ABSTRACT

To study the effect of corneal collagen cross-linking on conus curvature and corneal aberrations in keratoconus.

The medical records of thirty-seven eyes of 32 progressive keratoconus patients (17 male, 15 female, mean age: 22.13±4.64 years) who had undergone corneal cross-linking were evaluated retrospectively. The change in refractive errors, visual acuity on Snellen charts, average keratometry, conus curvature, and corneal aberrations calculated at 6.00 mm pupil size throughout the follow-up time were compared with paired t-test. The correlation of the change in best-corrected visual acuity and in uncorrected visual acuity with the change of the parameters which had statistically significant difference at 18 months was studied with Pearson’s correlation analysis.

The best-corrected visual acuity, uncorrected visual acuity, spherical and cylindrical error, average keratometry, conus curvature, vertical coma, total corneal aberrations, total higher order aberrations had statistically significant difference at 18 postoperative months (p=0.001). Spherical aberration (p=0.95) and horizontal coma (p=0.78) did not show statistically significant difference at the end of follow-up. The change in uncorrected visual acuity correlated with change in conus curvature (r=-0.420, p=0.01) and change in cylindrical refraction (r=0.453, p=0.005) at 18 months. The change in best-corrected visual acuity correlated with change in total corneal aberrations (r=-0.490, p=0.002), vertical coma (r=0.408, p=0.01), average keratometry (r=-0.386, p=0.02), conus curvature (r=-0.381, p=0.02), and total higher order aberrations (r=-0.326, p=0.05) at 18 months.

Corneal collagen cross-linking treatment applied to progressive keratoconus cases induces significant decrease in conus curvature, in total corneal aberrations, and in higher order aberrations, especially in vertical coma, and leads to a prominent visual acuity increase eventually.