Medical management of diabetic retinopathy: an overview.

Diabetes mellitus is a global health problem affecting 366 million people worldwide and its prevalence is growing rapidly. Diabetic eye disease is present in up to 25% of diabetic subjects. Diabetic retinopathy is a chronic complication of diabetes that can result in blindness. Generally, there are two stages of diabetic retinopathy, non-proliferative and proliferative. The longer a person has diabetes and the poorer metabolic control, the higher the chance of developing diabetic retinopathy. The majority of people with type 2 diabetes will ultimately develop diabetic retinopathy.  Multifactorial therapy targeted to lifestyle modification and optional glycemic control reduces the risk. However, diabetic retinopathy develops or progresses with time.  Primary (preventive) strategies include glycemic, lipid, and blood pressure control.  Glycemic control effectively reduces the incidence of diabetic retinopathy. In additional, its effect on progression of diabetic retinopathy has been demonstrated in randomized clinical trials.  Furthermore, tight control of blood pressure significantly reduces the progression of retinopathy and visual loss. However, the Action to Control Cardiovascular Risk in Diabetes (ACCORD) Eye Study Group has shown that intensive blood pressure control has no beneficial effect on reducing the rate of diabetic retinopathy in subjects with type 2 diabetes.  Elevated serum lipids and dyslipidemias are associated with a higher risk of diabetic retinopathy. The beneficial effects of lipid-lowering agents on the progression of retinopathy have been reported. Intensive combination therapy for dyslipidemia has been shown to effectively reduce the rate of progression of diabetic retinopathy in type 2 diabetes.  Secondary strategies are focused on various pathophysiologic approaches such as blockade of the renin angiotensin system (RAS), anti-vascular endothelial growth factor agents, somatostatin analogues, protein kinase inhibitors, and anti-inflammatory agents.  The purpose of the current overview is to look into the medical management of diabetic retinopathy, and to explore the primary (preventive) measures as well as secondary strategies proposed to be effective in its medical management.