Keratoconus is a common ocular disorder that causes progressive corneal thinning and is the leading indication for corneal transplantation. Central corneal thickness (CCT) is a highly heritable characteristic that is associated with keratoconus. In this two-stage genome-wide association study (GWAS) of CCT, we identified a locus for CCT, namely STON2 rs2371597 (P = 2.32 × 10-13), and confirmed a significant association between STON2 rs2371597 and keratoconus development (P = 0.041). Additionally, strong STON2 expression was observed in mouse corneal epithelial basal cells. We also identified SMAD3 rs12913547 as a susceptibility locus for keratoconus development using predictive analysis with IBM's Watson question answering computer system (P = 0.001). Further GWAS analyses combined with Watson could effectively reveal detailed pathways underlying keratoconus development.