title: Corneal collagen cross-linking:  ectasia and beyond.
abstract: OBJECTIVE
  Corneal collagen cross-linking has recently emerged as a novel approach for management of ectasia. This article reviews the literature published in the past 3 years about the expanding spectrum of cross-linking as a therapeutic modality and its complications.
  
  
  RESULTS
  Recent studies have confirmed the beneficial effects of cross-linking in stabilization and to a lesser extent, regression of keratoconus and postrefractive surgery ectasia. Other applications include cross-linking as a combined procedure with intracorneal ring segments, and photorefractive keratectomy for ectasia, corneal edema, and infectious keratitis. Animal studies of chemical cross-linking of sclera as a potential treatment for progressive myopia have also been performed. Various modifications of the technique to increase the safety profile of cross-linking have been reported, including the use of hypoosmolar riboflavin, transepithelial cross-linking, customized epithelial debridement, and higher fluence shorter duration ultraviolet A light exposure. Reported complications include keratitis, corneal haze, endothelial cell loss and failure of treatment.
  
  
  CONCLUSIONS
  Cross-linking has been shown to be an effective modality for corneal ectasia, the regression being less in patients with postrefractive ectasia than keratoconus. In a few studies, it has been found to be effective in symptomatic improvement of bullous keratopathy, and infectious keratitis but further studies are required. Cross-linking with epithelial debridement is found to be most effective but various modifications are being investigated for an improved, and better safety outcome.
authors.affiliation: Wills Eye Hospital, Jefferson Medical College of Thomas Jefferson University, 840 Walnut St., Philadelphia, PA 19107, USA.
authors.forename: Kunal
authors.initials: K
authors.lastname: Suri
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Hammersmith
authors.forename: Parveen K
authors.initials: PK
authors.lastname: Nagra
mesh_terms: D000818:Animals; D003094:Collagen / Q000378:metabolism*; D003319:Corneal Stroma / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D004108:Dilatation, Pathologic / Q000188:drug therapy / Q000209:etiology / Q000601:surgery; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D012256:Riboflavin / Q000627:therapeutic use; D014466:Ultraviolet Rays
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin