Diabetic retinopathy occurs when diabetes damages the tiny blood vessels in the retina. At this point, most people do not notice any changes in their vision. Some people develop a condition called macular edema. It occurs when the blood vessels leak fluid and lipids onto the macula, (The central part of the retina that lets us see in detail). The fluid makes the macula swell, thus blurring the vision. As the disease progresses, it enters its advanced, or proliferative stage. Fragile, new blood vessels grow along retina and the clear, gel-like vitreous that fills the inside of the eye. Without timely treatment, these new blood vessels can bleed, cloud vision and destroy the retina.