The Wisconsin Epidemiologic Study of Diabetic Retinopathy. VII. Diabetic nonproliferative retinal lesions.

The prevalences of hard exudates, soft exudates, intraretinal microvascular abnormalities (IRMAs), and venous beading and their relationships to demographic and other characteristics were examined in a population-based study in southern Wisconsin. For participants whose age at diagnosis was less than 30 years and who were taking insulin (N = 996), hard exudates were found in 24.2%, soft exudates in 15.3%, IRMAs in 16.5%, and venous beading in 7.0% of the population. For participants whose age at diagnosis was 30 years or older and who were taking insulin (N = 674), hard exudates were found in 28.3%, soft exudates in 15.5%, IRMAs in 8.8%, and venous beading in 3.2%. For older-onset persons not taking insulin (N = 696), hard exudates were found in 9.4%, soft exudates in 5.4%, IRMAs in 2.6%, and venous beading in 0.9% of the population. The severities of the lesions were found to be consistently associated with longer duration of diabetes in younger-onset persons and the presence of proteinuria in older-onset persons.