title: [Biomechanical study of corneal stability after photorefractive keratectomy].
abstract: BACKGROUND
  Photorefraktive keratectomy (PRK) is the most frequent refractive surgical procedure worldwide. The central corneal thickness is reduced due to removal of the anterior stroma, including Bowman's layer, with a laser beam. This procedure results in considerable alterations of the corneal structure. What does this mean for the mechanical properties of the cornea?
  
  
  METHODS
  Intraocular pressure was increased via a 180 degrees tilt. Before and during this procedure, corneal topography was measured by photokeratoscopy. We examined 26 patients after PRK and 25 controls who had not undergone any surgical procedure.
  
  
  RESULTS
  The corneal center flattened by 0.038 +/- 0.05 dpt (P > 0.05) in the PRK patients and by 0.187 +/- 0.045 dpt (P < 0.05) in the control group. PRK patients within 1 year after operation showed a minimal central corneal steepening, whereas PRK patients after more than 1 year showed a reaction similar to that in normal corneas (P < 0.05).
  
  
  CONCLUSIONS
  Corneal stability is altered after PRK. After 1 year corneal stability seems to normalize due to stromal remodelling.
authors.affiliation: Universitäts-Augenklinik, Hamburg Eppendorf.
authors.forename: A
authors.initials: A
authors.lastname: Böhm
authors.forename: M
authors.initials: M
authors.lastname: Kohlhaas
authors.forename: R C
authors.initials: RC
authors.lastname: Lerche
authors.forename: J O
authors.initials: JO
authors.lastname: Hjortdal
authors.forename: N
authors.initials: N
authors.lastname: Ehlers
authors.forename: J
authors.initials: J
authors.lastname: Draeger
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D003315:Cornea / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D018903:Photorefractive Keratectomy; D011183:Postoperative Complications / Q000503:physiopathology*; D012016:Reference Values; D012029:Refraction, Ocular
vernacular_title: Biomechanische Untersuchung der Hornhautstabilität nach photorefraktiver Keratektomie.