Three-year follow-up of accelerated versus standard corneal cross-linking in paediatric Keratoconus

Purpose Standard corneal collagen cross-linking (S-CXL) is an effective treatment to arrest Keratoconus (KC) progression in children. Less is known on the long-term efficacy of accelerated CXL (A-CXL) in paediatric populations. Methods A historical cohort analysis of paediatric patients (<= 18 years) with KC who underwent S-CXL and A-CXL at two tertiary referral centres in Israel between 2010-2017. Preoperative and 3-year postoperative evaluation included changes in visual acuity (best spectacle corrected [BSCVA]) and uncorrected [UCVA]), refractive errors, and keratometric data. Results Ninety-three eyes of 93 patients were analysed (A-CXL: n = 39; S-CXL: n = 54). Baseline characteristics were similar between groups. Both groups showed a significant improvement in visual acuity compared to baseline (S-CXL: 0.810-0.602 LogMAR UCVA; A-CXL: 0.890-0.306 LogMAR UCVA, p < 0.05 for both). Improvement in BSCVA and UCVA following A-CXL was non-inferior to S-CXL (< +/- 0.2 LogMAR). Kmax decreased by a mean of 0.98 +/- 5.56 dioptres following S-CXL (p = 0.02) and by 1.48 +/- 8.4 dioptres following A-CXL (p = 0.015). Thinnest pachymetry decreased following both treatments (S-CXL: by 26.8 +/- 40.7 mu m, p = 0.001, A-CXL: by 10.2 +/- 13.4 mu m, p = 0.028), the difference between groups was within the non-inferiority margin (< +/- 10 mu m). Conclusions Paediatric patients followed for three years after A-CXL showed improved visual function, reduced corneal astigmatism and Kmax, and decreased thinnest corneal thickness. A-CXL was non-inferior to S-CXL at three years in terms of best-corrected and uncorrected visual acuity, thinnest pachymetry, and astigmatism. For Kmax, non-inferiority could not be concluded.