Diabetic retinopathy II. The course of retinopathy in diabetics treated with oral hypoglycaemic agents and diet regime alone. A one year epidemiological cohort study of diabetes mellitus. The Island of Falster, Denmark.

: The course of diabetic retinopathy was investigated in 273 out of 306 diabetics treated with oral hypoglycaemic agents (OHA) and 60 out of 72 diet-treated diabetics in an epidemiological cohort study in a period of one year. In the OHA-treated diabetics the allover prevalence of retinopathy did not change (P greater than 0.10) after one year (125/306 = 40.9% vs 122/273 = 44.7%). The one year incidence of new and deteriorated background was 3.7% and 6.6%, respectively. New cases of proliferative retinopathy developed in 1.1% and a worsening of pre-existing proliferative retinopathy in 1.8%. Among diabetics with pre-existing background retinopathy (n = 93) progressed, and 2% became proliferative. A worsening of retinopathy occurred more frequently (P less than 0.01) in diabetics with an onset age less than 60 years and with a duration greater than 5 years. The incidence of partial sight and legal blindness due to retinopathy was 2.2% and 1.9%, respectively, among all diabetics. Among diet-treated diabetics, 2 diabetics (3.3%) developed background retinopathy. None with pre-existing background retinopathy showed any deterioration.