Numerous new studies indicate the main role of angiogenic growth factors on the development of proliferative diabetic retinopathy, and VEGF is considered to be the most important one [19], followed by erythropoietin, IGF-1, PDGF, etc. Intraocular synthesis of proangiogenic factors is in counterbalance with the production of antiangiogenic ones. This evidence concerns the gene EPO and proliferative diabetic retinopathy.