title: Age-related prevalence and met need for correctable and uncorrectable near vision impairment in a multi-country study.
abstract: OBJECTIVE
  To estimate the prevalence, potential determinants, and proportion of met need for near vision impairment (NVI) correctable with refraction approximately 2 years after initial examination of a multi-country cohort.
  
  
  METHODS
  Population-based, prospective cohort study.
  
  
  METHODS
  People aged ≥35 years examined at baseline in semi-rural (Shunyi) and urban (Guangzhou) sites in China; rural sites in Nepal (Kaski), India (Madurai), and Niger (Dosso); a semi-urban site (Durban) in South Africa; and an urban site (Los Angeles) in the United States.
  
  
  METHODS
  Near visual acuity (NVA) with and without current near correction was measured at 40 cm using a logarithm of the minimum angle of resolution near vision tumbling E chart. Participants with uncorrected binocular NVA ≤20/40 were tested with plus sphere lenses to obtain best-corrected binocular NVA.
  
  
  METHODS
  Prevalence of total NVI (defined as uncorrected NVA ≤20/40) and NVI correctable and uncorrectable to >20/40, and current spectacle wearing among those with bilateral NVA ≤20/63 improving to >20/40 with near correction (met need).
  
  
  RESULTS
  Among 13 671 baseline participants, 10 533 (77.2%) attended the follow-up examination. The prevalence of correctable NVI increased with age from 35 to 50-60 years and then decreased at all sites. Multiple logistic regression modeling suggested that correctable NVI was not associated with gender at any site, whereas more educated persons aged >54 years were associated with a higher prevalence of correctable NVI in Nepal and India. Although near vision spectacles were provided free at baseline, wear among those who could benefit was <40% at all but 2 centers (Guangzhou and Los Angeles).
  
  
  CONCLUSIONS
  Prevalence of correctable NVI is greatest among persons of working age, and rates of correction are low in many settings, suggesting that strategies targeting the workplace may be needed.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China. Electronic address: mingguang_he@yahoo.com.
authors.forename: Mingguang
authors.initials: M
authors.lastname: He
authors.affiliation: Programme National de Lutte Contre la Cecite Ministere de la Sante Publique, Niamey, Niger.
authors.forename: Amza
authors.initials: A
authors.lastname: Abdou
authors.affiliation: National Eye Institute, Bethesda, Maryland.
authors.forename: Leon B
authors.initials: LB
authors.lastname: Ellwein
authors.affiliation: Brien Holden Vision Institute and AVRI, University of KwaZulu-Natal, Durban, South Africa.
authors.forename: Kovin S
authors.initials: KS
authors.lastname: Naidoo
authors.affiliation: Nepal Netra Jyoti Sangh, Tripureshwor, Kathmandu, Nepal.
authors.forename: Yuddha D
authors.initials: YD
authors.lastname: Sapkota
authors.affiliation: Lions Aravind Institute of Community Ophthalmology, Aravind Eye Care System, Madurai, India.
authors.forename: R D
authors.initials: RD
authors.lastname: Thulasiraj
authors.affiliation: Doheny Eye Institute, University of Southern California, Los Angeles, California.
authors.forename: Rohit
authors.initials: R
authors.lastname: Varma
authors.affiliation: Chinese Academy of Medical Sciences and Peking Union Medical College Hospital, Beijing, China.
authors.forename: Jialiang
authors.initials: J
authors.lastname: Zhao
authors.affiliation: World Health Organization, Geneva, Switzerland.
authors.forename: Ivo
authors.initials: I
authors.lastname: Kocur
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China; ORBIS International, New York, New York.
authors.forename: Nathan G
authors.initials: NG
authors.lastname: Congdon
mesh_terms: D000328:Adult; D000349:Africa / Q000453:epidemiology; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001208:Asia / Q000453:epidemiology; D015331:Cohort Studies; D004522:Educational Status; D005139:Eyeglasses / Q000706:statistics & numerical data*; D005260:Female; D006301:Health Services Needs and Demand / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012030:Refractive Errors / Q000208:ethnology* / Q000628:therapy*; D012424:Rural Population / Q000706:statistics & numerical data; D017678:Sex Distribution; D014481:United States / Q000453:epidemiology; D014505:Urban Population / Q000706:statistics & numerical data; D015348:Vision, Binocular / Q000502:physiology; D014792:Visual Acuity; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*