Because of increasing numbers of cases with corneal and limbal thinning, ways to stop or reverse the degenerative changes induced by corneal surgery (radial incisions, laser-assisted in situ keratomileusis (LASIK), lamellar keratoplasty) and degenerative diseases such as keratoconus have become imperative. These include several surgical and non-surgical modalities (vitamin therapy, ultraviolet (UV) light therapy and cross-linking).
Originally developed as a new method to strengthen the weakened corneas of keratoconus, riboflavin CXL has been shown to strengthen the corneas in post-LASIK ectasias and in marginal corneal dystrophies.1,2 Progressive irregular thinning (ectasia) is problematic and possible with any LASIK procedure.
Cross-linking of collagen refers to the ability of collagen fibrils to form strong chemical bonds with adjacent fibrils. Some naturally occurs in the cornea with aging (as in other parts of the body), but for immediate therapeutic effect, chemical agents (UV-activated riboflavin) are used. In a number of studies, CXL has been shown to effectively stop the advancement of ectasia in eyes following excimer laser ablation. In an early German study with corneal cross-linking, the biomechanical status of the cornea was stabilized with a halting of the refractive and topographic progression of ectasia.1
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