Corneal Ectasia

Cross-linking of collagen means the ability of collagen fibrils to form strong chemical bonds with adjacent fibrils (Ashwin and MaDonnell, 2010). In the cornea, collagen cross-linking occurs naturally with aging due to an oxidative deamination reaction which occurs within the end chains of the collagen fibrils and this natural cross-linkage of collagen explains why corneal ectasia often progresses most rapidly in adolescence or early adulthood but tends to be stable in patients after middle-age (Ashwin and MaDonnell, 2010). Human studies of UV-induced corneal cross-linking began in 2003 in Dresden, and early results were promising. The initial study involved patients with rapidly progressing keratoconus and all of them stopped progressing after treatment. Additionally, 70% of patients had flattening of their steep anterior corneal curvatures (decrease in average and maximum …show more content…
By absorbing UVA, the Riboflavin also prevents injury to deep ocular structures, including the endothelium, lens and retina (Wollensak et al., 2003a).
Indications:
The primary purpose of crosslinking is to stop the progression of ectasia. Likewise, the best candidate for this therapy is an individual with a progressive ectatic disease of the cornea. The most common indication is stage I and II keratoconus with evidence of progression like change in refraction (including astigmatism), uncorrected visual acuity, best corrected visual acuity, and corneal shape (topography and tomography). Other diseases that can be candidates include Pellucid Marginal Degeneration, Terrien Marginal Degeneration, post-refractive surgery (such as LASIK or Radial Keratotomy) ectasia and corneal melting conditions (Hayes et al.,