title: Transient corneal thinning in eyes undergoing corneal cross-linking.
abstract: OBJECTIVE
  To report the corneal thinning during and after corneal cross-linking (CXL).
  
  
  METHODS
  Prospective, nonrandomized, single-center observational study.
  
  
  METHODS
  Thirty patients (30 eyes; 9 female, 21 male; age, 38 ± 12 years) were consecutively scheduled for CXL between January 23 and July 6, 2009. Twenty-four eyes had progressive keratoconus, 2 had pellucid marginal degeneration, 3 eyes had progressive keratectasia after a LASIK operation, and 1 eye had pseudophakic bullous keratopathy. Riboflavin-ultraviolet A (UVA)-induced CXL included the instillation of 0.1% riboflavin drops for 30 minutes followed by riboflavin instillation combined with UVA irradiation for another 30 minutes. Corneal thickness was measured preoperatively, during CXL, and after 1 and 6 months using an ultrasound pachymeter. Changes in the endothelial cell count, corneal steepness, refraction, and visual performance are also given.
  
  
  RESULTS
  On average, the corneas thinned 87 ± 40 μm (range, 37-206 μm; 19% ± 7%) during a 60-minute CXL treatment. In 1 patient, the cornea did not swell, even with hypotonic solution such that CXL would be safe. After 1 month, the corneal thickness was lower than the preoperative thickness, but after 6 months, the corneas had regained their original thicknesses. The endothelial cell count and corneal steepness were unchanged after CXL. The UCVA (uncorrected visual acuity) and BSCVA (best spectacle-corrected visual acuity) were improved 6 months after CXL.
  
  
  CONCLUSIONS
  Corneal thickness decreases significantly during CXL, even to a level where the health of the endothelium and cornea is jeopardized. Visual performance is improved 6 months after CXL.
authors: Cornea Service, Helsinki University Eye Hospital, Finland. juha.holopainen@hus.fi
authors: Juha M
authors: JM
authors: Holopainen
authors: Kari
authors: K
authors: Krootila
mesh_terms: D000328:Adult; D001837:Body Weights and Measures; D002452:Cell Count; D003094:Collagen / Q000378:metabolism; D003315:Cornea / Q000000981:diagnostic imaging / Q000473:pathology*; D003316:Corneal Diseases / Q000209:etiology*; D003319:Corneal Stroma / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D004728:Endothelium, Corneal / Q000473:pathology; D005260:Female; D006801:Humans; D007431:Intraoperative Complications; D008297:Male; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011183:Postoperative Complications; D011446:Prospective Studies; D012256:Riboflavin / Q000627:therapeutic use*; D014463:Ultrasonography; D014466:Ultraviolet Rays; D014792:Visual Acuity / Q000502:physiology
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin