Corneal crosslinking without epithelial removal

Abstract

Purpose: To evaluate the effect of riboflavin-ultraviolet (UV)-A corneal crosslinking (CXL) without epithelial removal on ectatic corneal disease.

Setting: Woolfson Eye Institute, Atlanta, Georgia, USA.

Design: Prospective observational study.

Methods: Patients were treated with a new riboflavin formulation without epithelial removal, then exposed to UV light (365 nm) at 4 mW/cm² with on-off cycling for 30 minutes. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, maximum corneal curvature (maximum keratometry [Kmax]), total higher-order aberrations (HOAs), and coma were measured at 3, 6, 12, and 24 months postoperatively. Progression was defined as an increase of more than 1 diopter (D) in Kmax and loss of more than 1 line of CDVA.

Results: Five hundred twelve eyes of 308 patients with keratoconus or forme fruste keratoconus and 80 eyes of 55 patients with ectasia after laser in situ keratomileusis (LASIK) were treated with the new riboflavin formulation without epithelial removal; 229 patients received bilateral treatments, 95 of which were simultaneous. The mean UDVA and CDVA improved by 1 to 1.5 Snellen lines at 1 and 2 years postoperatively (P < .0001). Mean Kmax decreased by 0.48 D at 2 years postoperatively (P = .0002). Mean total HOAs and coma decreased by 36% (P < .0001) and 37% (P = .0002), respectively, at 2 years postoperatively. Kmax decreased more than 1 D in three times as many eyes as it increased more than 1 D (P < .0001). No eyes progressed, and there was no loss of effect between 1 and 2 years postoperatively. No vision-threatening events were observed. Pain typically resolved within 24 hours, and visual acuity returned to preoperative levels in 1 to 2 days.

Conclusion: Epithelium-on CXL using this new protocol halted the progression of keratoconus and ectasia after LASIK. It was safer and provided more rapid visual recovery than CXL with epithelial removal, allowing routine bilateral, simultaneous treatment.