Comparison of Results of Accelerated Corneal Cross-Linking With Hypo-Osmolar Riboflavin Solution Performed on Corneas Thicker and Thinner Than 400 μm.

PURPOSE: To evaluate the effect of accelerated corneal cross-linking (CXL) according to corneal thickness in keratoconus.

METHODS: Patients undergoing corneal CXL (9 mW/cm(2)) with hypo-osmolar riboflavin solution were included in this study. The patients were divided into 2 groups. Group 1 included patients with corneal thickness below 400 μm (50 eyes from 45 patients), and group 2 included patients with corneal thickness above 400 μm (50 eyes from 47 patients). Visual acuity (VA), refraction, topographic values, and higher-order aberrations were evaluated in the preoperative term and postoperatively at months 1, 3, and 6.

RESULTS: The improvements in VA were significant and similar in both groups [0.25/0.19 logMAR, P = 0.130]. In group 1, the rate of decrease in spherical refraction [0.85/0.27 diopters (D), P = 0.012] and maximum keratometry (Kmax, 2.49/0.68 D, P < 0.001) was significantly higher than that in group 2. The cylindrical change was similar (0.43/0.29 D P = 0.173). Corneal thinning was higher in group 2 (25/40.4 μm P < 0.001). Anterior elevation values decreased at higher rates in group 1 (3.73/0.24 μm P < 0.001); neither group showed a significant difference in posterior elevation (-0.14/-0.4 μm P > 0.05). In group 1, all aberration values except trefoil significantly decreased, whereas in group 2 none of the aberrations decreased except the total root mean square. All higher-order aberration values decreased at significantly higher rates in group 1 (P < 0.05).

CONCLUSIONS: In thin corneas, accelerated corneal CXL provides better anatomical changes; however, the improvement in VA is similar to that in thick corneas.