title: A nationwide population-based study of low vision and blindness in South Korea.
abstract: OBJECTIVE
  To investigate the prevalence and associated risk factors of low vision and blindness in the Korean population.
  
  
  METHODS
  This cross-sectional, population-based study examined the ophthalmologic data of 22,135 Koreans aged ≥5 years from the fifth Korea National Health and Nutrition Examination Survey (KNHANES V, 2010-2012). According to the World Health Organization criteria, blindness was defined as visual acuity (VA) less than 20/400 in the better-seeing eye, and low vision as VA of 20/60 or worse but 20/400 or better in the better-seeing eye. The prevalence rates were calculated from either presenting VA (PVA) or best-corrected VA (BCVA). Multivariate regression analysis was conducted for adults aged ≥20 years.
  
  
  RESULTS
  The overall prevalence rates of PVA-defined low vision and blindness were 4.98% and 0.26%, respectively, and those of BCVA-defined low vision and blindness were 0.46% and 0.05%, respectively. Prevalence increased rapidly above the age of 70 years. For subjects aged ≥70 years, the population-weighted prevalence rates of low vision, based on PVA and BCVA, were 12.85% and 3.87%, respectively, and the corresponding rates of blindness were 0.49% and 0.42%, respectively. The presenting vision problems were significantly associated with age (younger adults or elderly subjects), female sex, low educational level, and lowest household income, whereas the best-corrected vision problems were associated with age ≥ 70 years, a low educational level, and rural residence.
  
  
  CONCLUSIONS
  This population-based study provides useful information for planning optimal public eye health care services in South Korea.
authors.affiliation: Department of Ophthalmology & Visual Science, College of Medicine, The Catholic University of Korea, Seoul St. Mary's Hospital, Seoul, Korea.
authors.forename: Shin Hae
authors.initials: SH
authors.lastname: Park
authors.affiliation: Clinical Research Center, Asan Medical Center, Seoul, Korea.
authors.forename: Ji Sung
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Department of Ophthalmology, Chonnam National University Medical School and Hospital, Gwangju, Korea.
authors.forename: Hwan
authors.initials: H
authors.lastname: Heo
authors.affiliation: Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Young-Woo
authors.initials: YW
authors.lastname: Suh
authors.affiliation: Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology, School of Medicine, Ewha Womans University, Mok-dong Hospital, Seoul, Korea.
authors.forename: Key Hwan
authors.initials: KH
authors.lastname: Lim
authors.affiliation: Department of Ophthalmology, College of Medicine, Chung-Ang University Hospital, Seoul, Korea.
authors.forename: Nam Ju
authors.initials: NJ
authors.lastname: Moon
authors.affiliation: Department of Ophthalmology, Soonchunhyang University Seoul Hospital, Seoul, Korea.
authors.forename: Sung Jin
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Department of Ophthalmology, Soonchunhyang University Seoul Hospital, Seoul, Korea.
authors.forename: Song Hee
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Ophthalmology, Kim's Eye Hospital, Konyang University College of Medicine, Seoul, Korea.
authors.forename: Seung-Hee
authors.initials: SH
authors.lastname: Baek
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D001766:Blindness / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods*; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D017678:Sex Distribution; D015354:Vision, Low / Q000453:epidemiology*; D014792:Visual Acuity; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*; D055815:Young Adult
keywords: South Korea; blindness; low vision; visual impairment