Diabetic retinopathy I. The course of retinopathy in insulin-treated diabetics. A one year epidemiological cohort study of diabetes mellitus. The Island of Falster, Denmark.

The course of diabetic retinopathy was investigated in 215 out of 227 insulin-treated diabetics in a one year epidemiological cohort study. Twelve diabetics, all with an onset age greater than or equal to 30 years, could not be re-examined due to deaths in 11 diabetics and deny in 1 diabetic. At the one year follow-up no change (P greater than 0.10) occurred in the prevalence of background retinopathy (50.0% vs 51.6%) or of proliferative retinopathy (16.3% vs 18.6%). The one year incidence of newly developed background retinopathy was 3.7% and of deteriorated retinopathy 10.7%. Newly developed proliferative retinopathy was found in 2.3% of the diabetics after one year. Deterioration of pre-existing background retinopathy developed most frequently among diabetics with a diabetes duration above 10 years. Deterioration of both background retinopathy and proliferative retinopathy showed a sudden onset in some diabetics. Partial sight and legal blindness caused by diabetic retinopathy developed in 3.7% of the diabetics, respectively.