Standard corneal collagen crosslinking versus transepithelial iontophoresis‐assisted corneal crosslinking, 24 months follow‐up: randomized control trial

Abstract

Purpose

To compare the results of standard corneal crosslinking ( CXL) and transepithelial iontophoresis‐assisted CXL after 24 months follow‐up.

Material and methods

Corneal crosslinking (CXL) was performed in a series of 149 eyes of 119 patients with keratoconus I–II of Amsler classification. Depending on the CXL method, patients were divided into two groups: (1) 73 eyes with standard CXL and (2) 76 eyes with transepithelial iontophoresis‐assisted CXL. Depending on the group, epithelium removal or administration of riboflavin solution by iontophoresis for 10 min was performed, after which standard surface UVA irradiation (370 nm, 3 mW/cm ²) was performed at a 5‐cm distance for 30 min.

Results

A statistically significant difference in corrected distance visual acuity ( CDVA) was observed between the two groups, with a better outcome in the second group after 6 months (p = 0.037); however, no significant difference was found 24 months after treatment (p = 0.829). Stabilization and regression of keratometry values were achieved in both groups, but standard CXL was more effective. The average demarcation line depth in the standard CXL group was 292 ± 14  μm after 14 days and 172 ± 16  μm in the transepithelial iontophoresis‐assisted CXL group. No demarcation line was detected after 1 month and 3 months in 45% and 100% of the eyes in the second group respectively.

Conclusion

Transepithelial iontophoresis‐assisted collagen crosslinking showed to be less effective than standard CXL after 24 months of follow‐up, possibly due to a more superficial formation of corneal collagen crosslinks, however the stopping of disease progression was achieved 24 months after procedure.