title: Acute corneal endothelial changes after laser in situ keratomileusis.
abstract: OBJECTIVE
  To report the acute effects of laser in situ keratomileusis (LASIK) on the corneal endothelium.
  
  
  METHODS
  Twenty eyes of 10 consecutive patients (mean age, 38.1 +/- 10.84 years) underwent bilateral simultaneous LASIK for myopic astigmatism (spherical equivalent ranging from -1.75 to -7.13 diopters) without any complications. Each eye was evaluated by slit-lamp biomicroscopy and noncontact specular microscopy preoperatively, within 15 minutes after LASIK and 1 day after surgery. Specular microscopy images were then analyzed to calculate endothelial cell density (ECD), coefficient of variation (CV) of cell size, and percentage of hexagonal cells.
  
  
  RESULTS
  All corneas demonstrated marked alterations in endothelial cell morphology by slit-lamp biomicroscopy within 15 minutes after surgery that resolved by the first postoperative day. Central corneal endothelial analysis by noncontact specular microscopy confirmed pleomorphism with definite loss of hexagonality. Mean ECD was calculated to be 2,816.3 +/- 286.02 cells/mm(2) preoperatively, 2,750.85 +/- 327.95 cells/mm(2) on day 0 (p = 0.395), and 2,810.55 +/- 218.48 cells/mm(2) on day 1 (p = 0.461). Mean CV was 32.65 +/- 7.29 preoperatively, 34.4 +/- 6.19 on day 0 (p = 0.412), and 30.9 +/- 5.54 on day 1 (p = 0.067). Mean percentage of hexagonal cells was 63.35 +/- 10.76 preoperatively, 47.55 +/- 9.69 on day 0 (p = 0.000009), and 60 +/- 9.3 on day 1 (p = 0.00003).
  
  
  CONCLUSIONS
  Qualitative and quantitative changes in endothelial cell morphology (i.e., decreased endothelial cell hexagonality) demonstrate that LASIK does induce an acute effect on the corneal endothelium that may represent transient endothelial cell edema.
authors.affiliation: Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, USA. terry.kim@duke.edu
authors.forename: T
authors.initials: T
authors.lastname: Kim
authors.forename: A L
authors.initials: AL
authors.lastname: Sorenson
authors.forename: S
authors.initials: S
authors.lastname: Krishnasamy
authors.forename: A N
authors.initials: AN
authors.lastname: Carlson
authors.forename: H F
authors.initials: HF
authors.lastname: Edelhauser
mesh_terms: D000208:Acute Disease; D000328:Adult; D001251:Astigmatism / Q000473:pathology / Q000601:surgery*; D002452:Cell Count; D015715:Corneal Edema / Q000209:etiology / Q000473:pathology; D004728:Endothelium, Corneal / Q000473:pathology*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000473:pathology / Q000601:surgery*; D011183:Postoperative Complications / Q000473:pathology*; D011446:Prospective Studies