PAX6 and aniridia: Furthermore, as previously mentioned, in a mouse model of trephine-mediated corneal injury, exogenous topical application of SHH facilitated corneal wound healing, but only in wild type animals (healthy corneas) and not in PAX-6+/− animals (a murine model of aniridia), suggesting that pharmacological modulation of Hedgehog signaling may promote wound healing in some corneal diseases, such as those resulting from injury or infection, but not in human aniridia (a genetic condition secondary to PAX-6 mutation) [48].