title: One-year follow-up of corneal confocal microscopy after corneal cross-linking in patients with post laser in situ keratosmileusis ectasia and keratoconus.
abstract: OBJECTIVE
  To investigate corneal tissue alterations after corneal collagen cross-linking in patients with post laser in situ keratosmileusis (LASIK) keratectasia and keratoconus.
  
  
  METHODS
  Prospective comparative case series.
  
  
  METHODS
  Five patients (5 eyes) with iatrogenic keratectasia after LASIK and 5 patients (5 eyes) with progressive keratoconus were included. All eyes underwent corneal cross-linking and were assessed by corneal in vivo confocal microscopy. Three normal/healthy and 3 post-LASIK without ectasia corneas were also examined as controls.
  
  
  RESULTS
  All corneas revealed normal epithelial thickness before and after surgery. Images of both keratoconic and post-LASIK corneal ectasia eyes revealed similar morphologic alterations. The subepithelial nerve plexus was absent immediately after treatment; regeneration of nerves was evident after the third postoperative month. Keratocytes were absent from the anterior 300 mum of the stroma in the first 3 months while the posterior stromal density of keratocytes was increased. Corneal collagen fibers in the anterior stroma were distributed unevenly in a net-like formation. Full-thickness keratocyte repopulation in the anterior and mid-corneal stroma was detected 6 months after treatment. The corneal endothelium did not undergo any significant changes, since the cell density and hexagonality was not found altered during the follow-up period.
  
  
  CONCLUSIONS
  Keratocyte nuclei apoptosis in the anterior and intermediate corneal stroma along with collagen alterations were observed during the first 3 postcorneal cross-linking months. Gradual keratocyte repopulation was demonstrated over the following months. Corneal alterations after corneal cross-linking were similar in both keratoconic and post-LASIK corneal ectasia eyes.
authors.affiliation: Institute of Vision and Optics, University of Crete, Crete, Greece. kymionis@med.uoc.gr
authors.forename: George D
authors.initials: GD
authors.lastname: Kymionis
authors.forename: Vasilios F
authors.initials: VF
authors.lastname: Diakonis
authors.forename: Maria
authors.initials: M
authors.lastname: Kalyvianaki
authors.forename: Dimitra
authors.initials: D
authors.lastname: Portaliou
authors.forename: Charalampos
authors.initials: C
authors.lastname: Siganos
authors.forename: Vasilios P
authors.initials: VP
authors.lastname: Kozobolis
authors.forename: Aristophanis I
authors.initials: AI
authors.lastname: Pallikaris
mesh_terms: D003094:Collagen / Q000378:metabolism*; D003319:Corneal Stroma / Q000378:metabolism / Q000473:pathology*; D004108:Dilatation, Pathologic / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism; D005500:Follow-Up Studies; D006801:Humans; D007049:Iatrogenic Disease; D007640:Keratoconus / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D018613:Microscopy, Confocal; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011183:Postoperative Complications; D011446:Prospective Studies; D012256:Riboflavin / Q000627:therapeutic use; D014466:Ultraviolet Rays
chemical_list: D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin