Impaired color vision associated with diabetic retinopathy: Early Treatment Diabetic Retinopathy Study Report No. 15.

PURPOSE To report color vision abnormalities associated with diabetic retinopathy. METHODS Color vision function was measured at baseline in 2,701 patients enrolled in the Early Treatment Diabetic Retinopathy Study, a randomized trial investigating photocoagulation and aspirin in the treatment of diabetic retinopathy. Hue discrimination was measured by the Farnsworth-Munsell 100-Hue test, and errors in color vision were reported as the square root of the total 100-Hue (SQRT 100-Hue) score. RESULTS Approximately 50% of the Early Treatment Diabetic Retinopathy Study population had color vision scores (SQRT 100-Hue score) worse than 95% of the normal population reported by Verriest and associates. The factors most strongly associated with impaired hue discrimination were macular edema severity, age, and presence of new vessels. A tritan-like defect was prominent and increased in magnitude with increasing severity of macular edema. However, many patients had color discrimination impairment without macular edema. CONCLUSIONS Impaired color vision is a common observation among participants enrolled in the Early Treatment Diabetic Retinopathy Study. Compared with published data on normal subjects, approximately 50% of the patients in the Early Treatment Diabetic Retinopathy Study had abnormal hue discrimination. Macular edema severity, age, and the presence of new vessels were the factors most strongly associated with impaired color discrimination. A tritan-like defect was prominent and increased in magnitude with increasing severity of macular edema. Impaired color vision should be considered in the evaluation and counseling of patients with diabetic retinopathy.