This could be relevant because an epidemiological study written by Cappuccio et al underlined that TT genotype is more frequent in Caucasian subjects compared to Asian subjects [36] and a previous study by Cahill et al. [30] on subjects from US revealed that hyperhomocysteinemia but not TT genotype of MTHFR was a risk factor for RVO. Here, MTHFR is linked to hyperhomocysteinemia.