[Diabetic retinopathy: pathogenesis, risk factors, clinical picture, classification]

Hyperglycemia is the main cause of diabetic complications. High glucose concentration acts directly on pericytes, endothelial cells and basal membrane of small vessels. Non-enzymatic reaction between glucose and proteins gives a substance called AGE (Advanced Glycosylation End Products). This AGE reacts with proteins, lipids, nucleic acids, lymphocytes and macrophages, antioxidants producing microvascular changes related to atherogenesis the high glucose level triggers formation and accumulation of sorbitol and galacticol causing alteration of cell membrane. These changes in vessel walls added to rheologic and hemostatic changes give rise to microthrombosis, ischemia and finally neovascular formation.