A 7bp intronic deletion was observed in cases but not controls in two of these reports[33, 43] and was significantly more frequent in cases compared to controls in another,[59] however, the remaining studies did not observe the variant.[45, 53, 63, 64] Given the contention surrounding the involvement of VSX1 and SOD1, and the few studies that assessed the remaining functional candidates, further analysis is required to determine if they contribute to keratoconus susceptibility and pathogenicity. Here, SOD1 is linked to keratoconus.