Transepithelial Accelerated Corneal Collagen Cross-Linking: Two-Year Results

PURPOSE: To report 2-year outcomes of trans-epithelial accelerated corneal collagen crosslinking (TE-ACXL) procedure in the treatment of progressive keratoconus patients. PATIENTS AND METHODS: Twenty-four eyes from 24 patients who underwent TE-ACXL (6mW/cm(2) for 15 minutes) were included in this retrospective interventional study. Best-corrected visual acuity (BCVA), keratometry values, thinnest corneal thickness (PachyMin) and topometric indexes were analysed preoperatively and at 6-month, 12-month, 18-month and 24-month postoperative. Progression was assessed by increase ≥1.00D in maximum keratometry (Kmax); increase ≥1.00D in corneal astigmatism; decrease ≥2% in PachyMin; increase ≥0.42 in D-index. RESULTS: There were no complications during or after TE-ACXL. No significant differences (Δ) were observed between baseline and 12-month or 24-month postoperative: ∆BCVA (−0.08 ± 0.25, p=0.190; −0.04 ± 0.17, p=0.588), ∆Kmax (−0.08 ± 1.32, p=0.792; −1.04 ± 1.89, p=0.135), ∆Astigmatism (−0.15 ± 0.89, p=0.485; −0.24 ± 1.38, p=0.609), ∆PachyMin (−0.56 ± 15.70, p=0.882; 0.56 ± 18.74, p=0.931), ∆Index Surface Variation (∆ISV) (−2.11 ± 10.27, p=0.395; −4.67 ± 17.32, p=0.442), ∆Index Vertical Asymmetry (∆IVA) (−0.05 ± 0.17, p=0.208; −0.08 ± 0.26, p=0.397), ∆Index Height Decentration (∆IHD) (0.00 ± 0.02, p=0.368; −0.01 ± 0.04, p=0.484), ∆KI (0.00 ± 0.05, p=0.851; 0.01 ± 0.06, p=0.877) and ∆D-index (0.15 ± 1.14, p=0.572; 0.06 ± 1.36, p=0.892). Eleven to 33% of patients had disease progression at 24-month postoperative according to the parameters used to determine progression. CONCLUSION: Although some patients maintain disease progression, TE-ACXL seems to be a safe and effective treatment for keratoconus over the 2-year follow-up period. Studies with longer follow-up periods and larger patient cohorts are recommended.