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Efficacy of Epithelium-Off and Epithelium-On Corneal Collagen Cross-Linking in Pediatric Keratoconus

Eraslan, Muhsin M.D.; Toker, Ebru M.D.; Cerman, Eren M.D., F.E.B.Ophth.; Ozarslan, Deniz M.D.

doi: 10.1097/ICL.0000000000000255

Objectives: To evaluate the efficacy of riboflavin/ultraviolet A epithelium-off (epi-off) and epithelium-on (epi-on) corneal collagen cross-linking (CXL) in progressive pediatric keratoconus.

Methods: Thirty-six eyes of 27 patients aged 18 years or younger (12–18 years) diagnosed with progressive keratoconus and treated with epi-off (n=18 eyes) or epi-on (n=18 eyes) CXL were included in this study. All patients were followed up for 24 months postoperatively.

Results: At 24-month follow-up, the mean corrected distance visual acuity (CDVA) improved from 0.24±0.17 to 0.17±0.11 logMAR in the epi-off group (P=0.032). In the epi-on group, CDVA improved from 0.33±0.23 to 0.26±0.20 logMAR (P=0.012), but the improvement was not significantly different between groups (P>0.05). In the epi-off group, all mean K values improved: K1 (Δ=−0.63 D, P=0.024), K2 (Δ=−0.73 D, P=0.008), and Kmax (Δ=−1.4 D, P=0.035), whereas in the epi-on group, Kmax and K2 did not change significantly and K1 (Δ=0.68 D, P=0.029) significantly worsened. Postoperative mild corneal haze occurred in 5 eyes (28%) in the epi-off group. No postoperative complications were observed in the epi-on group. In 94.4% of the epi-off group, keratoconus regressed (44.4%) or stabilized (50.0%), whereas in the epi-on group, only 66.6% regressed (33.3%) or stabilized (33.3%), and the difference was significant (P=0.038).

Conclusions: The efficacy of the epi-on procedure in terms of its ability to halt keratoconus progression appears to be 0.70 of the efficacy of epi-off CXL.

Department of Ophthalmology, Marmara University School of Medicine, Istanbul, Turkey.

Address correspondence to Ebru Toker, M.D., Goz Hastaliklari Anabilim, Dali Departmani Fevzi, Marmara Universitesi Pendik, Egitim Arastirma Hastanesi, Cakmak Mah, Muhsin Yazicioglu Cad, No: 10 Ust Kaynarca, Pendik, 34890 Istanbul; e-mail:

The authors have no funding or conflicts of interest to disclose.

English-language editing of this manuscript was provided by Journal Prep. Design of the study (M.E., E.T.); Conduct of the study (M.E., D.O.), collection (M.E., D.O., E.T.), management (M.E., E.T.), analysis and interpretation of the data (M.E., E.T., E.C.), preparation (M.E., E.C., D.O., E.T.), review (M.E., E.C., E.T.).

Accepted January 11, 2016

© 2017 Contact Lens Association of Ophthalmologists, Inc.