs and symptoms of infectious endophthalmitis occur within the first 48 to 72 hours after surgery. If endophthalmitis is caused by fungal or less virulent organisms, the onset of symptoms can occur as late as weeks to months after surgery. TASS can occur immediately, usually within the first 24 hours following surgery. However, there may also be a delayed onset toxic reaction.
TASS usually presents sooner than infectious endophthalmitis (12 to 24 hours after surgery) and differs from infectious endophthalmitis in presentation. Patients often have decreased visual acuity, corneal edema, a nonreactive, dilated pupil, and a moderate to severe anterior chamber reaction with cells, flare, hypopyon, and especially fibrin. Pain is mild to moderate if present. Patients with TASS can have marked corneal edema and even permanent, irreversible corneal decompensation.9 The corneal edema is characteristically "limbus to limbus."
TASS
TASS is implicated when no obvious cause for postoperative inflammation can be found. As opposed to being infectious, these cases are believed to be secondary to nonphysiologic factors. Cases of TASS tend to be clustered and are often a result of patients' reaction to abnormal solutions, contamination of equipment, and/or IOLs. Potential causes for intraocular reactions include abnormal irrigation solutions (abnormal pH or ionic composition), denatured viscoelastic, residual detergent in reusable equipment, and chemical residues left after sterilization. Patients can also have reactions to residual lens cortex, preservatives in ophthalmic solutions, and endotoxins not destroyed by the sterilization process. Kreisler and coauthors24 described an outbreak of TASS secondary to Klebsiella endotoxin. The ultrasound bath used to clean the instruments became contaminated with bacteria. Sterilization killed the bacteria, but a heat-stable endotoxin remained on the instruments and caused an outbreak of TASS. Other sources include reactions to the finish, design, chemical structure, or sterilization of an IOL.
In many cases, the cause of TASS outbreaks is not known, but a few case reports have been published specifically linking cause and effect. The first report of an adverse toxic or inflammatory reaction was in 1987, in which a series of patients developed a reaction to the viscoelastic. It appears that the viscoelastic, sodium hyaluronate, within reusable cannulas was denatured during heat sterilization.26 Other early cases were believed to be due to detergent and viscoelastic residues trapped inside irrigating cannulas, miotic agents such as 1% Miochol (acetylcholine chloride, CIBA Vision) and aminoglycoside antibiotics inadvertently penetrating through the surgical wound.
A more recent study postulated an association between TASS and the MemoryLens (Bausch & Lomb, Claremont, Calif.). In the report, 10 patients developed sterile endophthalmitis at a mean of 8 days postoperatively. All patients responded to steroids and were consistent with a delayed-onset, acute toxic reaction. Jehan and colleagues25 postulated that the hydrophilic nature of the lens allowed for a water-soluble inflammatory agent to penetrate the IOL and cause an inflammatory reaction. The authors also considered the possibility that materials used during the manufacturing, polishing or packaging process could have caused this outbreak. The MemoryLens has since been recalled (April 2000) secondary to similar reports of inflammation.
Another case series found an association between toxic endothelial cell destruction and intraocular benzalkonium chloride (a cationic detergent that is commonly used as a preservative in topical ophthalmic solutions). In this series, 12 of 19 patients developed corneal edema after using balanced salt solution preserved with benzalkonium chloride at 0.001%. Other toxic preservatives include sodium bisulfite at 0.1% and thimerosal at 0.01%. Corneal endothelial damage can easily occur if any hospital staff mistakenly replaces irrigating solutions with increased amounts of preservative.
Another case series reported nine cases of sterile endophthalmitis after use of refrigerated balanced salt solution. Before this outbreak, it was believed that cold balanced salt solution might decrease endothelial cell loss and postoperative inflammation. Sixty-eight cases were performed under these conditions and nine patients developed TASS. The only common technique in this series was the use of cold balanced salt solution. The authors postulated that the cold balanced salt solution decreased tissue swelling, allowing for entry of potentially toxic subconjunctival fluid.
Treatment of TASS has not been as thoroughly studied as infectious endophthalmitis. Part of this difference is due to the fact that TASS is often believed to be infectious upon presentation. Often, the diagnosis of TASS is only assigned after cultures are found to be negative or a cause is discovered. Several cases described in the literature were defined as TASS secondary to negative cultures and improvement despite discontinuation of antibiotics.27 Treatments used in published case reports vary considerably, making generalized recommendations difficult. The most common factor among case reports includes use of corticosteroids to decrease inflammation.25,28,37 This consists of an intense regimen of hourly topical steroids (prednisolone acetate 1%) with or without a course of oral steroids (prednisone). If intravitreal corticosteroids are used, dexamethasone at 400 mg per 0.1 mL is recommended.
The patients should be followed closely, especially if there is any question of an infectious etiology. Inflammation secondary to TASS will respond readily to topical steroid treatment, which may then be tapered accordingly. These patients may also have concomitant trabecular meshwork damage and must be monitored closely for IOP increases. Last, diffuse corneal edema occurs secondary to endothelial damage and may result in permanent corneal clouding requiring subsequent penetrating keratoplasty.

Posted by aman at 03:24 AM | Comments (0)

Pearls for Toric IOL implantation

OSN OPHTHALMIC HYPERGUIDE
David F. Chang, MD
In November 1998, the Staar (Monrovia, Calif) plate haptic toric IOL became the first toric lens approved by the U.S. Food and Drug Administration. Earlier and concurrent studies have suggested that the plate haptic design is superior to that of curved haptic designs in terms of long-term rotational stability.1,2 Using serial digital photographs, Patel demonstrated that late postoperative rotation was unusual with plate haptic lenses, but more frequent with 3-piece designs. However, Patel's study also confirmed that both lens designs can rotate during the immediate postoperative period; the plate haptic design rotated more frequently.2 Presumably, it is not until the capsular bag contracts that the corners of the plate haptic IOL are able to resist natural rotational forces. Patel’s study used a 10.5-mm plate haptic IOL, which is shorter than the two toric IOL sizes (10.8 mm and 11.2 mm) available from Staar.
have found corneal limbal relaxing incisions (LRIs) to be effective in reducing low amounts of astigmatism (less than 2 D). I use a preset, 600-mm blade and the Gills nomogram. Although this method does not adjust for individual variation in peripheral corneal thickness and corneal diameter, the dominant variable is the patient’s age. As with all incisional keratotomy, increasing age amplifies the effect of a given incision length. In addition, the greater the amount of targeted astigmatism effect, the more variable and unpredictable are the results of LRIs.
Toric IOL Indications and Specifications
For these reasons, I have found the toric IOL to be particularly appropriate for two types of patients. The first indication is cataract patients younger than 65 years with 2 D or more of astigmatism, but whose age significantly reduces the attainable effect from incisional keratotomy. The second group consists of patients with the largest degrees of astigmatism (e.g., more than 3 D). In addition to more unpredictability, against-the-rule astigmatism in these patients requires combining the temporal clear corneal incision with a temporal LRI. Slight override of the incision edges can cause significant discomfort and foreign body sensation for these patients.
The Staar toric plate haptic IOL has large haptic fenestrations, and is available in two astigmatic powers and two lengths. The 2-D toric IOL corrects approximately 1.50 D of keratometric astigmatism, whereas the 3.5-D toric IOL corrects approximately 2.25 D. The Staar "TF" lens was the original FDA-studied design. It has an overall length of 10.8 mm. Subsequently, Staar released the longer, 11.2 mm "TL" model for spherical powers of less than 23.5 D. The haptics of the longer lens have a matte finish to make them less slippery.
The spherical power of the toric IOL is calculated in the same way as for a conventional IOL. Next, the astigmatic power is selected without having to adjust the spherical power. Hash marks on the IOL allow this cylindrical power to be surgically aligned with the steeper "plus" axis of astigmatism .To avoid any potential influence of lenticular astigmatism, one should use the keratometric reading, rather than the refraction, for selecting the IOL toric power and axis. Rigid contact lens wear should be discontinued for 1 week to obtain more accurate keratometric readings. These patients should be informed that any residual postoperative astigmatism can be corrected only with spectacles or a toric soft contact lens.
Misalignment of the toric IOL axis reduces the amount of astigmatism correction. With 10° of axis deviation, one-third of the effect is lost. With 20° of axis deviation, two-thirds of the effect is lost. Lens misalignment of more than 30° produces a net increase in astigmatism .In the FDA study data, 24% of the toric IOLs ended up more than 10° off axis (12% were more than 20° off, 8% were more than 30° degrees off, and 5% were more than 45° degrees off axis). The FDA studied the shorter 10.8 mm toric size.
So far, significant late rotation of the lenses has not been reported, consistent with the published Patel findings.3 Thus, the key to success with the toric IOL is in avoiding early postoperative rotation of the lens. This depends on having an adequately long IOL for the patient’s capsular bag diameter. The learning curve for my first 40 cases underscores this point.
Current Technique and Results
-Always use the longer "TL" IOL if available in the desired power. Use a cohesive viscoelastic, for example, Healon (sodium hyaluronate, Pharmacia), Provisc (1% sodium hyaluronate, Alcon), Biolon (sodium hyaluronate, Allergan). Compared to dispersive viscoelastics, these are less likely to coat and lubricate the IOL surface.
-Remove viscoelastic trapped behind the IOL with irrigation and aspiration to maximize contact between the IOL and the posterior capsule.
-Do not overinflate the eye. Leaving the eye somewhat "softer" than usual probably allows the flaccid capsular bag to collapse around the IOL more quickly.
-Use an astigmatically neutral, temporal clear corneal incision.
implant the toric IOL under topical anesthesia without postoperative patching or shields. With the patient sitting upright on the operating table just before surgery, the 6 o’clock limbus is marked with a pen. Once under the microscope, a Mendez-style degree gauge is then used to orient two limbal ink marks that identify the desired axis. Later, the IOL axis marks can be aligned with these ink marks and double checked against the preoperative notes or chart.
Preoperatively, I inform patients of the potential need for surgical repositioning, and postoperatively, I perform a dilated exam on postoperative days 1 and 6 to check the IOL axis.Any rotation tends to occur between the time of surgery and the first postoperative morning. I have yet to record any significant change from the axis on postoperative day 1. Based on my experience with three badly misaligned cases, I would perform repositioning by 1 week or earlier.Once the capsular bag fully contracts (e.g., by 2 weeks with my third case), more force is required to rotate the IOL, and this may increase the chance of tearing the capsular bag.
Excellent rotational stability was achieved with this technique in my series of 44 consecutive TL (11.2 mm) toric implants: 68% were within 5° of target axis; 91% were within 10° of target axis; and 98% were within 15° of target axis. My repositioning rate was 0% with the longer TL IOL compared with 50% with the shorter TF IOL (three of six cases).
Conclusion
Toric IOLs are an excellent complement to corneal astigmatic incisions. They are helpful in those cases where LRIs are not powerful or predictable enough. Proper IOL sizing is critical for initial rotational stability. Until the capsular bag begins to contract within the first day or so, a plate haptic IOL that is too small for the bag can rotate. With the availability of the longer 11.2 mm model, toric IOLs have become a valuable addition to my practice.

In November 1998, the Staar (Monrovia, Calif) plate haptic toric IOL became the first toric lens approved by the U.S. Food and Drug Administration. Earlier and concurrent studies have suggested that the plate haptic design is superior to that of curved haptic designs in terms of long-term rotational stability.1,2 Using serial digital photographs, Patel demonstrated that late postoperative rotation was unusual with plate haptic lenses, but more frequent with 3-piece designs. However, Patel's study also confirmed that both lens designs can rotate during the immediate postoperative period; the plate haptic design rotated more frequently.2 Presumably, it is not until the capsular bag contracts that the corners of the plate haptic IOL are able to resist natural rotational forces. Patel’s study used a 10.5-mm plate haptic IOL, which is shorter than the two toric IOL sizes (10.8 mm and 11.2 mm) available from Staar.
have found corneal limbal relaxing incisions (LRIs) to be effective in reducing low amounts of astigmatism (less than 2 D). I use a preset, 600-mm blade and the Gills nomogram. Although this method does not adjust for individual variation in peripheral corneal thickness and corneal diameter, the dominant variable is the patient’s age. As with all incisional keratotomy, increasing age amplifies the effect of a given incision length. In addition, the greater the amount of targeted astigmatism effect, the more variable and unpredictable are the results of LRIs.
Toric IOL Indications and Specifications
For these reasons, I have found the toric IOL to be particularly appropriate for two types of patients. The first indication is cataract patients younger than 65 years with 2 D or more of astigmatism, but whose age significantly reduces the attainable effect from incisional keratotomy. The second group consists of patients with the largest degrees of astigmatism (e.g., more than 3 D). In addition to more unpredictability, against-the-rule astigmatism in these patients requires combining the temporal clear corneal incision with a temporal LRI. Slight override of the incision edges can cause significant discomfort and foreign body sensation for these patients.
The Staar toric plate haptic IOL has large haptic fenestrations, and is available in two astigmatic powers and two lengths. The 2-D toric IOL corrects approximately 1.50 D of keratometric astigmatism, whereas the 3.5-D toric IOL corrects approximately 2.25 D. The Staar "TF" lens was the original FDA-studied design. It has an overall length of 10.8 mm. Subsequently, Staar released the longer, 11.2 mm "TL" model for spherical powers of less than 23.5 D. The haptics of the longer lens have a matte finish to make them less slippery.
The spherical power of the toric IOL is calculated in the same way as for a conventional IOL. Next, the astigmatic power is selected without having to adjust the spherical power. Hash marks on the IOL allow this cylindrical power to be surgically aligned with the steeper "plus" axis of astigmatism .To avoid any potential influence of lenticular astigmatism, one should use the keratometric reading, rather than the refraction, for selecting the IOL toric power and axis. Rigid contact lens wear should be discontinued for 1 week to obtain more accurate keratometric readings. These patients should be informed that any residual postoperative astigmatism can be corrected only with spectacles or a toric soft contact lens.
Misalignment of the toric IOL axis reduces the amount of astigmatism correction. With 10° of axis deviation, one-third of the effect is lost. With 20° of axis deviation, two-thirds of the effect is lost. Lens misalignment of more than 30° produces a net increase in astigmatism .In the FDA study data, 24% of the toric IOLs ended up more than 10° off axis (12% were more than 20° off, 8% were more than 30° degrees off, and 5% were more than 45° degrees off axis). The FDA studied the shorter 10.8 mm toric size.
So far, significant late rotation of the lenses has not been reported, consistent with the published Patel findings.3 Thus, the key to success with the toric IOL is in avoiding early postoperative rotation of the lens. This depends on having an adequately long IOL for the patient’s capsular bag diameter. The learning curve for my first 40 cases underscores this point.
Current Technique and Results
-Always use the longer "TL" IOL if available in the desired power. Use a cohesive viscoelastic, for example, Healon (sodium hyaluronate, Pharmacia), Provisc (1% sodium hyaluronate, Alcon), Biolon (sodium hyaluronate, Allergan). Compared to dispersive viscoelastics, these are less likely to coat and lubricate the IOL surface.
-Remove viscoelastic trapped behind the IOL with irrigation and aspiration to maximize contact between the IOL and the posterior capsule.
-Do not overinflate the eye. Leaving the eye somewhat "softer" than usual probably allows the flaccid capsular bag to collapse around the IOL more quickly.
-Use an astigmatically neutral, temporal clear corneal incision.
implant the toric IOL under topical anesthesia without postoperative patching or shields. With the patient sitting upright on the operating table just before surgery, the 6 o’clock limbus is marked with a pen. Once under the microscope, a Mendez-style degree gauge is then used to orient two limbal ink marks that identify the desired axis. Later, the IOL axis marks can be aligned with these ink marks and double checked against the preoperative notes or chart.
Preoperatively, I inform patients of the potential need for surgical repositioning, and postoperatively, I perform a dilated exam on postoperative days 1 and 6 to check the IOL axis.Any rotation tends to occur between the time of surgery and the first postoperative morning. I have yet to record any significant change from the axis on postoperative day 1. Based on my experience with three badly misaligned cases, I would perform repositioning by 1 week or earlier.Once the capsular bag fully contracts (e.g., by 2 weeks with my third case), more force is required to rotate the IOL, and this may increase the chance of tearing the capsular bag.
Excellent rotational stability was achieved with this technique in my series of 44 consecutive TL (11.2 mm) toric implants: 68% were within 5° of target axis; 91% were within 10° of target axis; and 98% were within 15° of target axis. My repositioning rate was 0% with the longer TL IOL compared with 50% with the shorter TF IOL (three of six cases).
Conclusion
Toric IOLs are an excellent complement to corneal astigmatic incisions. They are helpful in those cases where LRIs are not powerful or predictable enough. Proper IOL sizing is critical for initial rotational stability. Until the capsular bag begins to contract within the first day or so, a plate haptic IOL that is too small for the bag can rotate. With the availability of the longer 11.2 mm model, toric IOLs have become a valuable addition to my practice.

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