title: Population-based assessment of refractive error in India: the Andhra Pradesh eye disease study.
abstract: OBJECTIVE
  To assess the prevalence, distribution, and demographic associations of refractive error in the population of the southern Indian state of Andhra Pradesh.
  
  
  METHODS
  From 94 clusters in one urban and three rural areas of Andhra Pradesh, 11 786 persons of all ages were sampled using a stratified, random, cluster, systematic sampling strategy in the Andhra Pradesh Eye Disease Study, a population-based cross-sectional study. A total of 10 293 people underwent an interview and detailed dilated eye examination. Refraction was performed by ophthalmic personnel trained in the study procedures. Objective refraction under cycloplegia was assessed for participants < or = 15 years of age and subjective refraction for those > 15 years of age. Myopia was defined as spherical equivalent worse than -0.50 D and hyperopia as spherical equivalent worse than +0.50 D.
  
  
  RESULTS
  In the participants < or = 15 years of age, the prevalence of myopia was 3.19% (95% confidence interval [CI] 2.24-4.13%) and of hyperopia was 62.62% (95% CI 57.10-68.13%). In this age group, myopia increased with increasing age and was more prevalent in the urban study area, and hyperopia prevalence was greater in the participants < 10 years of age. In participants > 15 years of age, the prevalence of myopia was 19.45% (95% CI 17.88-21.02%) and of hyperopia was 8.38% (95% CI 6.91-9.85%). Myopia and hyperopia increased with increasing age. Myopia was more common in males, those with education higher than class 12, those with nuclear cataract, and those living in rural study areas. Hyperopia was more common in females, those with any level of formal education, and those living in the urban area and in the well-off rural study area.
  
  
  CONCLUSIONS
  There is significant refractive error in this population. These data on the distribution and associations of refractive error can be useful for the planning of refractive eye-care services.
authors.affiliation: International Centre forAdvancement of Rural Eye Care, LV Prasad Eye Institute, and Centre for Social Services, Administrative Staff College of India, Hyderabad, India. rakhi@asci.org.in
authors.forename: Rakhi
authors.initials: R
authors.lastname: Dandona
authors.forename: Lalit
authors.initials: L
authors.lastname: Dandona
authors.forename: Marmamula
authors.initials: M
authors.lastname: Srinivas
authors.forename: Pyda
authors.initials: P
authors.lastname: Giridhar
authors.forename: Catherine A
authors.initials: CA
authors.lastname: McCarty
authors.forename: Gullapalli N
authors.initials: GN
authors.lastname: Rao
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D007223:Infant; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012030:Refractive Errors / Q000453:epidemiology*; D012424:Rural Population / Q000706:statistics & numerical data; D017678:Sex Distribution; D014505:Urban Population / Q000706:statistics & numerical data; D014787:Vision Tests