VEGFA and retinopathy of prematurity: There is a two-phase hypothesis of ROP [5], in first phase, delayed retinal vascular development leads to a peripheral avascular area of the retina, and in second phase, angiogenesis can happen at the junction of avascularized and vascularized retina as a result of pathological compensatory mechanism, this process is considered to be attributed to the aberrant changes of oxygen tension and vascular endothelial growth factor (VEGF) level.