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

Objective: 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.