APR 16, 2013
This prospective study found that riboflavin/ultraviolet A corneal cross-linking (CXL) appears effective and safe for halting the progression of keratoconus for at least four to six years. I hope the FDA will approve this soon as it seems like a wonderful treatment based on the literature I've read.
The authors examined 30 patients (30 eyes) who had undergone CXL following epithelial removal four to six years earlier. Improvements in topographic and wave-front parameters evident at one year continued to improve at four to six years. There were no long-term adverse events, and no eye lost more than one line of BSCVA.
They write that a very interesting finding was the continuation of improvement of visual and topographic parameters with time. Keratoconic corneas have shown increased proteinase enzyme activity and reduced proteinase inhibitor activity. It's possible that CXL reduces the efficacy of these enzymes, reducing stromal protein digestion, while laying down new collagen and extracellular matrix continues as part of normal physiological processes, resulting in improvement in corneal biomechanics and shape and an increase in corneal thickness.
The authors note that only eyes with grade I to II keratoconus, according to Amsler-Krumeich's classification, were included, and no eyes had mean simulated keratometry values greater than 54D. Therefore, this study cannot elucidate the long-term stability of CXL in advanced keratoconus, for which CXL might not be so promising.