Biomechanical and Tomographic Outcomes in Pediatric Keratoconus Treated with Conventional Epithelium-Off Corneal Collagen Cross-Linking

Background and Objectives: Pediatric keratoconus often progresses rapidly and may require early intervention. This study evaluated 24-month visual, tomographic, pachymetric, and biomechanical outcomes after conventional epithelium-off (Dresden protocol) corneal collagen cross-linking (CXL) in pediatric keratoconus using Pentacam tomography and Corvis ST dynamic Scheimpflug analysis. Materials and Methods: This single-center longitudinal cohort included 28 eyes of 23 patients aged 13–18 years treated at the OCULENS Clinic, Cluj-Napoca, Romania, between 2019 and 2023. Baseline, 6-, 12-, and 24-month values were analyzed for UCVA, BCVA, Kmax, thinnest pachymetry, SP-A1, deformation amplitude (DA), first and second applanation times (A1T and A2T), highest concavity (HC) radius, and BAD-D. Repeated-measures ANOVA assessed longitudinal change, and Pearson correlation tested the association between Kmax and SP-A1. Results: UCVA improved from 0.53 ± 0.16 to 0.44 ± 0.16 logMAR and BCVA from 0.31 ± 0.11 to 0.25 ± 0.11 logMAR (both p < 0.001). Mean Kmax decreased from 54.36 ± 3.11 D to 53.41 ± 2.79 D, while SP-A1 increased from 84.69 ± 4.75 to 97.39 ± 5.11 (both p < 0.001). Thinnest pachymetry showed early postoperative thinning with partial recovery by 24 months. DA decreased, A1T increased, A2T decreased, HC radius increased, and BAD-D decreased significantly (all p < 0.001). Kmax and SP-A1 were strongly inversely correlated at all visits (r = -0.714 to -0.773; all p < 0.001). Outside the formal 24-month analytic window, later clinical follow-up identified three eyes that required retreatment at approximately 3 years and one patient who subsequently developed an indication for keratoplasty. Conclusion: Conventional epithelium-off CXL in pediatric keratoconus was associated with improved visual acuity, modest tomographic flattening, sustained biomechanical stiffening, and overall structural stabilization over 24 months; however, a small subset showed late progression, supporting the need for continued long-term surveillance. Keywords: pediatric keratoconus; corneal collagen cross-linking; Pentacam; Corvis ST; corneal tomography; corneal biomechanics; adolescents Abbreviations: BCVA, best-corrected visual acuity; CXL, corneal collagen cross-linking; KC, keratoconus; Kmax, maximum keratometry; logMAR, logarithm of the minimum angle of resolution; SP-A1, stiffness parameter at first applanation; UCVA, uncorrected visual acuity; UVA, ultraviolet A.