Donna Gilbert

An Evaluation of Optic Disc and Nerve Fiber Layer Examinations in Monitoring Progression of Early Glaucoma Damage

From annual examinations of 813 ocular hypertensive eyes, the authors compared optic disc and nerve fiber layer photographs in 2 age-matched subgroups: 37 eyes that converted to abnormal visual field tests at the end of a 5-year period and 37 control eyes that retained normal field tests. Disc change was detected in only 7 of 37 (19%) converters to field loss and in 1 of 37 (3%) controls. Progressive nerve fiber layer atrophy was observed in 18 of 37 (49%) converters and in 3 of 37 (8%) controls. Serial nerve fiber layer examination was more sensitive than color disc evaluation in the detection of progressive glaucoma damage at this early stage of glaucoma. The evaluation of cup-to-disc ratio or of the nerve fiber layer appearance in the initial photograph taken 5 years before field loss were equally predictive of future field damage. The position of nerve fiber layer defects was highly correlated with the location of subsequent visual field loss.

Estimating Progression of Visual Field Loss in Glaucoma

PURPOSE The authors estimated the prevalence and rates of progressive visual field loss in glaucoma patients followed annually for a median of 6.3 years. METHODS Linear regression was used to estimate rates of progression of mean deviation, corrected pattern standard deviation (CPSD), clusters of locations based on the Glaucoma Hemifield Test (GHT), and location specific changes in C-30-2 fields of the Humphrey Analyzer. RESULTS Sixty-seven eyes of 56 patients whose first two consecutive fields were abnormal on GHT were included. Almost all patients were under treatment or had undergone surgery for glaucoma. Visual field deteriorated in 19 (28%) eyes based on worsening of one or more CPSD, GHT clusters, or individual test locations (regression slopes significantly different from zero). Corrected pattern standard deviation deteriorated in 5 eyes, at least one GHT cluster deteriorated in 17 eyes, and one or more individual test locations deteriorated in 15 eyes. For those whose visual field deteriorated, CPSD increased by 0.9 dB/year. Glaucoma Hemifield Test clusters declined by between 1.4 and 2.4 dB/year. Deterioration at individual locations ranged from 1.0 to 5.0 dB/year. Age, but not baseline visual field severity, was predictive of further visual field loss. The odds ratio for the association between progressive visual field loss and thinning of the nerve fiber layer was 1.81 (95% confidence interval: 0.52, 6.33), and 3.78 (95% confidence interval: 0.80, 18.16) for the association between progressive visual field loss and optic disc changes during follow-up based on masked photograph readings. CONCLUSIONS Less than one in three eyes of patients with glaucoma had any progressive field loss. Average changes in threshold sensitivities of less than 1 dB/year could not be detected with seven fields done over 6 years. Larger changes or increased frequency of visual field testing would need to occur before smaller changes could be detected statistically.

Quantitative Grading of Nerve Fiber Layer Photographs

PURPOSE The authors have developed a simple method for semi-quantitative grading of atrophy of the peripapillary nerve fiber layer (NFL) in black and white photographs. METHODS An experienced observer read sets of NFL photographs using a four-level grading system. Five observers with varying levels of experience at ophthalmic examination were taught the grading system in approximately 4 hours, and their readings were compared with those of the expert. RESULTS The reproducibility of readings by an experienced observer was excellent. The validity of the grading system was confirmed by comparisons to visual field findings, as well as to cup-to-disc ratios in the same eyes. The agreement with the expert by the five trained graders was good. CONCLUSIONS Grading of the NFL could be useful both to monitor development of early glaucoma damage clinically and to measure progression of glaucoma damage in clinical trials research. The grading system can be taught readily to other observers.

Corneal complications associated with topical ophthalmic use of nonsteroidal antiinflammatory drugs

Purpose: To explore the potential association between adverse corneal events and the use of topical nonsteroidal antiinflammatory drugs (NSAIDs). Setting: Practice‐based reports. Methods: A detailed case‐reporting form and request for medical records were sent to all practices reporting cases of corneal or conjunctival pathology in association with the use of topical NSAIDs to the American Society of Cataract and Refractive Surgery. Cases were classified as “mild,” “moderate,” or “severe” according to predetermined clinical criteria. Results: Records of 140 eyes (129 patients) were reviewed; 51 cases (36.4%) were mild, 55 (39.3%) moderate, and 34 (24.3%) severe. An association with a specific topical NSAID was confirmed in 117 cases (81.8%). Most confirmed cases (53.8%) involved generic diclofenac (Falcon). Cases associated with brand diclofenac (Voltaren®, CIBA Vision) and ketorolac (Acular®, Allergan) were more likely to have ocular comorbidity and to have received significantly higher total doses of NSAIDs. Neither “off‐label” use nor use of any specific agent was associated with severe compared to mild or moderate disease. However, patients with more severe adverse events were more likely to have a history of diabetes, previous surgery in the affected eye, and surgery other than cataract. Cases not occurring in the perioperative period had significantly worse outcomes, had significantly more ocular comorbidities, and received nearly 3 times the dose of NSAIDs. Conclusions: While topical NSAIDs as a class may be associated with severe adverse events, such events appeared to require potentiation in the form of high total doses, ocular comorbidities, or both with Acular and Voltaren. Severe adverse events might have been more likely to occur at lower doses and in routine postoperative settings with generic diclofenac.

Outcomes and Bleb-Related Complications of Trabeculectomy

PURPOSE To determine rates of success and complications of trabeculectomy surgery. DESIGN Case series. PARTICIPANTS Consecutive patients undergoing trabeculectomy by 2 surgeons between May 2000 and October 2008. INTERVENTION By using the Wilmer Institutes billing database, we identified all patients at least 12 years of age coded as having undergone trabeculectomy between May 2000 and October 2008 by 1 of 2 glaucoma surgeons and whose surgery was not combined with another operation. From the chart, we abstracted demographic information on the patients and clinical characteristics of the eyes. The Kaplan-Meier product-limit method and Cox proportional hazard models were used to look at success rates and characteristics associated with inadequate intraocular pressure (IOP) reduction. Complications were tabulated. MAIN OUTCOME MEASURES (1) Success rate of trabeculectomy, as determined by the achievement of each of 4 different IOP goals, with or without IOP-lowering medications; and (2) incidence of surgical complications. RESULTS During the study period, 797 eyes of 634 persons underwent trabeculectomy without concurrent surgery. The success rates 4 years after surgery, with or without the use of IOP-lowering eye drops, were 70%, 72%, 60%, and 44%, for achievement of target IOP, ≤18 mmHg and ≥20% IOP reduction, ≤15 mmHg and ≥25% reduction, and ≤12 mmHg and ≥30% reduction, respectively. Increased chance of success was associated with European-derived race; use of mitomycin C (MMC); higher concentrations of MMC, when used; and higher preoperative IOP. Age and previous intraocular surgery were not associated with surgical success. Complications included worsening lens opacity in 242 of 443 phakic eyes (55%), loss of ≥3 lines of acuity (Snellen) in 161 eyes (21%), surgery for bleb-related problems in 70 eyes (8.8%), and infection occurring >6 weeks after surgery in 27 eyes (3.4%). A total of 101 eyes of 94 patients had at least 1 subsequent operation for inadequate IOP control. CONCLUSIONS Trabeculectomy surgery performed by 2 experienced glaucoma specialists achieved target IOP at 4 years in 70% of those operated and was associated with progressive cataract and small risks of bleb-related complications. These results are comparable to those reported in smaller series.

Comparison of Limbus-Based and Fornix-Based Trabeculectomy: Success, Bleb-Related Complications, and Bleb Morphology

PURPOSE To compare the success and complications of trabeculectomy performed with limbus-based and fornix-based conjunctival approaches. DESIGN Retrospective case series with some prospective data collection. PARTICIPANTS Consecutive patients undergoing trabeculectomy by 2 surgeons between May 2000 and October 2008. INTERVENTION We performed limbus-based operations during the first 4 years and fornix-based operations during the last 4 years. We collected data by chart review and by examination at the most recent visit. For each follow-up visit, we defined success as undergoing no further glaucoma procedure and achieving one of our intraocular pressure (IOP) criteria. We used Kaplan-Meier survival analysis, Cox proportional hazards models, and generalized estimating equation (GEE) analysis. During 2009, 439 trabeculectomy sites of 347 patients were quantitatively assessed by the Indiana bleb grading system. MAIN OUTCOME MEASURES (1) Success rate of trabeculectomy, as determined by the achievement of each of our different IOP goals, with or without IOP-lowering medications; and (2) incidence of surgical complications. RESULTS During the 4 years after surgery, the success rates of limbus-based and fornix-based trabeculectomy were not statistically different for any of our IOP criteria. Blebs after limbus-based surgery were more likely to be graded as higher and to be avascular (GEE model, both P < 0.0001). Four percent of eyes experienced late-onset bleb leaks within 4 years after both limbus- and fornix-based operations; however, limbus-based cases developed bleb leaks significantly later than did fornix-based cases (2.1 vs. 1.0 years; P=0.002, GEE model). Late bleb-associated infection during the first 4 years after surgery occurred more often in limbus-based operations, although statistical significance was borderline (P=0.054, Cox model). Symptomatic hypotony during all available follow-up was more common with fornix-based operations (P=0.01, GEE model). Eyes undergoing the fornix-based operation had a greater risk of cataract surgery in the 4-year period after surgery (P=0.02, Cox model), and fornix-based cases requiring cataract surgery had the operation earlier than limbus-based cases (P=0.002, GEE model). CONCLUSIONS Success rates are similar between limbus-based and fornix-based trabeculectomy. Limbus-based procedures produce higher, more avascular blebs, with a greater risk of infection. Fornix-based procedures have more symptomatic hypotony and more and earlier cataract development.

The relationship between optic disc area and open-angle glaucoma: the Baltimore Eye Survey.

PURPOSE To determine if eyes with larger optic disc area are more likely to have open-angle glaucoma or to have glaucoma at lower intraocular pressure (IOP). METHODS Data were collected from a population-based sample of adults residing in East Baltimore, consisting of demographic information, ocular examinations, automated and static/kinetic visual field tests, IOP as measured by applanation tonometry, and image analysis of the optic disc. Optic disc area was calculated using refractive error to correct magnification. Open-angle glaucoma was defined by visual field and optic disc criteria. One eye from each of 75 patients with glaucoma was compared to those of 3,518 subjects without glaucoma. RESULTS Although optic disc area was somewhat larger among patients with glaucoma than control subjects, in a regression model adjusting for age, gender, and race, the significance of this difference had a probability of 0.06. Among patients with glaucoma, disc area was not related to IOP level measured at study examination. CONCLUSION Disc area is a weak risk factor for open-angle glaucoma. Disc area did not differ between patients with glaucoma who had lower IOP and those who had higher IOP among a group with glaucoma that were identified in a population survey.

A randomized trial of visual impairment interventions for nursing home residents: Study design, baseline characteristics and visual loss

Introduction Visual impairment among nursing home residents is higher than in community-dwelling elderly. The provision of eye care services may be beneficial to nursing home patients. Our project, a randomized trial of vision restoration and rehabilitation in nursing home residents, compares usual care to targeted interventions. In this paper, we present the baseline characteristics of our sample within the nursing homes. Methods Twenty-eight nursing homes on Maryland’s Eastern Shore were matched in pairs by size and payment type. Each pair was randomized to usual care or targeted intervention. Habitual and bestcorrected acuity was attempted, using standard letter symbol/charts and grating acuity charts. Visual impairment was vision in the better eye <20/40 on letter and/or grating acuity. The MiniMental State Examination (MMSE) was used to determine cognitive impairment. Results Of those participants eligible to be screened, 40% had severe cognitive impairment (MMSE score 0-9). No measure of acuity could be ascertained on 18% of eligibles. Among the 1305 persons with acuity data, 38% had presenting vision worse than 20/40. After refractive correction, 29% had visual impairment. There was no difference by race or gender in those with visual impairment, although they were older, compared to those without visual loss. Conclusions The nursing home residents had high rates of both cognitive impairment and visual impairment, creating a challenging environment for visual intervention. By improving access to eye care within the context of the clinical trial, and changing either the magnitude of visual loss or the resultant impact on function, we hope to demonstrate a change in the quality of life for nursing home residents.

The Effect of Test Duration on Catch Trial Responses in Automated Perimetry

The effect of test duration on fixation losses, and false-positive and false-negative catch trial responses was examined in 361 eyes of 203 ocular hypertensive patients. These were recorded at 5-min intervals during automated perimetric testing with the Humphrey field analyzers C-30–2 program. There was no statistically significant change in the distribution of false-positive and -negative response rates as the test progressed, hut the proportion of tests with at least one false-negative response per 5-min interval did increase toward the end of the test. Fixation losses were common and showed no consistent pattern over the course of testing, but were related to technician test administration technique. Test duration did not appear to affect catch trial responses over the course of testing.