The Effect of Procedure Room Temperature and Humidity on LASIK Outcomes
ABSTRACT OBJECTIVE: To determine whether procedure room temperature or humidity during LASIK affect refractive outcomes in a large patient sample. DESIGN: Retrospective cohort study. PARTICIPANTS: A total of 202 394 eyes of 105 712 patients aged 18 to 75 years who underwent LASIK at an Optical Express, Inc., location in their United Kingdom and Ireland centers from January 1, 2008, to June 30, 2011, who met inclusion criteria. METHODS: Patient age, gender, flap creation technique, pre- and 1-month post-LASIK manifest refraction, and ambient temperature and humidity during LASIK were recorded. Effect size determination and univariate and multivariate analyses were performed to characterize the relationships between LASIK procedure room temperature and humidity and postoperative refractive outcome. MAIN OUTCOME MEASURES: One month post-LASIK manifest refraction. RESULTS: No clinically significant effect of procedure room temperature or humidity was found on LASIK refractive outcomes. When considering all eyes in our population, an increase of 1°C during LASIK was associated with a 0.003 diopter (D) more hyperopic refraction 1 month postoperatively, and an increase in 1% humidity was associated with a 0.0004 more myopic refraction. These effect sizes were the same or similar when considering only myopic eyes, only hyperopic eyes, and subgroups of eyes stratified by age and preoperative refractive error. CONCLUSIONS: Neither procedure room temperature nor humidity during LASIK were found to have a clinically significant relationship with postoperative manifest refraction in our population. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.
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ABSTRACT: Laser in situ keratomileusis (LASIK) is one of the dominant procedures for the surgical correction of refractive errors. Meteorotropic reaction has been described regarding the field of ophthalmology. This study was thus initiated to assess the impact of air pressure and wind speed on the refractive and visual outcome of LASIK in myopic eyes. Our 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 mean preoperative refractive spherical equivalent (SE) of -3.88 ± 1.85 diopters (D). Two subgroups were defined, which had undergone surgery either during meteorological winter or summer. Manifest refraction, uncorrected and corrected visual acuity were assessed pre- and post-operatively. We applied robust regression analysis with efficiency index (EI), safety index, and postoperative SE (D) as dependent variables. 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 low to moderate air-pressure. This was confirmed by robust regression analysis. Moderate to high wind speed was related to more appropriate postoperative SE. No change by more than one line on logMar scale was obtained. Although being statistically significant, there is no clinically relevant difference in outcome of LASIK, which demonstrates its highly standardized quality. Prospective, longitudinal studies are warranted to address meteorotropic reactions through evaluating individual risk profiles.International Ophthalmology 02/2014; DOI:10.1007/s10792-014-9923-y
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ABSTRACT: Purpose To examine the impact of temperature and sunlight duration on refractive and visual outcome of laser-assisted in situ keratomileusis (LASIK) in myopic eyes. Setting University Medical Center Hamburg-Eppendorf, Germany, and Care Vision Refractive Centers, Germany. Design 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. Conclusion 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.Clinical Ophthalmology 06/2014; 8(8):1129–1137. DOI:10.2147/OPTH.S57717
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ABSTRACT: Objetivo Analizar el efecto de los cambios estacionales en la refracción residual, transcurrido un año tras cirugía refractiva corneal empleando el sistema láser SCHWIND AMARIS. Métodos Se revisaron retrospectivamente 5.740 tratamientos consecutivos. En todos los casos se planificaron los tratamientos asféricos con el software Custom Ablation Manager, realizándose las ablaciones con el láser excímer SCHWIND AMARIS (SCHWIND eye-tech-solutions). Se evaluaron los resultados estacionales en términos de refracción residual, estratificada por mes de tratamiento, y por estación del año. Se utilizó la prueba de t de Student para comparar los valores estratificados con los globales en el análisis estadístico. Resultados Los tratamientos realizados en abril, junio, agosto, septiembre y octubre reflejaron infracorrecciones relativas del equivalente esférico (EE) (-0,09D), mientras que los tratamientos realizados en enero, febrero y marzo mostraron unas sobrecorrecciones relativas del EE (+0,13D). De igual modo, los tratamientos realizados en primavera y verano reflejaron infracorrecciones relativas del EE (-0,04D), mientras que los tratamientos realizados en invierno mostraron sobrecorrecciones relativas del EE (+0,10D). Conclusiones Se observaron diferencias estacionales en los resultados refractivos en una población a gran escala. El efecto de estas variables ambientales sobre los resultados refractivos justifica una evaluación adicional.Journal of Optometry 07/2014; DOI:10.1016/j.optom.2013.12.004