Choroidal thickness analysis in keratoconus patients

Abstract

Objective. To determine and compare choroidal thickness (CT) in keratoconus (KC) patients using Enhanced Depth Imaging (EDI) OCT. Methods. A comparative cross-sectional study including 26 patients with KC and 26 healthy controls assessed with Pentacam and EDI-OCT. CT was measured manually with the Caliper function at thirteen locations at 500 µm regular intervals. Results. The average CT in T6 was 253.96 ± 88.95 μm in the KC group, and of 309.39 ± 94.11 μm in the control group (p <0.041). No significant differences in mean CT were observed in the rest of the points, including the subfoveal CT (M), 351.48 ± 106.3 vs 365.35 ± 114.6 μm, (p = 0.66). No correlation was observed between the mean subfoveal CT (M), the mean CT in the KC group, and the values of K1 (p = 0.977 and p = 0.498 respectively), K2 (p = 0.450 and p = 0.656), corneal asphericity (Q ) (p = 0.986 and p = 0.902), minimal pachymetry (Pachy) (p = 0.408 and p = 0.688), keratoconus index (KI) (p = 0.601 and p = 0.217), vertical asymmetry index (VAT) (p = 0.296 and p = 0.523), staging of KC (TKC) (p = 0.549 and p = 0.08) and corneal apex morphology. Conclusion. Significant lower CT was found in the KC group in T6 (3000 μm temporal to the fovea). No significant difference of CT values in KC patients and healthy subjects was found in the other twelve measurement locations.We found no association between the refractive and keratometric indexes obtained by corneal topography and subfoveal CT.