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Factors Influencing Progression of Keratoconus 2 Years After Corneal Collagen Cross-Linking in Pediatric Patients

Sarac, Ozge MD*; Caglayan, Mehtap MD*; Cakmak, Hasan Basri MD; Cagil, Nurullah MD

doi: 10.1097/ICO.0000000000001051
Clinical Science

Purpose: To assess the preoperative patient characteristics that may predict outcomes of keratoconus 2 years after corneal collagen cross-linking (CXL) in pediatric patients with keratoconus.

Methods: This retrospective study included 72 eyes of 52 consecutive patients with keratoconus under the age of 18 with 2-year follow-up after CXL. Subgroup analysis and cutoff values were determined as per age (<14 and ≥14 years), sex, baseline uncorrected and corrected distance visual acuities (UCVA, CDVA; <0.8 and ≥0.8 logMAR), topographic cone location (central and paracentral), maximum keratometry (K-max, <54 and ≥54 diopters), and corneal thickness at the thinnest point (thCT) (<450 and ≥450 μm) to evaluate the associations between preoperative patient characteristics and outcomes of CXL treatment in terms of K-max. Postoperative progression in K-max was defined as steepening of 1.0 diopter or more.

Results: Average age of patients was 14.8 ± 2.2 (9–17) years. After 2 years, the mean UCVA significantly improved and the mean thCT significantly decreased in all patients (P = 0.023, P < 0.001, respectively). The K-max in patients with paracentral cones and/or with thCT less than 450 μm were more likely to progress (cone location: P = 0.023, odds ratio = 3.21, 95% confidence interval, 1.17–8.72; thCT: P = 0.008, odds ratio = 4.54, 95% confidence interval, 1.46–14.14). Age, sex, baseline UCVA, CDVA, and K-max did not present any significant effect on progression of CXL after treatment (P > 0.05 for all variables).

Conclusions: In pediatric patients with keratoconus, cone location and the baseline thinnest corneal thickness seem to affect the success rate of CXL treatment after 2-year follow-up.

*Department of Ophthalmology, Ankara Ataturk Training and Research Hospital, Ankara, Turkey;

Department of Ophthalmology, Hacettepe University, Ankara, Turkey; and

Department of Ophthalmology, Ankara Ataturk Training and Research Hospital, Yildirim Beyazit University, Ankara, Turkey.

Reprints: Ozge Sarac, MD, Department of Ophthalmology, Ankara Ataturk Training and Research Hospital, Bilkent, Ankara, Turkey 06810 (e-mail:

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

Received May 21, 2016

Received in revised form August 28, 2016

Accepted August 30, 2016

Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.