Ophthalmologic opinion has been somewhat divided as to whether retinal changes typical of diabetes mellitus are manifestations of the disease itself or are due to alterations of the blood vessels in the retina or to abnormalities of blood pressure caused by the disease. If the latter is true, obviously conditions other than diabetes may cause similar retinal changes. Hence the problem is one of both clinical and theoretic interest.
General opinion favors the view that the ophthalmic changes are secondary to vascular changes. A particularly illuminating discussion is found in a symposium on diabetic retinitis in which Downey,1 discussing the subject from the point of view of the ophthalmologist, stated that most textbooks deal with diabetic retinitis in a very dogmatic way. In referring to the recent studies by Wagener and Wilder and by Benedict, he brought up the question whether diabetic retinitis as distinct from arteriosclerotic retinitis actually