Corneal collagen cross-linking shows early positive effects

Beverly Hills, CA-Corneal collagen cross-linking with riboflavin (C3-R) appears effective for stabilizing keratometry in corneas that are demonstrating instability associated with a variety of pathologies, according to a study presented by Munish Sharma, MD, MBBS.

To be eligible for this intervention, eyes had to demonstrate an unstable cornea, defined as a change in average K value of >2 D in less than 6 months. Keratoconus was the most common underlying pathology, but the cohort also included eyes with early ectasia post-LASIK or that had progressive hyperopia after previous radial keratotomy (RK) or laser thermal keratoplasty (LTK). Eyes that received simultaneous C3-R therapy and placement of corneal implants (Intacs, Addition Technologies) were not included.

"Our results confirm the report of Wollensak and Seiler that C3-R therapy may be a useful technique for stopping progression of keratoconus, and show its benefit for inducing stabilization by strengthening cornea collagen cross-linking. The benefit may also extend to eyes with other causes of corneal instability," Dr. Sharma said. "However, further study is needed with controls and longer follow-up to evaluate the efficacy better over the long term."

The treatment protocol involved application of the photosensitizing riboflavin 0.1% drops followed by 30 minutes of irradiation with ultraviolet-A light (370 nm, 5.4 J/cm²) to the central 7 mm of the cornea.

"Overall our technique is similar to that described by Wollensak and Seiler in their original 2003 article reporting on this approach except that we do not abrade the cornea prior to application of the riboflavin solution," Dr. Boxer Wachler said. "Epithelial removal is not necessary to achieve the treatment effect, and it goes without saying that patients are much more comfortable after the procedure if the epithelium remains intact."

In the retrospective study, the treatment was also associated with slight improvements in both uncorrected visual acuity and best-corrected visual acuity. Endothelial cell counts and IOP were monitored and showed no adverse effects.