VEGFA and glaucoma: Hypoxia modulates expression of a number of genes.4,5,9-14 Among these, vascular endothelial growth factor (VEGF) gene is viewed as a critical mediator of endothelial sprouting at hypoxic sites.9-14 It has been proven that NO up-regulates expression of VEGF,12-14 which can be regulated by a variety of stimuli: hypoxia, cobaltous ion, nitric oxide (NO), growth factors, and cytokines.15 Hypoxia is regarded as the most potent VEGF regulator, and NO has recently drawn much attention as a regulator.16,17 Hypoxia and NO play important roles in pathogenesis of glaucoma.