Related Experiment Video
Updated: Apr 5, 2026

Three Different Protocols of Corneal Collagen Crosslinking in Keratoconus: Conventional, Accelerated and Iontophoresis
Published on: November 12, 2015
Transepithelial Versus Epithelium-Off Corneal Collagen Cross-Linking for Progressive Keratoconus: A Prospective
Mashhoor F Al Fayez1, Salman Alfayez, Yasmin Alfayez
1*Department of Ophthalmology, King Abdul Aziz University Medical School; †The Eye and Laser Centre; and ‡The Eye Hospital, Jeddah, Saudi Arabia.
Purpose:
To compare the safety and efficacy of transepithelial with epithelium-off corneal cross-linking for progressive keratoconus.
Methods:
In a prospective clinical trial, 70 patients with progressive keratoconus were randomized to undergo corneal cross-linking with intact epithelium (n = 34) or after deepithelialization (n = 36). The main outcome measure was a change in the maximum K reading (K(max)).
Results:
With 3-year follow-up, K(max) decreased in the epithelium-off group with a mean of 2.4 D and no patient showed evidence of progression. In the transepithelial group, K(max) increased by a mean of 1.1 D, and 20 patients (55%) showed progression of keratoconus.
Conclusions:
In this study, epithelium-off was significantly more effective than transepithelial corneal cross-linking in halting the progression of keratoconus (P < 0.0001).

