title: Change in intraocular pressure measurement after myopic LASEK: a study evaluating goldmann, pascal and applanation resonance tonometry.
abstract: OBJECTIVE
  To prospectively evaluate 3 tonometry methods--the gold standard, Goldmann applanation tonometry, a new method, Pascal dynamic contour tonometry (PDCT), and a method under development, applanation resonance tonometry (ART)--with respect to intraocular pressure (IOP) measurements before, 3 and 6 months after laser-assisted subepithelial keratectomy (LASEK).
  
  
  METHODS
  One randomly assigned eye of each of 53 healthy individuals, who underwent LASEK surgery for myopia was studied. Visual acuity, central corneal thickness, corneal curvature, and IOP were measured at each visit. Six IOP measurements/methods with 5 minutes pause between methods were performed.
  
  
  RESULTS
  All tonometry methods measured a significantly lower IOP after LASEK correction by a mean of -3.1 diopters. The IOP reduction was largest after 6 months for Goldmann applanation tonometry (-1.7 ± 1.8 mm Hg) followed by ARTstat (-1.2 ± 1.5 mm Hg), PDCT (-1.1 ± 1.6 mm Hg), and ARTdyn (-1.0 ± 1.5 mm Hg). The reduction of IOP did not differ significantly between different methods (P=0.11). There was a significant further reduction of measured IOP for PDCT between 3 and 6 months (-0.5 ± 1.0 mm Hg). Uncorrected visual acuity improved significantly between 3 and 6 months postoperatively from 1.32 ± 0.28 to 1.43 ± 0.27.
  
  
  CONCLUSIONS
  All tonometry methods measured a significant, but low, reduction of IOP 3 and 6 months after LASEK. Further change in visual acuity and IOP measurements between 3 and 6 months suggest a still ongoing postoperative process.
authors.affiliation: Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden. gauti.johannesson@ophthal.umu.se
authors.forename: Gauti
authors.initials: G
authors.lastname: Jóhannesson
authors.forename: Per
authors.initials: P
authors.lastname: Hallberg
authors.forename: Anders
authors.initials: A
authors.lastname: Eklund
authors.forename: Timo
authors.initials: T
authors.lastname: Koskela
authors.forename: Christina
authors.initials: C
authors.lastname: Lindén
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D049008:Keratectomy, Subepithelial, Laser-Assisted; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D011184:Postoperative Period; D057234:Preoperative Period; D011446:Prospective Studies; D014065:Tonometry, Ocular / Q000379:methods*; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult