title: Does Corneal Collagen Cross-linking Reduce the Need for Keratoplasties in Patients With Keratoconus?
abstract: OBJECTIVE
  To investigate whether the introduction of corneal collagen cross-linking (CXL) influences the frequency of keratoplasties in patients with keratoconus.
  
  
  METHODS
  Data were obtained from a cohort of patients from our corneal transplant registry. Two different periods were compared, 2005 to 2006 (period 1) and 2013 to 2014 (period 2). Patients during period 1 had surgery before the introduction of CXL treatment, and patients in period 2 had surgery after this treatment was well established in our department. Age and gender were registered, and the Amsler-Krumeich classification system was applied to grade the degree of keratoconus.
  
  
  RESULTS
  The total number of keratoplasties performed during period 1 was 137, and keratoconus was the cause of surgery in 55 eyes (55 patients). The corresponding numbers in period 2 were 231 and 26 eyes (26 patients), respectively. The difference in the number of keratoplasties for keratoconus in both periods was statistically significant (P = 0.003). There were no significant differences in the distributions of age and gender between both periods. In period 1, 63.6% of the eyes were graded as stage 4 in the Amsler-Krumeich classification, compared with 96.2% in period 2 (P = 0.001).
  
  
  CONCLUSIONS
  The frequency of keratoplasty for keratoconus has been more than halved in our department over the last decade. There is reason to believe that this reduction is for a great part caused by the introduction of CXL treatment.
authors.affiliation: *Department of Ophthalmology, Oslo University Hospital, Ullevaal, Oslo, Norway; and †Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Gunhild Falleth
authors.initials: GF
authors.lastname: Sandvik
authors.forename: Andreas
authors.initials: A
authors.lastname: Thorsrud
authors.forename: Marianne
authors.initials: M
authors.lastname: Råen
authors.forename: Atle E
authors.initials: AE
authors.lastname: Østern
authors.forename: Marit
authors.initials: M
authors.lastname: Sæthre
authors.forename: Liv
authors.initials: L
authors.lastname: Drolsum
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003094:Collagen / Q000378:metabolism*; D003319:Corneal Stroma / Q000378:metabolism*; D019781:Corneal Topography; D003432:Cross-Linking Reagents; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy / Q000378:metabolism / Q000601:surgery / Q000628:therapy*; D015948:Keratoplasty, Penetrating / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D012256:Riboflavin / Q000627:therapeutic use; D014466:Ultraviolet Rays; D014792:Visual Acuity; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin