title: Wound healing following intrastromal photorefractive keratectomy with the Nd:YLF picosecond laser in the cat.
abstract: BACKGROUND
  We studied the histopathology of the stromal wound healing response in the cat cornea following intrastromal photorefractive keratectomy (IPRK) with the Nd:YLF picosecond laser.
  
  
  METHODS
  Intrastromal PRK was performed in the anterior stroma of cat corneas with the Nd:YLF picosecond laser. The cats were sacrificed at predetermined intervals ranging from immediately to 6 months postoperatively. Effects of the laser treatment on the epithelium, Bowman's layer, stroma, and the endothelium were evaluated using light and scanning electron microscopy. No anti-inflammatory agents were used.
  
  
  RESULTS
  Intrastromal PRK resulted in no perceptible damage to the corneal epithelium or Bowman's layer either acutely or at 6 months. The corneal stroma showed multiple cavitations immediately after intrastromal PRK, which collapsed over several hours, followed by thinning of the cornea over 2 weeks. At 1 month, the stromal collagen was abnormal with surrounding hypercellularity. The endothelium showed no injury, acutely or at 6 months. No thermal effects on stromal collagen were observed at 6 months, and disruption of the lamellar pattern was not apparent after the cavitation bubbles were reabsorbed.
  
  
  CONCLUSIONS
  Intrastromal PRK can effectively remove stromal tissue without acute damage to the adjacent lamellae, epithelium, or endothelium. There is a transient cellular wound healing response associated with a transient stromal collagen abnormality at 2 weeks to 1 month, which was not apparent 2 months after the procedure.
authors.affiliation: Department of Ophthalmology, New York Eye and Ear Infirmary, New York 10003, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Habib
authors.forename: M G
authors.initials: MG
authors.lastname: Speaker
authors.forename: S A
authors.initials: SA
authors.lastname: McCormick
authors.forename: R
authors.initials: R
authors.lastname: Kaiser
mesh_terms: D000818:Animals; D002415:Cats; D003315:Cornea / Q000473:pathology; D003319:Corneal Stroma / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D007834:Lasers; D054018:Lasers, Excimer; D008855:Microscopy, Electron, Scanning; D018903:Photorefractive Keratectomy / Q000295:instrumentation / Q000379:methods; D011184:Postoperative Period; D014945:Wound Healing