Corneal topography and aberrometry changes one-year after transepithelial corneal cross-linking using iontophoresis versus standard corneal cross-linking

Abstract

Purpose : To assess the 1-year corneal topography and aberrometry changes after transepithelial corneal crosslinking using iontophoresis (T-ionto CL) versus standard crosslinking (standard CL) for the treatment of progressive keratoconus.

Methods : Thirty-four eyes of 25 participants were randomized into T-ionto CL (22 eyes) or standard CL (12 eyes) treatment. T-ionto CL was performed by using an iontophoresis device with dextran-free 0.1% riboflavin solution and by irradiating the cornea with 10 mW/cm² UV-A device for 9 minutes. Standard CL was performed according to the Dresden protocol. Participants underwent ophthalmic examinations preoperatively and 3-days, 1-week, 1-, 3-, 6- and 12-months after treatment. Changes of corneal shape and optical performance were assessed by analysis of the maximum simulated keratometry (K_max), central corneal thickness (CCT) and corneal high-order wavefront aberration (from 3^rd to 7^th orders). Other outcome measures included corrected distance visual acuity (CDVA) and manifest refraction.

Results : Twelve months after T-ionto CL and standard CL, K_max averagely flattened by 0.52±1.30 D (P=0.06) and 0.82±1.20 D (P=0.04) respectively. No significant average changes were found in corneal high-order wavefront aberration after T-ionto (from 1.94±0.91 µm to 2.00±0.79 µm; P=0.56) and Standard CL (from 2.24±0.77 µm to 2.12±0.85 µm; P=0.16) groups respectively. The average CCT did not significantly change at 12 months from preoperatively in either group (T-ionto CL: +9 µm; P=0.07; Standard CL: -1 µm; P=0.80). The mean change in CDVA was -0.10±0.12 logMAR (P=0.003) and -0.03±0.06 logMAR (P=0.10) after T-ionto CL and standard CL respectively. The manifest spherical equivalent refraction changed averagely by +0.71±1.44 D (P=0.03) and +0.21±0.76 D (P=0.38) respectively. No statistically significant differences were found in the outcome measures between treatments.

Conclusions : At 1 year, there was an average improvement in corneal shape, visual and refractive outcomes after T-ionto CL, though average K_max flattening was lower than standard CL. No changes were found in the optical performance of the cornea after the operation.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.