Diabetic retinopathy in blacks. Diabetic eye disease, particularly diabetic retinopathy, is the leading cause of new cases of legal blindness in people 20-74 yr of age in the United States. The prevalence and rate of diabetes in this age-group are higher in Blacks than in Whites. The rate of blindness from diabetic eye disease is also higher in Blacks than in Whites. Severe macular edema, the most frequent cause of decreased vision in diabetic retinopathy, appears to be more common in Blacks. Risk factors for developing macular edema include poorly controlled hypertension, hyperglycemia, and duration of disease. The higher prevalence of hypertension in Blacks may contribute to the increased severity of diabetic retinopathy. Further evaluation is necessary to determine the influence of race on the severity of diabetic retinopathy. 