title: Change in keratometry after myopic laser in situ keratomileusis and photorefractive keratectomy.
abstract: OBJECTIVE
  To compare the change in keratometry (K), spherical equivalent (SE), and visual acuity after myopic laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK).
  
  
  METHODS
  Academic tertiary care center.
  
  
  METHODS
  Retrospective review.
  
  
  METHODS
  The postoperative K, SE, and uncorrected and corrected distance visual acuities were measured 6 months, 9 months, 1 year, 2 years, 3 years, 4 to 5 years, 6 to 7 years, and 8+ years postoperatively. A difference (Δ) for each variable was calculated from its 6-month postoperative baseline. The rates of change were grouped based on the magnitude of myopic correction (0.00 to 2.99 diopters [D]; 3.00 to 5.99 D; 6.00 to 8.99 D), type of surgery (LASIK versus PRK), and age (<34 years; 34 to 45 years; >45 years).
  
  
  RESULTS
  Statistically significant differences were found in the rates of change between low and moderate corrections to high corrections for ΔKavg (P=.0472 and P=.0091, respectively) and ΔSE (both P<.0001). Statistically significant differences were found in the rate of change in ΔKavg between all 3 ages groups (P=.0330, P=.0051, and P<.0001) and in ΔSE between ages less than 34 years and 34 to 45 years to ages over 45 years (P=.0158 and P=.0015, respectively). There was no significant difference in the rate of change in ΔKavg and ΔSE between LASIK and PRK (P=.3599 and P=.9403, respectively).
  
  
  CONCLUSIONS
  There was keratometric and refractive regression for myopic LASIK, with the rate of regression depending on treatment magnitude and age.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: From the John A. Moran Eye Center (Kim, Christiansen, Moshifar), University of Utah, Salt Lake City, Utah, and the Ruiz Department of Ophthalmology and Visual Science (Kim), University of Texas Medical School at Houston, and the Robert Cizik Eye Clinic (Kim), Houston, Texas, USA.
authors.forename: Gene
authors.initials: G
authors.lastname: Kim
authors.affiliation: From the John A. Moran Eye Center (Kim, Christiansen, Moshifar), University of Utah, Salt Lake City, Utah, and the Ruiz Department of Ophthalmology and Visual Science (Kim), University of Texas Medical School at Houston, and the Robert Cizik Eye Clinic (Kim), Houston, Texas, USA.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Christiansen
authors.affiliation: From the John A. Moran Eye Center (Kim, Christiansen, Moshifar), University of Utah, Salt Lake City, Utah, and the Ruiz Department of Ophthalmology and Visual Science (Kim), University of Texas Medical School at Houston, and the Robert Cizik Eye Clinic (Kim), Houston, Texas, USA. Electronic address: majid.moshirfar@hsc.utah.edu.
authors.forename: Majid
authors.initials: M
authors.lastname: Moshirfar
mesh_terms: D000328:Adult; D003315:Cornea / Q000473:pathology*; D005500:Follow-Up Studies; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000379:methods*; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D014792:Visual Acuity / Q000502:physiology