title: Prevalence and correction of near vision impairment at seven sites in China, India, Nepal, Niger, South Africa, and the United States.
abstract: OBJECTIVE
  To estimate the prevalence of near vision impairment and use of corrective spectacles among middle-aged and older adults in different settings and ethnic groups.
  
  
  METHODS
  Population-based, cross-sectional study.
  
  
  METHODS
  People aged ≥ 35 years were randomly selected with cluster sampling in 4 rural settings in Shunyi (China), Kaski (Nepal), Madurai (India), and Dosso (Niger); 1 semi-urban area in Durban (South Africa); and 2 urban settings in Guangzhou (China) and Los Angeles (USA). Near visual acuity (VA), with and without presenting near correction, was measured at 40 cm using a logMAR near vision tumbling E chart. Subjects with uncorrected binocular near VA ≤ 20/40 were tested with plus spheres to obtain the best-corrected binocular VA.
  
  
  RESULTS
  A total of 17 734 persons aged ≥ 35 years were enumerated and 14 805 (83.5%) were examined. The age- and sex-standardized prevalence of uncorrected near vision impairment (VA ≤ 20/40) ranged from 49% in Dosso to 60% in Shunyi and Guangzhou, 65% in Kaski and Los Angeles, and 83% in Madurai and Durban. The prevalence of near vision impairment based on best-corrected visual acuity was less than 10% in Guangzhou, Kaski, Durban, and Los Angeles, but as high as 23% in Madurai. In multiple logistic regression models, uncorrected near vision impairment was associated with older age (odds ratio [OR] = 1.14, P < .001) and female sex (OR = 1.12, P = .027), but not with educational level (OR = 1.01, P = .812). Over 90% of people in need of near refractive correction in rural settings did not have the necessary spectacles. These rates were 40% in urban settings.
  
  
  CONCLUSIONS
  By 50 years of age, the majority of people suffer from near vision impairment, most of which can be corrected optically. Over 90% of those in need of near refractive correction in rural settings do not have the necessary spectacles.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China. mingguang_he@yahoo.com
authors.forename: Mingguang
authors.initials: M
authors.lastname: He
authors.forename: Amza
authors.initials: A
authors.lastname: Abdou
authors.forename: Kovin S
authors.initials: KS
authors.lastname: Naidoo
authors.forename: Yuddha D
authors.initials: YD
authors.lastname: Sapkota
authors.forename: R D
authors.initials: RD
authors.lastname: Thulasiraj
authors.forename: Rohit
authors.initials: R
authors.lastname: Varma
authors.forename: Jialiang
authors.initials: J
authors.lastname: Zhao
authors.forename: Leon B
authors.initials: LB
authors.lastname: Ellwein
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005006:Ethnicity; D005139:Eyeglasses; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000453:epidemiology* / Q000628:therapy*; D009390:Nepal / Q000453:epidemiology; D009548:Niger / Q000453:epidemiology; D015995:Prevalence; D012424:Rural Population / Q000706:statistics & numerical data; D013019:South Africa / Q000453:epidemiology; D014481:United States / Q000453:epidemiology; D014505:Urban Population / Q000706:statistics & numerical data; D015348:Vision, Binocular / Q000502:physiology; D015354:Vision, Low / Q000453:epidemiology / Q000628:therapy; D014792:Visual Acuity / Q000502:physiology; D019987:Persons with Visual Disabilities