This is a class of medicines that are designed to combat neovascularization inside the eye and decrease blood vessel leakage. They are usually used for treating problems like macular edema, caused by wet macular degeneration, though occasionally they are used for treating swelling from other sources such as diabetic retinopathy or central retinal vein occlusion. These medicines work by decreasing leakage of fluid across abnormal blood vessels in the retina. The original anti-VEGF medication used was the injection medicine Avastin which was originally formulated for combating colon cancer. Lucentis and Eylea are newer anti-VEGF medications that may be more effective with less systemic side effects, but are quite costly when compared to Avastin. Refer to the entries on VEGF and neovascularization to better understand how these medications work.