Macular safety and outcomes of accelerated cross-linking with a 7.2 J/cm² energy dose in keratoconus: A prospective case series

Abstract: PURPOSE: The purpose of this study was to evaluate the macular safety and clinical outcomes of an accelerated Corneal collagen crosslinking (CXL) protocol using 12 mW/cm² ultraviolet-A (UV-A) irradiation for 10 min (total energy dose: 7.2 J/cm²) with dextran-free riboflavin, assessing its efficacy and posterior segment safety in patients with progressive keratoconus. METHODS: Seventeen eyes of 17 patients with progressive keratoconus underwent accelerated epithelium-off CXL using 12 mW/cm² UV-A irradiation for 10 min (total energy: 7.2 J/cm²). Dextran-free 0.1% riboflavin was instilled following epithelial debridement. Treatment proceeded only if corneal thickness was ≥400 μm. Pre- and 12-month postoperative assessments included best-corrected visual acuity (BCVA), corneal topography, endothelial cell count, multifocal electroretinography (mfERG), and enhanced depth imaging optical coherence tomography. Lens clarity was evaluated by slit-lamp biomicroscopy. The Wilcoxon signed–rank test was used for paired comparisons; P < 0.05 was considered statistically significant. RESULTS: Although the median BCVA improved from 0.46 to 0.38 logarithm of the minimum angle of resolution, this change was not statistically significant ( P = 0.15). mfERG analysis showed increased P1 wave amplitudes and decreased implicit times across most retinal rings; however, these changes were also not statistically significant. Choroidal vascular parameters remained stable without significant alterations. No adverse events or lenticular opacities were observed during the follow-up period. CONCLUSION: The accelerated continuous CXL protocol delivering a total energy dose of 7.2 J/cm² demonstrated macular safety over 12 months, with no significant impact on choroidal vascular structure or retinal function. These findings support the safety and potential efficacy of this protocol in stabilizing progressive keratoconus and highlight the need for further long-term, controlled studies to validate its outcomes.