<qa>  What is the main cause of retinopathy?Diabetic retinopathy is the leading disease that causes acquired vision loss after 20 by making diabetic macular edema and neovascularization. In recent young generation, as prevalence of type 2 diabetes is growing, the burden of sight-threatening retinopathy is increasing on trend.1 Pathologically, angiogenesis is a main cause that destroys the structure of the eye and induces the visual function disorder as VEGF playing an important role in increasing the migration and proliferation of endothelial cells and increasing the permeability of the blood vessels.2,3 VEGF is made from the endothelial cells of retinal tissue, perivascular cells, pigment endothelial cells by hypoxia. And hypoxic condition of intraocular tissues is a key regulator of intra ocular angiogenesis by VEGF, the balance between VEGF and angiogenesis inhibitors determines the neovascular proliferation in diabetic retinopathy.4 VEGF is also inducing the expression of cell-to-cell contact molecule intracellular adhesion molecule-1, ICM-1 and the adhesion of leukocytes to help the inflammatory response5, as mediator which destroys the blood retinal barrier, affecting the protein of tight junctions, making a microaneurysm and increasing permeability of capillary, that makes the liquid leakage and macular edema.5,6 Microanuerysm is the earliest clinical manifestations, the saccular local lesion that perivascular cells protruding in damaged areas on the capillary wall. According to Stitt AW et al9, diabetic microaneurysm is non-functioning extrusion of the vascular system from the deep part of inner retinal capillary plexus. 