VSX2 and Anophthalmia: Several anophthalmia- or microphthalmia-causing genes have been identified to date and include, among others, paired box 6 (PAX6), orthodenticle homeobox 2 (OTX2), sex determining region Y-box 2 (SOX2), visual system homeobox 2 (VSX2), ventral anterior homeobox 1 (VAX1), and retina and anterior neural fold homeobox (RAX) [4-6].