title: Do outside temperature and sunlight duration influence the outcome of laser refractive surgery? Results from the Hamburg Weather Study.
abstract: OBJECTIVE
  To examine the impact of temperature and sunlight duration on refractive and visual outcome of laser-assisted in situ keratomileusis (LASIK) in myopic eyes.
  
  
  METHODS
  University Medical Center Hamburg-Eppendorf, Germany, and Care Vision Refractive Centers, Germany.
  
  
  METHODS
  Retrospective, cross-sectional data analysis.
  
  
  METHODS
  This study comprised 1,052 eyes of 1,052 consecutive myopic patients (419 males, 633 females; mean age at surgery 35.0±9.0 years) with a mean preoperative refractive spherical equivalent (SE) of -3.88±1.85 diopters (D). Two subgroups were defined, comprising patients undergoing surgery during either meteorological winter or summer. Manifest refraction, uncorrected, and corrected distant visual acuity (UDVA and CDVA) were assessed pre- and postoperatively. We applied robust regression analysis with efficiency index (EI), safety index (SI), and postoperative SE (in D) as dependent variables.
  
  
  RESULTS
  At the 1-month (33.0±5.0 days) follow-up, the mean postoperative SE was -0.18±0.44 D. Bivariate comparisons showed that statistically significant better EI was related to days with lower temperature. We obtained a significant difference for SI which suggested that low temperature had a positive influence on SI. No change by more than one line on LogMAR scale was obtained.
  
  
  CONCLUSIONS
  Although being statistically significant, there was no clinically relevant difference in the outcome of LASIK, which demonstrates its highly standardized quality. Prospective, longitudinal studies are warranted to address meteorotropic reactions through evaluating defined meteorological parameters.
authors: Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Germany.
authors: Ines
authors: I
authors: Neuhaus-Richard
authors: Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Germany.
authors: Andreas
authors: A
authors: Frings
authors: Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Germany.
authors: Isabel Caroline
authors: IC
authors: Görsch
authors: Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Germany.
authors: Vasyl
authors: V
authors: Druchkiv
authors: Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Germany ; Care Vision Refractive Centers, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors: Toam
authors: T
authors: Katz
authors: Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Germany ; Care Vision Refractive Centers, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors: Stephan Johannes
authors: SJ
authors: Linke
authors: Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Germany.
authors: Gisbert
authors: G
authors: Richard
keywords: LASIK; refractive surgery; sunlight; temperature; weather