Comparative Results Between "Epi-Off" Conventional and Accelerated Corneal Collagen Crosslinking for Progressive Keratoconus in Pediatric Patients

Purpose: The aim of our study was to evaluate the efficacy and safety of epi-off conventional and accelerated corneal collagen cross-linking in the treatment of progressive keratoconus in pediatric patients up to 4 years after treatment. Patients and methods: Conventional (standard) CXL epi-off technique was performed in 37 eyes (S-CXL group) and accelerated CXL in 27 eyes (A-CXL group). Refraction, keratometry, cylindrical equivalent, spherical equivalent, slit lamp examination, pachymetry, corneal tomography, anterior segment ocular coherence tomography and visual acuity were performed up to 4 years. Results: In the S-CXL group: the flat K values decreased from 47.41 +/- 3.39 D to 45.36 +/- 3.62 D at 4 years (p=0.004); steep K decreased from 51.98 +/- 4.11 to 50.21 +/- 4.81 D at 4 years (p=0.0078); mean K decreased with 1.99 D at 4 years (p=0.009). In the A-CXL group: the flat K values decreased from 46.97 +/- 4.17 D to 44.97 +/- 4.24 D at 4 years (p=0.048); steep K decreased from 50.55 +/- 4.10 D to 48.75 +/- 4.17 D at 4 years (p=0.0287); mean K decreased from 48.79 +/- 3.86 D to 46.86 +/- 4.11 D at 4 years (p=0.0356). The preoperative mean UCVA in the S-CXL group was 0.8 +/- 0.23 logMar and improved during the follow-up reaching 0.65 +/- 0.24 logMar at 4 years (p=0.072). The baseline mean UCVA in A-CXL group was 0.77 +/- 0.25 logMar and increased during the follow-up to 0.63 +/- 0.25 logMar at 4 years (p=0.0039). A similar improvement of BCVA was observed during the follow-up. Conclusion: Epi-off conventional and accelerated CXL are efficient procedures for progressive keratoconus in pediatric patients. Accelerated and conventional CXL were comparable at all time points and both represent viable options for the therapy of KC in these patients.