Safety and efficacy of contact lens-assisted accelerated corneal cross-linking using Nelfilcon A in thin corneas

To evaluate the efficacy and safety of contact lens-assisted accelerated corneal cross-linking (A-CACXL) using a UV-filter-free nelfilcon A daily hydrogel lens in thin corneas (≤ 400 µm).

Retrospective single-center series of 28 eyes (23 patients) with progressive keratoconus and post-debridement pachymetry ≤ 400 µm; minimum follow-up 6 months. A-CACXL employed a 100-µm nelfilcon A lens. Outcomes at Baseline, Month 1, Month 3, and Month 6 included UCVA/BCVA (logMAR), refraction, K1, K2, Kmean, Kmax (D), minimum corneal thickness (MCT, µm), and endothelial cell count (ECC, cells/mm²). Longitudinal changes were analyzed with repeated-measures ANOVA (Greenhouse-Geisser when required) or Friedman, with Bonferroni-adjusted pairwise tests only if the omnibus test was significant; correlations were pre-specified for ΔBCVA vs ΔK (Δ = month 6-Baseline).

BCVA improved significantly (p = 0.005), whereas UCVA showed a non-significant favorable trend (p = 0.246). K2 and Kmean decreased over time (p < 0.001 and p < 0.001), and Kmax decreased with Greenhouse-Geisser correction (p = 0.033); K1 remained stable (p = 0.233). MCT demonstrated an early thinning at Month 1 and Month 3 with partial rebound by Month 6 (omnibus p < 0.001; Bonferroni-significant vs Baseline). Manifest cylinder decreased modestly (p = 0.048), whereas manifest sphere was unchanged (p = 0.495). ECC remained stable across visits (p = 0.124). Adverse events were limited to transient, clinically insignificant haze in 2/28 eyes (7.1%), resolving by Month 3. All eyes satisfied the intraoperative functional thickness ≥ 400 µm threshold.

A-CACXL with a nelfilcon A lens appears to be a pragmatic, safe, and effective option for thin corneas, yielding early BCVA improvement, modest anterior flattening, and preserved endothelium through six months.