diabetic retinopathy

The retina at the back of the eye is lined with some of the body's tiniest, most delicate blood vessels — and years of high blood sugar slowly corrode them like rust eating thin pipes. In diabetic retinopathy these vessels leak, swell, and clog, threatening the very tissue that turns light into sight.

Diabetic retinopathy is a microvascular complication in which chronic hyperglycemia damages the small retinal vessels. In the early (non-proliferative) stage, weakened vessels form bulges (microaneurysms), leak fluid and blood, and may cause swelling of the central retina (macular edema). In the advanced (proliferative) stage, blocked vessels starve the retina of oxygen, which triggers the growth of fragile new vessels that can bleed into the eye or pull the retina away.

It is a leading cause of blindness in working-age adults, yet it is often silent until vision is already threatened, which is why people with diabetes need regular dilated eye exams. The most important defenses are good control of blood glucose and blood pressure over the long term. When the disease is advanced, treatments such as laser photocoagulation, injections of anti-VEGF drugs, or surgery can preserve sight, but damage already done is hard to undo.