title: Changes in central corneal thickness after laser in situ keratomileusis and photorefractive keratectomy.
abstract: OBJECTIVE
  To evaluate changes in corneal thickness after laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) in eyes with the same preoperative refraction, correlate these changes to postoperative refractive outcomes, and compare corneal healing process in a standardized subset of patients.
  
  
  METHODS
  Central corneal thickness was measured by contact ultrasound pachymetry in 14 eyes of 8 patients with preoperative myopia of -6.00 D who had LASIK, and in 14 eyes of 8 patients with the same preoperative refractive error who had PRK. Measurements were taken preoperatively, and 1 week, 3, and 6 months after surgery. Data were evaluated and compared using the paired Student t-test and Pearson correlation coefficient.
  
  
  RESULTS
  Mean preoperative central corneal thickness in the LASIK group was 549.14 +/- 37.4 microm, and in the PRK group, 552.64 +/- 34.9 microm. At 1-week postoperatively, mean central corneal thickness in the LASIK eyes was 467.28 +/- 29 microm and in the PRK eyes, 473.85 +/- 39.2 microm; at 6 months, central corneal thickness had increased in both groups compared to the 1-week values; LASIK eyes had a mean central corneal thickness of 481.42 +/- 23.0 microm and PRK, 481.50 +/- 35.3 microm. Mean postoperative refraction after 6 months was -0.48 +/- 0.30 D in the LASIK group and -0.67 +/- 0.35 D in the PRK group.
  
  
  CONCLUSIONS
  Increase in central corneal thickness between 1 week and 6 months postoperatively occurred in both LASIK and PRK eyes, but differences were not statistically significant. No statistically significant differences were found in myopic regression between the two patient groups.
authors.affiliation: Department of Ophthalmology, P.J. Safarik University Hospital, Kosice, Slovak Republic. ikozak_2000@yahoo.com
authors.forename: Igor
authors.initials: I
authors.lastname: Kozak
authors.forename: Marek
authors.initials: M
authors.lastname: Hornak
authors.forename: Tomas
authors.initials: T
authors.lastname: Juhas
authors.forename: Arvind
authors.initials: A
authors.lastname: Shah
authors.forename: E Franklin
authors.initials: EF
authors.lastname: Rawlings
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000601:surgery; D003315:Cornea / Q000473:pathology* / Q000601:surgery; D003316:Corneal Diseases / Q000209:etiology*; D019781:Corneal Topography; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D054018:Lasers, Excimer; D008297:Male; D009216:Myopia / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000009:adverse effects*; D011183:Postoperative Complications; D011446:Prospective Studies; D012029:Refraction, Ocular; D016896:Treatment Outcome; D014792:Visual Acuity