Accelerated Corneal Collagen Cross-Linking in Thin Keratoconic Corneas

Abstract

PURPOSE: To report the outcomes of accelerated corneal collagen cross-linking in patients with thin corneas (minimum corneal thickness < 400 mu m). METHODS: Thirty-four eyes of 34 patients with a minimum corneal thickness less than 400 mu m were included. All patients underwent accelerated corneal collagen cross-linking (irradiance power of 30 mW/cm(2) at 3 minutes with a total surface dose of 5.4 J/cm(2)). Uncorrected (UDVA) and corrected distance visual acuity (CDVA), manifest refraction (diopters [D]), and topography were evaluated at baseline and at the 1-, 6-, and 12-month follow-up visit. Endothelial cell density (cells/mm(2)) was calculated preoperatively and postoperatively at 12 months. The corneal stromal demarcation line was measured using anterior segment optical coherence tomography at 1 month postoperatively. RESULTS: The mean age of all patients (14 women and 20 men) was 23.08 +/- 3.90 years (range: 16 to 29 years). UDVA and CDVA increased but not significantly. UDVA improved from 0.67 +/- 0.32 (20/93 +/- 20/41 Snellen) to 0.56 +/- 0.28 logMAR (20/72 +/- 20/38 Snellen) (P = .033) and CDVA improved from 0.49 +/- 0.19 (20/61 +/- 20/30 Snellen) to 0.42 +/- 0.19 logMAR (20/52 +/- 20/30 Snellen) (P = .009) at the last follow-up visit. The mean spherical and cylindrical refractions did not significantly change (P = .100 and 0.139, respectively). At the last follow-up visit, the flat keratometry decreased from 47.40 +/- 2.52 to 46.95 +/- 2.48 D, steep keratometry decreased from 51.04 +/- 3.71 to 50.62 +/- 3.57 D, and apex keratometry decreased from 57.58 +/- 4.49 to 56.26 +/- 4.47 D (P = .001, = .0019, = .001, respectively) from baseline. The mean endothelial cell density changed from 2,726.02 +/- 230.21 to 2,714.58 +/- 218.26 cells/mm(2) at 12 months postoperatively (P =. 086). CONCLUSION: The results of this study revealed that accelerated corneal collagen cross-linking stabilized the progression of keratoconus without a significant endothelial cell density loss during the 12 months of follow-up.