Figure 1. Receiver operating characteristic curves of main effective Pentacam parameters to detect unilateral subclinical keratoconus (a), bilateral subclinical keratoconus (b) and clinical keratoconus (c) D: Overall deviation, EA: Anterior elevation at the thinnest point, EP: Posterior elevation at the thinnest point, PPI: Pachymetric progression index, IVA: Index of vertical asymmetry, KI: Keratoconus index, IHD: Index of height decentration.