People with diabetes can develop a disease in their eyes called diabetic retinopathy.  Diabetic retinopathy is a leading cause of preventable vision loss in people between 20-60 years of age.  This occurs when high blood sugar damages the blood vessels of the retina, which is the lining over the back of the eye housing the specialized “light-sensing” cells.  Damage to the blood vessels causes leakage and inappropriate delivery of nutrients and oxygen to the retina, which can lead to vision loss.