title: Refractive Errors in Koreans: The Korea National Health and Nutrition Examination Survey 2008-2012.
abstract: OBJECTIVE
  Our study provides epidemiologic data on the prevalence of refractive errors in all age group ≥5 years in Korea.
  
  
  METHODS
  In 2008 to 2012, a total of 33,355 participants aged ≥5 years underwent ophthalmologic examinations. Using the right eye, myopia was defined as a spherical equivalent (SE) less than -0.5 or -1.0 diopters (D) in subjects aged 19 years and older or as an SE less than -0.75 or -1.25 D in subjects aged 5 to 18 years according to non-cycloplegic refraction. Other refractive errors were defined as follows: high myopia as an SE less than -6.0 D; hyperopia as an SE larger than +0.5 D; and astigmatism as a cylindrical error less than -1.0 D. The prevalence and risk factors of myopia were evaluated.
  
  
  RESULTS
  Prevalence rates with a 95% confidence interval were determined for myopia (SE <-0.5 D, 51.9% [51.2 to 52.7]; SE <-1.0 D, 39.6% [38.8 to 40.3]), high myopia (5.0% [4.7 to 5.3]), hyperopia (13.4% [12.9 to 13.9]), and astigmatism (31.2% [30.5 to 32.0]). The prevalence of myopia demonstrated a nonlinear distribution with the highest peak between the ages of 19 and 29 years. The prevalence of hyperopia decreased with age in subjects aged 39 years or younger and then increased with age in subjects aged 40 years or older. The prevalence of astigmatism gradually increased with age. Education was associated with all refractive errors; myopia was more prevalent and hyperopia and astigmatism were less prevalent in the highly educated groups.
  
  
  CONCLUSIONS
  In young generations, the prevalence of myopia in Korea was much higher compared to the white or black populations in Western countries and is consistent with the high prevalence found in most other Asian countries. The overall prevalence of hyperopia was much lower compared to that of the white Western population. Age and education level were significant predictive factors associated with all kinds of refractive errors.
authors.affiliation: The Institute of Vision Research, Department of Ophthalmology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Tyler Hyungtaek
authors.initials: TH
authors.lastname: Rim
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, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: Key Hwan
authors.initials: KH
authors.lastname: Lim
authors.affiliation: The Institute of Vision Research, Department of Ophthalmology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Moonjung
authors.initials: M
authors.lastname: Choi
authors.affiliation: Department of Ophthalmology, National Health Insurance Service Ilsan Hospital, Goyang, Korea.
authors.forename: Hye Young
authors.initials: HY
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology, Kim's Eye Hospital, Myung-Gok Eye Research Institute, 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; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D015995:Prevalence; D012030:Refractive Errors / Q000453:epidemiology* / Q000503:physiopathology; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult
keywords: Astigmatism; Hyperopia; Myopia; Refractive errors