Rambam Physician Discovers New Cause of Vision Loss in Diabetics

Diabetes is the leading cause of new vision loss in working-age adults (20-60 years old) worldwide. Israel is at the cutting edge in diabetes research, with the third highest mortality rate from diabetes among countries in the Organization for Economic Cooperation and Development (OECD), especially in the Israeli Arab population. Professor Naim Shehadeh, Director of Rambam’s Diabetes, Endocrinology and Metabolism Institute and President of the Israel Diabetes Association, hypothesized that although hyperglycemia (abnormally high blood glucose levels) is the major known risk factor for vision complications in diabetics, exposure to sun-light may also be important. Common diabetic symptoms include blurred vision, early onset of cataracts, and retinal damage that can even lead to blindness.

Many visual problems in diabetics are caused by changes in the lens (cataract) or as a result of damage and reduced function in the light-sensitive lining (retina) at the back of the eye (diabetic retinopathy) followed by changes in the blood retinal barrier due to leaky small blood vessels, retinal swelling, and scarring. Since controlling hyperglycemia slows down but does not prevent these visual problems and their progression, the assumption was that other factors must contribute to diabetic cataracts and retinopathy.

Since human eyes are exposed to a wide spectrum of light during the day, Professor Shehadeh and his Technion team hypothesized that exposure to sunlight may play an important role in the development of eye damage in diabetic patients. They exposed diabetic rats to different wavelengths of light from the visible sunlight spectrum and identified the harmful light. The next step was to develop an optic filter that would block and protect the eyes from those wavelengths. Results showed that using these special optic filter glasses significantly decreased light exposure by filtering out the short wavelengths (400–530 nm) thereby reducing eye damage in diabetic rats, indicating a possible benefit for both diabetic and non-diabetic patients.

Professor Shehadeh says the team felt driven, “we had nothing to offer diabetic patients with eye damage other than instructing them to try to control their blood glucose levels.” Human trials to test the effect of the optical filters will begin later this year. Prescription and non-prescription sunglasses with colored optic filters will be available in the spring for Israeli consumers. Future goals include the development of colorless filters to offer the same protection in glass, windows of buildings and vehicles… and wherever else such filters could slow or prevent vision loss in diabetics and perhaps non-diabetics.