Further studies in other ethnic populations with large numbers of patients and well-defined diagnostic criteria should thus be performed to elucidate whether the p53 intron 3 insertion or this insertion combined with a codon 72 polymorphism is a genetic risk factor for POAG, especially NTG, because the intron 3 insertion polymorphism seems to be a rare event in the Japanese population. This evidence concerns the gene OPA1 and open-angle glaucoma.