Corticosteroids are very potent anti-inflammatory agents that can block several pathological processes which are thought to be involved in the development of macular edema in several ways: inhibiting the synthesis of VEGF, prostaglandins, and many proinflammatory cytokines, reducing fibrin deposition, preventing leukocyte migration, and stabilizing endothelial cell tight junctions [23]. The gene discussed is VEGFA; the disease is macular retinal edema.