What is diabetic retinopathy?
Chronic high blood sugar can damage the small blood vessels that nourish the retina, which is the nerve tissue in the back of the eye that collects light for vision. Diabetic retinopathy is when blood vessels in the retina swell, leak or close off. When fluid leaks out of the vessels, it sometimes collects in the retina. Swelling of the retina in the center of vision is called macular edema. Macular edema is the most common reason people with diabetes lose their vision. When blood vessels in the retina close off, nutrients may no longer reach parts of the retina, stimulating abnormal new blood vessels to grow on the surface of the retina. This is called proliferative diabetic retinopathy. These fragile vessels are not able to nourish the retina and instead can cause severe bleeding and scarring.