title: Asymmetric refraction in an older population: the Blue Mountains Eye Study.
abstract: OBJECTIVE
  To describe prevalence and associations of asymmetric refraction in an older population.
  
  
  METHODS
  All participants in the Blue Mountains Eye Study had comprehensive eye examinations, including refraction. Spherical equivalent (SEq = sum sphere +.5 cylinder), in diopters, defined refractive error. Refractive asymmetry was assessed in phakic participants; anisometropia was defined as > or =1.0 diopters SEq difference between eyes.
  
  
  RESULTS
  Anisometropia was present in 14.7% of participants. Mean refractive asymmetry (in diopters) in persons aged <60 years was 0.43; 60 to 69 years, 0.51; 70 to 79 years, 0.72; and 80+ years, 0.88. Prevalence and severity of anisometropia increased with age (P <.001), increasing ametropia or astigmatism. Associations included older age, cataract, and increasing ametropia. Myopic participants >-3.0 diopters had the highest anisometropia prevalence.
  
  
  CONCLUSIONS
  Refractive asymmetry was associated with age, increasing ametropia, and cataract.
authors.affiliation: University of Sydney Department of Ophthalmology, Centre for Vision Research, Westmead Hospital and the Westmead Millennium and Save Sight Institutes, Westmead NSW, Australia.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Guzowski
authors.forename: Samantha
authors.initials: S
authors.lastname: Fraser-Bell
authors.forename: Elena
authors.initials: E
authors.lastname: Rochtchina
authors.forename: Jie Jin
authors.initials: JJ
authors.lastname: Wang
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D015858:Anisometropia / Q000453:epidemiology* / Q000209:etiology; D002386:Cataract / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009517:New South Wales / Q000453:epidemiology; D015995:Prevalence; D012029:Refraction, Ocular