The back of the eye, or retina, has nerve tissue that enables us to see. In Type 2 diabetes high blood sugar levels cause damage to nerve tissue, as well as the blood vessels feeding the tissue. Such damage can thin the retina, which can lead to loss of vision. Until recently diabetic retinopathy, a leading cause of blindness has been thought of as primarily a disease of the blood vessels in the back of the eye, or retina. Treatment has been aimed at coagulating weak blood vessels and removing blood from the inside of the eye. New studies have found nerve damage in the eyes takes place before changes are seen in the blood vessels. Finding nerve damage and treating it early could be a boon to people diagnosed with Type 2 diabetes in danger of losing their sight.