title: Visual acuity in a community-dwelling Japanese population and factors associated with visual impairment.
abstract: OBJECTIVE
  The aim of this study was to describe the distribution of visual acuity and investigate the predictors of visual impairment in a Japanese population.
  
  
  METHODS
  Best-corrected visual acuity was measured in 2263 subjects aged 40-79 years randomly selected from a local community. Relations between visual impairment and possible risk factors were investigated.
  
  
  RESULTS
  Among these subjects, 41 individuals (1.8%) were identified as visually impaired (best-corrected visual acuity in the better eye <0.5). Both sexes in the older age groups had a higher frequency of visual impairment (Mantel-Haenszel chi-square test: P<0.001). A multiple logistic regression indicated that an increase in age of 10 years [odds ratio (OR) 3.9; 95% confidence interval (CI) 2.3-6.7] and myopia (OR 2.9; 95%CI 1.4-6.0) were independent risk factors for visual impairment. Individuals with the highest level of education (college or higher) had a lower risk of visual impairment (OR 0.1; 95%CI 0-0.7) compared to individuals with the lowest level of education.
  
  
  CONCLUSIONS
  As expected, visual impairment increased with advancing age, although the prevalence of visual impairment in our population was lower than in other surveys. Racial and regional differences and differences in study design may be responsible for discrepancies between surveys. It is noteworthy that myopia was a significant risk factor for visual impairment, although the reasons for this association are uncertain and need further investigation.
authors.affiliation: Department of Ophthalmology, Nagoya University, School of Medicine, Nagoya, Japan. iwano@mc.neweb.ne.jp
authors.forename: Makiko
authors.initials: M
authors.lastname: Iwano
authors.forename: Hideki
authors.initials: H
authors.lastname: Nomura
authors.forename: Fujiko
authors.initials: F
authors.lastname: Ando
authors.forename: Naoakira
authors.initials: N
authors.lastname: Niino
authors.forename: Yozo
authors.initials: Y
authors.lastname: Miyake
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimokata
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D001766:Blindness / Q000453:epidemiology*; D005260:Female; D006306:Health Surveys; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011897:Random Allocation; D012111:Residence Characteristics; D012307:Risk Factors; D017678:Sex Distribution; D015354:Vision, Low / Q000453:epidemiology*; D014792:Visual Acuity / Q000502:physiology*; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*