Anterior Elevation Changes Following Corneal Crosslinking for Keratoconus

ABSTRACT

PURPOSE: To report the results according to anterior elevation changes following corneal crosslinking (CXL) treatment for keratoconus. METHODS: The present retrospective study included 14 patients (15 eyes) with progressive keratoconus who underwent CXL with a follow-up of 12 months. Patients were classified into 2 groups according to pre and postoperative anterior elevation difference maps. On the preoperative anterior elevation map, distances from maximum anterior elevation to pupil center were compared between the 2 groups. The outcome of best correct visual acuity (BCVA), maximum keratometry and parameters of corneal topography were compared between the 2 groups before CXL as well as 6 and 12 months after CXL. RESULTS: The anterior elevation changes were classified as group 1 (-7.88 +/- 10.53 micrometer) or group 2 (8.71 +/- 5.99 micrometer) (p = 0.001). The preoperative corneal topography of eyes observed in group 1 (0.19 +/- 0.13 mm) had shorter mean distances from maximum anterior elevation to pupil center than eyes in group 2 (0.47 +/- 0.23 mm) (p = 0.018). BCVA (log MAR) improved from 0.68 +/- 0.78 to 0.57 +/- 0.81 (p = 0.115) 12 months after CXL in group 1 and decreased from 0.51 +/- 0.34 to 0.56 +/- 0.38 (p = 0.109) 12 months after CXL in group 2. The maximum keratometry decreased from 63.01 +/- 19.07D to 58.95 +/- 16.32D (p = 0.017) in group 1 and increased from 60.70 +/- 9.46D to 61.29 +/- 7.51D (p = 0.674) in group 2. CONCLUSIONS: Clinical and optical effects improved postoperatively in group 1, and were stabilized in group 2. The preoperative distance from maximum anterior elevation to pupil center and the anterior elevation changes after CXL were factors in predicting the CXL outcome.