title: [Treatment of keratoconus by collagen cross linking].
abstract: BACKGROUND
  We were able to show a significant increase in corneal stiffness of rabbit and porcine eyes after combined riboflavin/UVA-induced collagen cross-linking. In this study,we tried to treat keratoconus patients with this method to stop the progression of corneal ectasia.
  
  
  METHODS
  We treated 16 eyes of 15 patients with progressive keratoconus and mostly moderate keratectasia (48-56 dpt). After removal of the epithelium (7 mm X), riboflavin solution was applied on the cornea, which was irradiated with UVA (370 nm,3 mW/cm(2)) at a distance of 1 cm for 30 min.Post-operative follow-up controls were conducted every 3 months in the first year and then every 6 months, always including visual acuity testing, corneal topography and measurements of endothelial cell density. The follow-up time was between 1 and 3 years.
  
  
  RESULTS
  Progression of keratectasia was stopped in all patients. Best corrected visual acuity and the maximal keratometry values improved slightly in about 50% of the cases. In all patients corneal transparency, the degree of keratectasia registered by corneal topography and the density of endothelial cells remained unchanged within the follow-up time. No negative side-effects were observed.
  
  
  CONCLUSIONS
  Our results show that collagen cross linking might be a useful conservative treatment modality to stop the progression of keratoconus. By this means the need for keratoplasty might be significantly reduced. Given the simplicity of the technique and minimal costs of the treatment it might also be well suited for developing countries.Further studies are envisaged to exclude long-term side effects and to evaluate the long term durability of the mechanical stiffness effect.
authors.affiliation: Universitäts-Augenklinik Dresden. gwollens@hotmail.com
authors.forename: G
authors.initials: G
authors.lastname: Wollensak
authors.forename: E
authors.initials: E
authors.lastname: Spörl
authors.forename: T
authors.initials: T
authors.lastname: Seiler
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002452:Cell Count; D003094:Collagen / Q000187:drug effects*; D019781:Corneal Topography; D003432:Cross-Linking Reagents / Q000008:administration & dosage*; D004728:Endothelium, Corneal / Q000187:drug effects; D005260:Female; D005486:Flavin Mononucleotide / Q000008:administration & dosage*; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy; D013552:Swine; D014792:Visual Acuity / Q000187:drug effects
chemical_list: D003432:Cross-Linking Reagents; D005486:Flavin Mononucleotide; D003094:Collagen