title: Prevalence and risk factors for refractive errors in Indians: the Singapore Indian Eye Study (SINDI).
abstract: OBJECTIVE
  To determine the prevalence and risk factors for refractive errors in middle-aged to elderly Singaporeans of Indian ethnicity.
  
  
  METHODS
  A population-based, cross-sectional study of Indians aged over 40 years of age residing in Southwestern Singapore was conducted. An age-stratified (10-year age group) random sampling procedure was performed to select participants. Refraction was determined by autorefraction followed by subjective refraction. Myopia was defined as spherical equivalent (SE) < -0.50 diopters (D), high myopia as SE < -5.00 D, astigmatism as cylinder < -0.50 D, hyperopia as SE > 0.50 D, and anisometropia as SE difference > 1.00 D. Prevalence was adjusted to the 2000 Singapore census.
  
  
  RESULTS
  Of the 4497 persons eligible to participate, 3400 (75.6%) were examined. Complete data were available for 2805 adults with right eye refractive error and no prior cataract surgery. The age-adjusted prevalence was 28.0% (95% confidence interval [CI], 25.8-30.2) for myopia and 4.1% (95% CI, 3.3-5.0) for high myopia. There was a U-shaped relationship between myopia and increasing age. The age-adjusted prevalence was 54.9% (95% CI, 52.0-57.9) for astigmatism, 35.9% (95% CI, 33.7-38.3) for hyperopia, and 9.8% (95% CI, 8.6-11.1) for anisometropia. In a multiple logistic regression model, adults who were female, younger, taller, spent more time reading and writing per day, or had astigmatism were more likely to be myopic. Adults who were older or had myopia or diabetes mellitus had higher risk of astigmatism.
  
  
  CONCLUSIONS
  In Singapore, the prevalence of myopia in Indian adults is similar to those in Malays, but lower than those in Chinese. Risk factors for myopia are similar across the three ethnic groups in Singapore.
authors.affiliation: Department of Epidemiology and Public Health, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Chen-Wei
authors.initials: CW
authors.lastname: Pan
authors.forename: Tien-Yin
authors.initials: TY
authors.lastname: Wong
authors.forename: Raghavan
authors.initials: R
authors.lastname: Lavanya
authors.forename: Ren-Yi
authors.initials: RY
authors.lastname: Wu
authors.forename: Ying-Feng
authors.initials: YF
authors.lastname: Zheng
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Lin
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
authors.forename: Tin
authors.initials: T
authors.lastname: Aung
authors.forename: Seang-Mei
authors.initials: SM
authors.lastname: Saw
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000706:statistics & numerical data*; D001824:Body Constitution; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007194:India / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012030:Refractive Errors / Q000208:ethnology*; D012307:Risk Factors; D017678:Sex Distribution; D012846:Singapore / Q000453:epidemiology; D011795:Surveys and Questionnaires; D014792:Visual Acuity / Q000502:physiology