Advances in the Medical Treatment of Diabetic Retinopathy

P roliferative diabetic retinopathy (PDR) remains the leading cause of blindness among working-age individuals in developed countries (1). Diabetic macular edema (DME), another important event that occurs in diabetic retinopathy, is more frequent in type 2 than type 1 diabetes (2). Whereas PDR is the most common sight-threatening lesion in type 1 diabetes, DME is the primary cause of poor visual acuity in type 2 diabetes. Because of the high prevalence of type 2 diabetes, DME is the main cause of visual impairment for diabetic patients (2). In addition, DME is almost invariably present when PDR is detected in type 2 diabetes (3). Neovascularization caused by severe hypoxia is the hallmark of PDR, whereas vascular leakage caused by the breakdown of the blood retinal barrier (BRB) is the main event involved in the pathogenesis of DME (4,5).