Aaron Kassoff

New visual acuity charts for clinical research.

Three new visual acuity charts facilitate quantitative use of visual acuity test results. The charts have high-contrast lettering on washable white polystyrene. Each line has five Sloan letters; the lines are of equal difficulty and there is a geometric progression in letter size from line to line. This provides a similar task for each line on the chart with the letter size being the only variable. Charts with different letter sequences are used for testing right and left eyes.

Photocoagulation Treatment of Proliferative Diabetic Retinopathy: The Second Report of Diabetic Retinopathy Study Findings

Data from the Diabetic Retinopathy Study (DRS) show that photocoagulad inhibited the progression of retinopathy. These beneficial effects were noted to some degree in all those stages of diabetic retinopathy which were included in the Study. Some deleterious effects of treatment were also found, including losses of visual acuity and constriction of peripheral visual field. The risk of these harmful effects was considered acceptable in eyes with retinopathy in the moderate or severe retinopathy in the moderate or severe proliferative stage when the risk of severe visual loss without treatment was great. In early proliferative or severe nonproliferative retinopathy, when the risk of severe visual loss without treatment was less, the risks of harmful treatment effects assumed greater importance. In these earlier stages, DRS findings have not led to a clear choice between prompt treatment and deferral of treatment unless and until progression to a more severe stage occurs.

Relative Letter and Position Difficulty on Visual Acuity Charts From the Early Treatment Diabetic Retinopathy Study

Ten Sloan letters were used in the visual acuity charts developed for use in the Early Treatment Diabetic Retinopathy Study. We used the data from the 3,710 Early Treatment Diabetic Retinopathy Study subjects to investigate the relative difficulty of the ten Sloan letters and to evaluate whether the position of a letter on a line affected its relative difficulty. In general, our findings were consistent with those of the previous study. The four letters with curved contours (C, O, S, and D) were more difficult to discern at threshold than the six letters (Z, N, H, V, R, and K) composed of straight lines. Our data demonstrate that under these test conditions, letters at the end of a line are more likely to be read incorrectly than letters at the beginning of the line. This finding indicates that these data are probably not useful for evaluating possible crowding phenomena.

Treatment of endophthalmitis after cataract extraction.

Background: A series of 34 patients was prospectively treated for postoperative endophthalmitis according to a specific protocol. The data are from the pilot study performed before initiation of the Endophthalmitis Vitrectomy Study (EVS). Methods: Patients with bacterial endophthalmitis that developed within 6 weeks of cataract extraction received intravitreal amikacin and vancomycin, subconjunctival and topical antimicrobials and corticosteroids, and systemic corticosteroids. All patients had diagnostic samples removed from the aqueous and vitreous, with randomized assignment to immediate vitrectomy versus vitreous tap and treatment with or without intravenous antibiotics. Outcome was evaluated 3 and 9 months after treatment. Results: At the 9-month visit, visual acuity was 20/50 or better in 49% of all eyes, 20/200 or better in 79%, and 5/200 or better in 91%. Media clarity was such that a “20/40 or better view” of the retina was present in 71 % of patients at 3 months and in 97% at 9 months. Conclusion: This is one of the largest series of patients with postoperative endophthalmitis treated and evaluated under a prospective protocol and without selection bias. Each of the options used in this study to treat postoperative endophthalmitis may result in good visual results.

Vitreous hemorrhage and the Valsalva maneuver in proliferative diabetic retinopathy.

A 59-year-old man with bilateral proliferative diabetic retinopathy underwent fluorescein angiography as a baseline study. Soon after intravenous injection of fluorescein, the patient had an extended episode of vomiting resulting in bilateral vitreous hemorrhages. Photographic evidence is presented that confirms the clinical impression that vitreous hemorrhage may be precipitated by a Valsalva maneuver.

The Care of Diabetic Patients by Ophthalmologists in New York State

All ophthalmologists in New York State whom the authors could identify through state sources and professional societies (n = 1655) were surveyed about eye care of diabetic patients. Over 90% recommended at least annual retinal examinations for the presented hypothetical patients. Ninety-four percent said they usually (31%) or almost always (63%) recommend laser treatment for proliferative retinopathy, while 6% said they occasionally or almost never recommend such treatment. Almost all the latter physicians were general ophthalmologists. The decision to treat macular edema was highly dependent on the quality of the patients vision. The percentage who usually or almost always recommend laser treatment for macular edema was 24% when the patients vision was excellent, 63% when vision was mildly compromised, but 73% when vision was significantly compromised. General ophthalmologists and retina specialists differed significantly in their recommendations for follow-up and treatment of diabetic retinopathy. Ophthalmology 96:739-745, 1989.

Care of Diabetic Patients by Optometrists in New York State

Objective This study was undertaken to learn about the involvement of optometrists in the eye care of diabetic patients in New York and to collect baseline data for planning intervention programs in diabetic eye disease. Research Design and Methods This study was conducted by a mail survey being sent to all optometrists in New York whom we could identify through state sources (n = 2270). Three follow-up mailings were conducted. Results Eighty-six percent who received our mailing responded, 87%of whom reported that they see diabetic patients. Analysis was confined to this 87%. Routine retinal examinations were provided by 68% of the respondents who see diabetic patients, 62% of whom dilate the pupils. Sixty-eight percent who see diabetic patients diagnose retinopathy solely by their own examination, and 60% of these dilate. Follow-up of retinopathy was provided by 15% of optometrists who see diabetic patients, 90% of whom dilate the pupils of their diabetic patients. Twenty-five percent of respondents who see diabetic patients refer them to an ophthalmologist for diagnosis of retinopathy, and 67% refer all retinopathy patients to an ophthalmologist for follow-up. Although 91% of respondents recommended eye examinations at least annually for diabetic patients, only 68% specifically recommended annual examinations through dilated pupils. Those who dilate were significantly more likely to recommend annual dilated examinations than those who do not dilate, regardless of practice setting. Conclusions These findings indicate that optometrists as a group see many diabetic patients. Intervention strategies should include increased emphasis on the use of dilation when examining diabetic patients and annual dilated retinal examinations.

White Centered Retinal Hemorrha es in Diabetic Retinopathy

Two hundred fifteen diabetic patients (430 eyes) with early proliferative retinopathy, moderate-to-severe nonproliferative retinopathy, and/or diabetic macular edema in each eye were examined for the presence of white centered retinal hemorrhages (WCRHs). Of the eyes examined, 15.6% demonstrated at least one WCRH and 4.9% showed five or more WCRHs. The prevalence of WCRHs was not significantly related to hypertension, anemia, leukocytosis, thrombocytopenia, thrombocytosis, abnormalities of coagulation, increased serum creatinine, or ingestion of oral contraceptives. Local factors associated with microvascular damage and repair are likely responsible for WCRHs in diabetics. Microaneurysms are at the center of many diabetic WCRHs, and the pale centers of many WCRHs in diabetic retinopathy may be platelet-fibrin aggregates.