Using an in vitro system, we show that WT acini ciliate upon ADM, as previously reported in vivo, express Ihh and upregulate the Hh target gene Ptch1. We show that acini from KC mice also assemble primary cilia upon ADM; however, the number of ciliated cells is significantly reduced and, consequently, the ability of these cells to respond to Hh signals is decreased. Here, PTCH1 is linked to keratoconus.