Since transforming growth factor-beta (TGFβ) expression in the sclera is altered by the myopia induction26,27 and the TGFβ-SMAD pathway regulates collagen expressions28–31, we hypothesized that SMAD might be involved in the normalization of abnormal scleral collagen gene expression by 4-PBA. This evidence concerns the gene TGFB1 and myopia.