Comparison of transepithelial corneal collagen crosslinking with epithelium-off crosslinking in progressive keratoconus

Purpose. - To evaluate the safety and efficacy of transepithelial corneal collagen crosslinking (TE-CXL) as compared to epithelium-off crosslinking (epi-off CXL) in progressive keratoconus. Methods. - Records of keratoconus patients treated with TE-CXL or epi-off CXL were reviewed retrospectively. Patients were included if they had at least 12 months follow-up. Pre- and postoperative measurements of visual acuity, refractive errors, keratometry, corneal topography and pachymetry were assessed and compared. Results. - There was no statistically significant difference between two groups at baseline in terms of demographic, refractive and corneal parameters. Mean maximum cone apex curvature (apical K) increased from 51.62 +/- 5. Eighty-four diopters (D) to 53.70 +/- 5.49 D in the TE-CXL group (n = 17), and decreased from 52.02 +/- 4.07 D to 51.22 +/- 3.51 in the epi-off CXL group (n = 19) at the end of the follow-up period. The difference between two groups was statistically significant (P = 0.0002). An increase of >= 1D in apical K was observed in two of 19 eyes (11%) in the epi-off CXL group, and 11 of 17 eyes (65%) in TE-CXL group at the last follow-up visit, compared to baseline (P < 0.0001). Fourteen patients in the epi-off CXL group exhibited corneal edema that resolved without haze with topical corticosteroid treatment by 4 months. No postoperative corneal edema was observed in TE-CXL group. Conclusions. - Although it is safe and well tolerated, TE-CXL does not effectively halt the progression of keratoconus. Epi-off CXL appears to be effective in stopping progression and even improves corneal parameters. (C) 2014 Elsevier Masson SAS. All rights reserved.