Studies on Diabetic Retinopathy* *From the Wilmer Ophthalmological Institute of the Johns Hopkins University and Hospital and the Division of Ophthalmology of the Sinai Hospital of Baltimore. These studies were aided in part by Grant No. B-2198, National Institute of Neurological Diseases and Blindness, U.S.P.H.S., Bethesda, Maryland. Presented in part at the annual meeting of the American Diabetic Association, New York, June, 1961.