title: Results of confocal microscopy examinations after collagen cross-linking with riboflavin and UVA light in patients with progressive keratoconus.
abstract: OBJECTIVE
  Keratoconus is a predominantly bilateral form of corneal degeneration that is associated with central thinning and cone-shaped bulging of the cornea usually accompanied by a progressive reduction in visual acuity. A recent therapeutic option is cross-linking, a procedure designed to prevent the progression of keratoconus by the photochemical cross-linkage of collagen fibers.
  
  
  METHODS
  Eight eyes in 8 patients with progressive keratoconus were treated by the photochemical cross-linking method using riboflavin and UVA light. In addition to the usual ophthalmological examinations, patients were examined pre- and postoperatively by confocal in vivo laser scanning microscopy. Follow-up examinations were performed at 2 weeks and at 2, 4, 6 and 12 months postoperatively.
  
  
  RESULTS
  Complete regeneration of corneal epithelium was detected by 2 weeks after therapy at the latest. The sub-basal nerve plexus could not be visualized by confocal microscopy after treatment. Immediately after treatment, the anterior corneal stroma had a honeycombed appearance but without the typical hyperreflective keratocyte nuclei. At about 6 months postoperatively, the corneal stroma had virtually regained its normal configuration. After therapy, confocal microscopy revealed that corneal endothelium was normal in terms of cell density and morphology at every time point.
  
  
  CONCLUSIONS
  Confocal in vivo laser scanning microscopy is an investigative technique that permits reproducible visualization of structural changes in the cornea (epithelium, stroma and endothelium) following collagen cross-linking with riboflavin and UVA light. Once epithelial healing is complete, the epithelium and endothelium appear to be unaffected by the treatment. The most noteworthy structural changes, which are detected on confocal microscopy shortly after treatment, involve the anterior and middle corneal stroma. Over the course of time, up to 12 months postoperatively, these changes show a definite tendency to regress.
authors.affiliation: Department of Ophthalmology, University of Rostock, Doberaner Strasse 140, Rostock, Germany. SteffiKN74@gmx.de
authors.forename: Steffi
authors.initials: S
authors.lastname: Knappe
authors.forename: Oliver
authors.initials: O
authors.lastname: Stachs
authors.forename: Andrey
authors.initials: A
authors.lastname: Zhivov
authors.forename: Marina
authors.initials: M
authors.lastname: Hovakimyan
authors.forename: Rudolf
authors.initials: R
authors.lastname: Guthoff
mesh_terms: D000328:Adult; D002452:Cell Count; D003094:Collagen / Q000378:metabolism*; D003319:Corneal Stroma / Q000378:metabolism / Q000473:pathology*; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D018450:Disease Progression; D004728:Endothelium, Corneal / Q000473:pathology; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D008297:Male; D018613:Microscopy, Confocal; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use; D012256:Riboflavin / Q000627:therapeutic use*; D016896:Treatment Outcome; D014466:Ultraviolet Rays
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin