Patient with dissociation of corneal topography and epithelial mapping

A 21-year-old man was referred for refractive surgery evaluation. Spectacle dependence and poor visual quality in his left eye is his chief complaint. He cannot tolerate contact lenses (CLs). The corrected distance visual acuity (CDVA) was 20/20 in the right eye (-1.50 -2.00 × 180) and 20/30 in the left eye (-1.25 -1.50 × 170). The patient denied any history of ocular trauma, systemic disease, or medications. Corneal topography with different technologies revealed an inferior steepening in the left eye (Figure 1), whereas keratoconus indices from different strategies are within normal limits in both eyes (Supplemental Figures 1-4, http://links.lww.com/JRS/A496). Pachymetry maps from different devices present absolute values of thinnest point within normal ranges. Epithelial mapping revealed a localized thickening in the left eye (Supplemental Figures 5 and 6, http://links.lww.com/JRS/A496). Slitlamp showed a total clear cornea with no signs of abnormality. The patient presents no signs of blepharitis or dry-eye syndrome either. Intraocular pressure is 14 mm Hg in both eyes. The retina was normal, bilaterally. Considering the findings, what would be your main diagnostic hypothesis and, if any, which refractive surgery option would you consider for this patient?