Diabetic retinopathy is a complication of diabetes and a leading cause of blindness.  "Retinopathy" is the medical term for damage to the tiny blood vessels (capillaries) that nourish the retina, the tissue at the back of the eye that captures light and relays information to your brain. These blood vessels are often affected by the high blood sugar levels associated with diabetes.  Nearly half of people with known diabetes have some degree of diabetic retinopathy.  Initially, most people with diabetic retinopathy experience only mild vision problems. But the condition can worsen and threaten your vision.