THY1 and keratoconus: KC and DN fibroblasts were cultured in low glucose serum-free media (LGSF) for 2 weeks (Fig. 1A) to induce keratocyte-like features.22 In this 14-day LGSF culture system, DN and KC keratocytes displayed: (1) similar morphologies (Supplementary Fig. S1); (2) minimal fibroblastic activation as gauged by low mesenchymal THY-1 marker expression26 (Fig. 1B); and (3) comparable keratocyte qualities with respect to expression of the keratocyte marker, keratocan (Fig. 1C)27 and ALDH3A1, a “corneal crystallin,”28 (Figs. 1D, 1E; Supplementary Fig. S2).