The American multicenter Age-related eye disease study (AREDS) showed that supplementation with zinc and antioxidants (vitamins C, E and beta carotene) reduced progression of intermediate and late AMD by 25% and vision loss by 19%, but did not slow progression of early AMD. However, it did not slow the progression of early AMD. Recent studies have shown that neovascularization is mediated by a number of vascular growth factors, mainly vascular endothelial growth factor (VEGF). There are many potential sites of action for drugs to inhibit angiogenesis, and the ideal drug would act selectively on neovascular tissue with few side effects, but current drugs fail to meet this criterion, and although many antineovascular drugs have been identified in laboratory studies, only a few have entered clinical trials. Pegaptanib (Macugen) is an anti-VEGF aptamer that specifically inhibits the activity of extracellular VEGF. The U.S. Food and Drug Administration (FDA) approved Macugen for clinical use in 2004. Multicenter clinical trials have confirmed that Macugen has a delaying effect on vision loss in patients with exudative AMD. Ranibizumab (Lucentis), a recombinant active fragment of a VEGF monoclonal antibody, was approved by the FDA on June 30, 2006 for the treatment of wet AMD and has been shown to improve visual acuity. Bevacizumab (trade name Avastin), which received FDA approval in February 2004, is a recombinant human monoclonal antibody that inhibits neovascularization through inhibition of VEGF and is primarily used in the first-line treatment of advanced colon and rectal cancer, with many recent studies attempting to use it in the treatment of choroidal neovascularization secondary to age-related macular degeneration (AMD) .