In the last decade, anti-angiogenic therapy, i.e., intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) agents, has been the standard of care for the treatment of neovascular eye diseases, particularly in age-related macular degeneration (AMD), diabetic retinopathy (DR) including diabetic macular edema (DME), and macular edema secondary to retinal vein occlusions (RVO). This evidence concerns the gene VEGFA and diabetic macular edema.