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 12months 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 4months. 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.