Diabetic retinopathy in African Americans with type 1 diabetes: The New Jersey 725: I. Methodology, population, frequency of retinopathy, and visual impairment.

OBJECTIVE To determine the frequency and severity of diabetic retinopathy, as well as associated visual impairment, among African Americans with type 1 diabetes. METHODS A total of 725 African Americans with type 1 diabetes were enrolled in the study (The New Jersey 725). Clinical evaluations included structured clinical interview, ocular examination, stereoscopic fundus photography, and blood pressure measurements. Severity of retinopathy was determined via masked grading of fundus photographs. Biological evaluations included blood and urine assays. RESULTS Of the 725 patients, 463 (63.9%) presented with any diabetic retinopathy and 137 (18.9%) with proliferative diabetic retinopathy. The frequency and severity of retinopathy were both significantly associated with older age at examination. Visual impairment (visual acuity in the better eye < or =20/40) was present in 79 (11.0%) and legal blindness in 22 (3.1%) of the patients. Diabetic retinopathy was responsible for 90.9% of the blindness. Frequency of visual impairment was significantly associated with older age and female sex, and only weakly with lower education. CONCLUSIONS Diabetic retinopathy in African Americans with type 1 diabetes is common, being found in almost two thirds of the patients studied. Its frequency and severity increase with age. Visual impairment is common, increasing with age and duration of diabetes and is more frequent in women than in men.