VEGFA and edema: VEGF promotes endothelial cell differentiation, proliferation and migration by activating its tyrosine kinase receptors VEGFR1 and VEGFR 2, changing the extracellular matrix and breaking down the inner endothelial blood-retinal barrier, eventually causing endothelial cell injury, angiogenesis, retinal vascular permeability, retinal edema, visual impairment, and complete blindness in severe cases29.