title: Variation in the effectiveness of refractive surgery during the year: results from the Hamburg Weather Study.
abstract: OBJECTIVE
  To examine the impact of seasonality on the refractive and visual outcomes of laser in situ keratomileusis (LASIK) in myopic eyes.
  
  
  METHODS
  Department of Ophthalmology and Care Vision Refractive Centers, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
  
  
  METHODS
  Retrospective cross-sectional data analysis.
  
  
  METHODS
  Two subgroups were defined. The first comprised patients having surgery during meteorological winter and the second, patients having surgery during meteorological summer. The manifest refraction and uncorrected and corrected visual acuities were assessed preoperatively and postoperatively. Robust regression analysis was applied with the efficacy index, safety index, and postoperative SE as dependent variables.
  
  
  RESULTS
  This study comprised 1052 eyes of 1052 consecutive myopic patients (419 men, 633 women; mean age at surgery 35.0 years ± 9.0 [SD]) with a mean preoperative refractive spherical equivalent (SE) of -3.88 ± 1.85 diopters (D). At the 1-month follow-up (mean 33.0 ± 5.0 days), the mean postoperative SE was -0.18 ± 0.44 D. The efficacy index was 0.023 higher in eyes with refractive surgery during summer than in eyes treated during winter (P=.032), indicating less efficacy during winter. The differences in the safety index and postoperative SE between summer and winter were not statistically significant. No eye had a change of more than 1 line on the logMAR scale (corrected distance visual acuity).
  
  
  CONCLUSIONS
  Although the difference in the efficacy index was statistically significant, the difference in the outcomes of LASIK was not clinically relevant, which shows the procedure's highly standardized reliability. Prospective longitudinal studies are warranted to address meteorotropic reactions by evaluating defined meteorological parameters.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors: From the Department of Ophthalmology (Neuhaus-Richard, Frings, Görsch, Druchkiv, Katz, Linke, Richard) and Care Vision Refractive Centers (Katz, Linke), University Medical Center Hamburg-Eppendorf, and the Meteorological Institute (Ament), University of Hamburg, Hamburg, Germany.
authors: Ines
authors: I
authors: Neuhaus-Richard
authors: From the Department of Ophthalmology (Neuhaus-Richard, Frings, Görsch, Druchkiv, Katz, Linke, Richard) and Care Vision Refractive Centers (Katz, Linke), University Medical Center Hamburg-Eppendorf, and the Meteorological Institute (Ament), University of Hamburg, Hamburg, Germany. Electronic address: a.frings@uke.de.
authors: Andreas
authors: A
authors: Frings
authors: From the Department of Ophthalmology (Neuhaus-Richard, Frings, Görsch, Druchkiv, Katz, Linke, Richard) and Care Vision Refractive Centers (Katz, Linke), University Medical Center Hamburg-Eppendorf, and the Meteorological Institute (Ament), University of Hamburg, Hamburg, Germany.
authors: Felix
authors: F
authors: Ament
authors: From the Department of Ophthalmology (Neuhaus-Richard, Frings, Görsch, Druchkiv, Katz, Linke, Richard) and Care Vision Refractive Centers (Katz, Linke), University Medical Center Hamburg-Eppendorf, and the Meteorological Institute (Ament), University of Hamburg, Hamburg, Germany.
authors: Isabel Caroline
authors: IC
authors: Görsch
authors: From the Department of Ophthalmology (Neuhaus-Richard, Frings, Görsch, Druchkiv, Katz, Linke, Richard) and Care Vision Refractive Centers (Katz, Linke), University Medical Center Hamburg-Eppendorf, and the Meteorological Institute (Ament), University of Hamburg, Hamburg, Germany.
authors: Vasyl
authors: V
authors: Druchkiv
authors: From the Department of Ophthalmology (Neuhaus-Richard, Frings, Görsch, Druchkiv, Katz, Linke, Richard) and Care Vision Refractive Centers (Katz, Linke), University Medical Center Hamburg-Eppendorf, and the Meteorological Institute (Ament), University of Hamburg, Hamburg, Germany.
authors: Toam
authors: T
authors: Katz
authors: From the Department of Ophthalmology (Neuhaus-Richard, Frings, Görsch, Druchkiv, Katz, Linke, Richard) and Care Vision Refractive Centers (Katz, Linke), University Medical Center Hamburg-Eppendorf, and the Meteorological Institute (Ament), University of Hamburg, Hamburg, Germany.
authors: Stephan Johannes
authors: SJ
authors: Linke
authors: From the Department of Ophthalmology (Neuhaus-Richard, Frings, Görsch, Druchkiv, Katz, Linke, Richard) and Care Vision Refractive Centers (Katz, Linke), University Medical Center Hamburg-Eppendorf, and the Meteorological Institute (Ament), University of Hamburg, Hamburg, Germany.
authors: Gisbert
authors: G
authors: Richard
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002980:Climate; D003430:Cross-Sectional Studies; D005260:Female; D005843:Geography; D005858:Germany; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D012029:Refraction, Ocular / Q000502:physiology*; D012189:Retrospective Studies; D012621:Seasons; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult