Introduction: The clinical use of intravitreal bevacizumab (IVB), a recombinant humanized monoclonal antibody that functions as an anti-vascular endothelial growth factor (anti-VEGF), has recently increased in patients with retinal ischemic diseases such as proliferative diabetic retinopathy (PDR). The gene discussed is VEGFA; the disease is proliferative diabetic retinopathy.