title: Corneal barrier function, tear film stability, and corneal sensation after photorefractive keratectomy and laser in situ keratomileusis.
abstract: OBJECTIVE
  To compare corneal sensation, corneal barrier function, tear secretion, and tear film stability after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK).
  
  
  METHODS
  Prospective, nonrandomized clinical trial.
  
  
  METHODS
  In a prospective study, 28 eyes of 15 patients underwent PRK and 115 eyes of 59 patients underwent LASIK to correct myopia. Corneal sensation, corneal epithelial barrier function, tear secretion, and tear film stability were examined preoperatively and 1 week and 1, 3, 6, and 12 months postsurgery.
  
  
  RESULTS
  Both PRK and LASIK significantly compromised corneal sensation, increased epithelial barrier function, reduced tear secretion, and deteriorated tear film stability (P < .05, Wilcoxon signed-rank test). Deterioration of corneal sensation was significantly greater after LASIK than after PRK by 3 months postoperatively (P < .05, Wilcoxon rank sum test). Increases in corneal epithelial permeability were more prolonged after LASIK than after PRK. A significant intergroup difference in permeability was observed 1 month after surgery (P < .01). Tear breakup time was significantly shorter in the LASIK group than in the PRK group up to 3 months after surgery (P < .045).
  
  
  CONCLUSIONS
  LASIK induces greater and more prolonged damage to corneal sensation, corneal barrier function, and tear film stability than PRK.
authors.affiliation: Meiwakai Medical Foundation, Miyata Eye Hospital, Miyazaki, Japan.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Nejima
authors.forename: Kazunori
authors.initials: K
authors.lastname: Miyata
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Tanabe
authors.forename: Fumiki
authors.initials: F
authors.lastname: Okamoto
authors.forename: Takahiro
authors.initials: T
authors.lastname: Hiraoka
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kiuchi
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Oshika
mesh_terms: D000293:Adolescent; D000328:Adult; D001692:Biological Transport / Q000502:physiology; D003315:Cornea / Q000502:physiology*; D019573:Epithelium, Corneal / Q000502:physiology*; D015590:Fluorophotometry; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology* / Q000601:surgery; D018903:Photorefractive Keratectomy; D011446:Prospective Studies; D012677:Sensation / Q000502:physiology*; D013666:Tears / Q000378:metabolism*