title: Refractive error in children in an urban population in New Delhi.
abstract: OBJECTIVE
  To assess the prevalence of refractive error and related visual impairment in school-aged children in an urban population in New Delhi, India.
  
  
  METHODS
  Random selection of geographically defined clusters was used to identify a sample of children 5 to 15 years of age. From December 2000 through March 2001, children in 22 selected clusters were enumerated through a door-to-door survey and examined at a local facility. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy and autorefraction under cycloplegia, and examination of the anterior segment, media, and fundus. Myopia was defined as spherical equivalent refractive error of at least -0.50 D and hyperopia as +2.00 D or more. Children with reduced vision and a sample of those with normal vision underwent independent replicate examinations for quality assurance in four of the clusters.
  
  
  RESULTS
  A total of 7008 children from 3426 households were enumerated, and 6447 (92.0%) examined. The prevalence of uncorrected, baseline (presenting), and best corrected visual acuity of 20/40 or worse in the better eye was 6.4%, 4.9%, and 0.81%, respectively. Refractive error was the cause in 81.7% of eyes with vision impairment, amblyopia in 4.4%, retinal disorders in 4.7%, other causes in 3.3%, and unexplained causes in the remaining 5.9%. There was an age-related shift in refractive error from hyperopia in young children (15.6% in 5-year-olds) toward myopia in older children (10.8% in 15-year-olds). Overall, hyperopia was present in 7.7% of children and myopia in 7.4%. Hyperopia was associated with female gender. Myopia was more common in children of fathers with higher levels of education.
  
  
  CONCLUSIONS
  Reduced vision because of uncorrected refractive error is a major public health problem in urban school-aged children in India. Cost-effective strategies are needed to eliminate this easily treated cause of vision impairment.
authors.affiliation: Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute for Medical Sciences, New Delhi, India.
authors.forename: G V S
authors.initials: GV
authors.lastname: Murthy
authors.forename: Sanjeev K
authors.initials: SK
authors.lastname: Gupta
authors.forename: Leon B
authors.initials: LB
authors.lastname: Ellwein
authors.forename: Sergio R
authors.initials: SR
authors.lastname: Muñoz
authors.forename: Gopal P
authors.initials: GP
authors.lastname: Pokharel
authors.forename: Lalit
authors.initials: L
authors.lastname: Sanga
authors.forename: Damodar
authors.initials: D
authors.lastname: Bachani
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D011897:Random Allocation; D012030:Refractive Errors / Q000453:epidemiology* / Q000517:prevention & control; D017678:Sex Distribution; D014505:Urban Population / Q000706:statistics & numerical data*; D014787:Vision Tests; D014792:Visual Acuity