Role of corneal epithelial thickness mapping in the evaluation of keratoconus

Purpose: To investigate the corneal epithelial thickness profiles in patients with a confirmed diagnosis of stable and progressive keratoconus. Setting: Studio Italiano di Oftalmologia, Rome, Italy. Design: Observational study. Methods: 86 patients with either stable (n=52) or progressive (n=34) keratoconus and 182 healthy controls were enrolled in the study. Disease progression was confirmed by repeated corneal topographies over 1 year follow-up before inclusion in the study. All subjects had full corneal and epithelial thickness mapping taken by spectral domain optical coherence tomography (SD-OCT). The full corneal mapping was investigated by evaluating the central corneal thickness, the thinnest point, the superonasal-inferotemporal thickness difference and the minimum-median thickness difference. The epithelial mapping was investigated by assessing the 2mm central thickness, the inferior paracentral (2-5 mm) thickness, and the minimum-maximum thickness difference. Results: No significant differences in full corneal mapping were found between stable and progressive keratoconic eyes. Of note, the inferior paracentral region of the corneal epithelium was significantly thinner in progressive (50 ± 3 ?m) than stable (53 ± 4 ?m) keratoconus (P < 0.001). Conclusions: The SD-OCT corneal epithelial mapping was valuable for detecting local thickness changes in eyes with keratoconus. Monitoring the corneal epithelial changes across the inferior area in patients with keratoconus could be worthy for assessing disease progression.