Optimizing Corneal Cross-Linking in the Treatment of Keratoconus: A Comparison of Outcomes After Standard- and High-Intensity Protocols

Purpose:To evaluate and compare the safety and efficacy of accelerated (AXL) and standard corneal cross-linking (CXL) protocols in patients with progressive keratoconus.Methods:Progressive keratoconus patients (14-40 years) received either standard-intensity CXL or high-intensity CXL (AXL). Corneas were exposed to ultraviolet-A 365 nm light for 30 minutes at an irradiance of 3.0 mW/cm(2) in the standard CXL group and to ultraviolet-A 365 nm light for 10 minutes at 9.0 mW/cm(2) in the AXL group. Changes in uncorrected visual acuity, best spectacle-corrected visual acuity, refractive astigmatism, K-max, and K-mean were used to determine treatment efficacy. Safety was determined by the incidence of adverse events and occurrence of loss of 2 or more lines of best spectacle-corrected visual acuity. Outcomes for CXL versus AXL were compared to determine differences in safety and efficacy between treatment groups.Results:Thirty-six eyes of 34 patients (mean age, 27.9 7.6 years) underwent AXL; 66 eyes of 53 patients (mean age, 30.0 +/- 8.0 years) underwent standard-intensity CXL. There was no significant difference in any outcome measures between the groups. For AXL, there seemed to be more corneal flattening, with a statistically significant reduction in K-mean at 6 and 12 months postoperatively, when compared preoperatively (P < 0.01). There were no adverse events or complications in any patients.Conclusions:There was more corneal flattening in AXL patients 6 to 12 months postoperatively, suggesting that AXL may be a promising alternative to CXL in stabilizing corneal ectasia.