Outcomes Of High-Fluence (7.2 J/Cm²) Accelerated Collagen Cross-Linking In Advanced Keratoconus

To evaluate the effectiveness and safety of a high-fluence accelerated epithelium-off corneal collagen cross-linking (CXL) protocol (12 mW/cm² for 10 minutes; total fluence 7.2 J/cm²) in eyes with advanced keratoconus (preoperative Kmax ≥58 D) over 12 months, and to describe keratometric, tomographic, visual, refractive, and endothelial outcomes, including rates of stabilization and progression.

Tertiary referral university eye clinic.

This retrospective cohort study included 109 eyes of 96 patients with advanced keratoconus, defined as a preoperative maximum keratometry (Kmax) value ≥58 diopters. All eyes underwent an epithelium-off accelerated CXL protocol using an irradiance of 12 mW/cm² for 10 minutes (total fluence: 7.2 J/cm²) and completed a minimum follow-up of 12 months. Corneal topography, manifest refraction, visual acuity, and endothelial cell density were evaluated preoperatively and at 1, 6, and 12 months postoperatively.

The study included 109 eyes from 96 patients (mean age 25.6 ± 4.4 years). Mean Kmax decreased from 63.56 ± 4.97 D preoperatively to 60.31 ± 4.20 D at 12 months (p = 0.001). Central and thinnest corneal thickness showed significant postoperative reductions (both p = 0.001). Kmax progression occurred in 12 eyes (11%), while 82 eyes (75.2%) demonstrated ≥1 D flattening. BCVA improved significantly (0.60 ± 0.28 to 0.52 ± 0.26 logMAR; p = 0.047), whereas UCVA did not change significantly (p = 0.200). No significant endothelial cell loss was observed (p = 0.058). Two cases of transient corneal edema resolved within 3 months, and one eye required keratoplasty.

High-fluence accelerated corneal collagen cross-linking using 12 mW/cm² for 10 minutes (total fluence 7.2 J/cm²) was effective in stabilising corneal ectasia in eyes with advanced keratoconus over 12 months. Significant reductions in Kmax and improvements in best-corrected visual acuity were achieved, with most eyes demonstrating topographic stabilisation or flattening. The procedure showed an acceptable safety profile, with no statistically significant endothelial cell loss and a low incidence of clinically relevant complications. These findings suggest that high-fluence accelerated CXL may represent a practical treatment option for selected patients with advanced keratoconus.