Six-Month Outcomes of Accelerated Corneal Cross-Linking with a Total Dose of 7.2 J/cm2 Using Dextran-Free Riboflavin

To evaluate the 6-month clinical outcomes of accelerated corneal cross-linking (A-CXL) using a total energy dose of 7.2 J/cm2 with a 0.1% dextran-free riboflavin solution containing hydroxypropyl-methylcellulose (HPMC) in patients with progressive keratoconus.

A total of 42 eyes from 35 patients with progressive keratoconus underwent epithelial removal, followed by the application of 0.1% dextran-free riboflavin solution with HPMC every 30 seconds for 10 minutes. A-CXL was performed using ultraviolet A irradiation at 12 mW/cm2 for 10 minutes, delivering a total energy dose of 7.2 J/cm2. Evaluations included uncorrected distance visual acuity, corrected distance visual acuity, keratometric indices (flat, steep, and maximum keratometry), central corneal thickness, endothelial cell density, corneal astigmatism, and demarcation line depth using anterior-segment optical coherence tomography. Each keratometric index was measured three times, and mean values were recorded.

Corrected distance visual acuity improved significantly from 0.55 ± 0.29 to 0.36 ± 0.23 logarithm of the minimum angle of resolution (p < 0.001). Keratometric indices showed significant reductions, with the mean maximum keratometry decreasing from 57.06 ± 5.7 to 55.4 ± 5.5 diopters (D; p < 0.001). Astigmatism, as represented by cylindrical power, decreased slightly from -3.98 ± 1.98 D preoperatively to -3.75 ± 1.94 D postoperatively; however, this change was not statistically significant (p = 0.122). Central corneal thickness was significantly reduced from 471.6 ± 32.4 to 461.4 ± 31.7 µm (p < 0.001), while uncorrected distance visual acuity remained unchanged (p = 0.070). The mean demarcation line depth was 287.82 ± 39.77 µm. No significant change was observed in endothelial cell density (p = 0.090), and no minor postoperative complications were encountered.

A-CXL using a total energy dose of 7.2 J/cm2 with 0.1% dextran-free riboflavin effectively stabilizes keratoconus progression, significantly improves visual acuity and corneal astigmatism, and preserves endothelial integrity over a 6-month follow-up. Further long-term studies are required to validate these findings.