The imbalance between endogenous angiogenic factors and angiogenic inhibitors is responsible for the formation of pathologic vessels.7 It has been shown that multiple angiogenic factors, such as VEGF, insulin-like growth factor, and erythropoietin, are implicated in the pathogenesis of DR and AMD.8,9 VEGF expression is upregulated in DR, ROP, AMD, and inflammation-associated corneal NV.10, –12 Alterations of these growth factors and their receptors have been identified in corneal NV, DR, ROP, and AMD in both experimental models and clinical studies.13, –15. The gene discussed is EPO; the disease is retinopathy of prematurity.