Diabetic retinopathy is the most common and serious eye-related complication of diabetes. It is a progressive disease that causes retinal swelling and destroys small blood vessels in the retina, eventually leading to vision problems. In its most advanced forms, known as "diabetic macular edema" and "proliferative retinopathy," it can cause moderate to severe vision loss and blindness. Nearly all people with type 1 diabetes show some symptoms of diabetic retinopathy usually after about 20 years of living with diabetes. With improved management of blood glucose the risks of this dreaded eye disease are decreasing. Those with type 2 diabetes are also at risk.

Over time, the disease progresses to its advanced or proliferative stage, and fragile new blood vessels grow along the retina. However, these fragile vessels can hemorrhage easily, and blood may leak into the retina and the clear, gel-like vitreous that fills inside of the eye. Unless quickly treated, this can result in spots, floaters, flashes, blurred vision, vision loss, and even temporary blindness. In later phases of the disease, continued abnormal vessel growth and the formation of scar tissue may cause serious problems such as retinal detachment and glaucoma, both of which can cause permanent blindness. Diabetic macular edema, which involves swelling in the retina that impairs vision, can occur at any stage of diabetic retinopathy. Treatment to prevent or reverse this condition remains a major unmet clinical need.  

Source: Juvenile Diabetes Research Foundation International