Over time, too much sugar in your blood can block tiny blood vessels of the retina, cutting off its blood supply.
As a result, new vessels grow, but they are fragile and eventually leaks leading to diabetic retinopathy.
There are two types of diabetic retinopathy:
Early diabetic retinopathy. In this more common form — called nonproliferative diabetic retinopathy (NPDR) — new blood vessels aren't growing (proliferating).
Advanced diabetic retinopathy-more severe type, known as proliferative diabetic retinopathy in which newly formed blood vessels leak.