title: Retinal nerve fiber layer changes after LASIK evaluated with optical coherence tomography.
abstract: OBJECTIVE
  To determine whether the increase in intraocular pressure (IOP) during LASIK suction can induce a decrease in retinal nerve fiber layer thickness assessed by optical coherence tomography (OCT).
  
  
  METHODS
  Nineteen patients (38 eyes) were enrolled in the study. Intraocular pressure was normal at all pre- and postoperative examinations. Retinal nerve fiber layer thickness was measured using OCT-3 Stratus prior to and 1 week and 3 months after LASIK. Laser in situ keratomileusis was performed using the Bausch & Lomb Hansatome microkeratome and the NIDEK EC-5000 excimer laser. Optical coherence tomography mean retinal nerve fiber layer thickness values before and after LASIK were compared using the Student paired t test.
  
  
  RESULTS
  Mean patient age was 27.8 years (range: 18 to 33 years). Mean preoperative spherical equivalent refractive error was -4.9 diopters (D) (range: -2.0 to -8.5 D). Mean time of microkeratome suction was 30 seconds (range: 20 to 50 seconds). Preoperatively, the mean retinal nerve fiber layer thickness obtained by OCT was 104.2+/-9.0 microm; at 1 week postoperatively the mean thickness was 101.9+/-6.9 microm, and 106.7+/-6.1 microm at 3 months postoperatively. Mean retinal nerve fiber layer thicknesses obtained by OCT were not significantly different between preoperative and 1 week and 3 months after LASIK (P > or = .05).
  
  
  CONCLUSIONS
  Laser in situ keratomileusis performed on young myopic patients does not have a significant effect on retinal nerve fiber layer thickness determined by OCT. Further studies are required to reveal the risk of possible optic nerve or retinal nerve fiber layer damage by elevated IOP during LASIK.
authors.affiliation: International Research Eye Clinic New Vision, Moscow, Russia.
authors.forename: Dmitriy D
authors.initials: DD
authors.lastname: Dementyev
authors.forename: Vyacheslav V
authors.initials: VV
authors.lastname: Kourenkov
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Rodin
authors.forename: Tatyana L
authors.initials: TL
authors.lastname: Fadeykina
authors.forename: Tatyana E
authors.initials: TE
authors.lastname: Diaz Martines
mesh_terms: D000293:Adolescent; D000328:Adult; D005500:Follow-Up Studies; D006801:Humans; D007429:Intraocular Pressure; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D009216:Myopia / Q000473:pathology / Q000601:surgery*; D009412:Nerve Fibers / Q000473:pathology*; D011184:Postoperative Period; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012307:Risk Factors; D041623:Tomography, Optical Coherence