Evaluation of 2 Riboflavin Dosing Regimens for Corneal CXL in Eyes With Progressive Keratoconus or Ectasia

Sunday, April 27, 2014: 3:41 PM
Room 151B (Boston Convention and Exhibition Center)
Adebukola O. Adebayo, MD, Price Vision Group, Indianapolis, IN, USA
Marianne O. Price, PhD, Cornea Research Foundation of America, Indianapolis, Indiana, USA
Francis W. Price Jr, MD, Price Vision Group, Indianapolis, Indiana, USA

Narrative Responses:

Purpose
This study compared safety and efficacy of two riboflavin-dosing intervals (2 vs. 5 minutes) during collagen cross-linking for treatment of progressive keratoconus or post-refractive ectasia to address concerns about whether more frequent application of a viscous riboflavin-dextran solution may impede UV-light penetration.

Methods
This prospective, randomized study enrolled subjects over 9 years old with progressive keratoconus or documented ectasia after refractive surgery. After epithelial removal, riboflavin 0.1% ophthalmic solution was applied topically every 2 minutes for 30 minutes, with penetration confirmed at a slit lamp. Then the eye was irradiated with a 365-nm 3-mW/cm2 UV light for 30 minutes.   The first treated eye per subject was randomized to riboflavin instillation at 2- or 5-minute intervals during UV-irradiation. Vision, keratometry and adverse events were assessed at baseline, 1 day, 1 week, 3 and 6 months after treatment.

Results
Two hundred patients were enrolled (149 keratoconus and 51 ectasia); 105 were randomized to the 2-minute and 95 to the 5-minute riboflavin application interval. At baseline, the median Kmax by tomography was 58D and median best corrected visual acuity (BCVA) was 20/40. From baseline to 6-months postop, the median improvement in Kmax was 0.1D in the 2-min group and 0.05D in the 5-min group, P=0.24, and median change in BCVA was 0 lines in the 2-min group and 1 line improvement in the 5-min group, P=0.096. Crosslinking appeared to stabilize corneas without progression and no corneas required retreatment or transplant.

Conclusion
The riboflavin application interval (2 vs. 5 minutes) during the 30-minute UV-irradiation did not significantly affect the efficacy or safety of the corneal crosslinking treatment for keratoconus or corneal ectasia.