Anyone with diabetes is at risk for developing diabetic retinopathy. The longer a person has diabetes, the greater their chance of developing diabetic retinopathy. It is the leading cause of blindness in working-aged adults in the United States. Diabetes damages the retina in two ways. The first, known as non-proliferative diabetic retinopathy, occurs when the blood vessels of the retina begin to bleed or leak fluid. This results in retinal swelling (macular edema), small hemorrhages, and the formation of deposits known as exudates.
The second way that diabetes damages the retina is known as proliferative diabetic retinopathy. This is a more severe type of retinal damage. It occurs when blood vessels in the retina or optic nerve become blocked, consequently starving the retina of necessary nutrients. In response, the retina grows new blood vessels (neovascularization). Unfortunately these new vessels are abnormal, causing bleeding or formation of scar tissue.