Thanks to animal models, the molecular mediators implicated in this process have been partially identified, including vasoactive intestinal peptide, dopamine, retinoic acid, glucagon, insulin, γ-aminobutyric acid, transforming growth factor, basic fibroblast growth factor, and insulin-like growth factor-1.27–34 As a complex disorder with environmental and genetic risk factors involving many inheritance modes, myopia has been associated with 261 genetic disorders.35 Here, GCG is linked to myopia.