VSX1 and keratoconus: Table 2 summarizes the information regarding VSX1. It has been shown to play a significant role in craniofacial and ocular development by regulating cone opsin expression during early stages of eye formation [53]. Although first linked to posterior polymorphous corneal dystrophy (PPCD), this gene has also been associated with KC, mainly through its role in eye development and its impact on stromal and retinal thinning [54,55,56].