Prevalence of diabetic retinopathy and distribution of its severity among patients of a university clinic of diabetes in Osaka.

We have been following longitudinal changes of diabetic retinopathy by periodic fundoscopy in patients at our out-patient clinic for diabetes mellitus. In this study, we reviewed the prevalence of diabetic retinopathy and the distribution of its severities. Funduscopic examinations for retinopathy were performed on 242 patients. They ranged in age from 13 to 84 years (52.9 +/- 0.9, mean +/- s.e.). Duration of diabetes ranged from 1 to 31 years (10.7 +/- 0.4). Forty patients were treated with diet alone, 112 with oral hypoglycemic agents and 90 with insulin administration. No retinopathy was found in 83 patients (34%), background retinopathy in 113 (47%), preproliferative retinopathy in 24 (10%) and proliferative retinopathy in 17 (7%). Five patients (2%) were blind. Twenty-seven patients (60%) of 45 with a less than 5-year duration of diabetes were apparently without retinopathy, while the incidence of proliferative retinopathy increased in proportion to the duration. Fasting plasma glucose and glycosylated hemoglobin levels were higher in the patients with proliferative retinopathy than in any other group. All of the blind patients had a long history of untreated diabetes. Whether diabetic control assessed by glycosylated hemoglobin influences the progression of retinopathy could not be demonstrated by a 2-year observation. Further analysis based on a longer duration is needed in this respect.