title: Prevalence and causes of visual impairment in an elderly Chinese population in Taiwan: the Shihpai Eye Study.
abstract: OBJECTIVE
  Few population-based data on the prevalence and causes of visual impairment are available from East Asia. The purpose of this study was to determine the prevalence and causes of visual impairment in an elderly Chinese population in Taiwan.
  
  
  METHODS
  Population-based cross-sectional study.
  
  
  METHODS
  The Shihpai Eye Study was a survey of vision and ocular disease among an elderly Chinese population 65 years of age or older residing in Shihpai, Taiwan. A random sample of 2045 elderly residents was identified and selected from the household registration databank. Among them, 1361 (66.6%) underwent a detailed ophthalmic examination.
  
  
  METHODS
  The ophthalmic examination included best-corrected visual acuity measurements using standardized protocols. Visual acuity was assessed with a Snellen E chart. The major cause of visual loss was identified for all participants who were visually impaired.
  
  
  METHODS
  Low vision and blindness were defined as a best-corrected visual acuity in the eye with better vision worse than 20/60 to a lower limit of 20/400 and worse than 20/400, respectively, according to World Health Organization categories of visual impairment.
  
  
  RESULTS
  The mean age of the participants was 72.2 (range, 65-91) years old. A total of 40 participants met the World Health Organization criteria of low vision, and 8 were diagnosed as blind. The rate of blindness and low vision was estimated to be 0.59% (95% confidence interval, 0.25%, 1.16%) and 2.94% (95% confidence interval, 2.11%, 3.99%), respectively. There was a significant increase in the rate of low vision (P<0.001) from 0.83% at 65 to 69 years of age to 8.33% at age 80 years or older. There was no gender difference in the prevalence of blindness or low vision. The leading cause of visual impairment was cataract (41.7%), followed by myopic macular degeneration (12.5%) and age-related macular degeneration (10.4%).
  
  
  CONCLUSIONS
  The rate of blindness and low vision is close to that reported for other developed countries. The high frequency of myopic macular degeneration as a major cause of visual loss, however, is not observed in European-derived populations. Specific prevention or low-vision rehabilitation programs should be developed for the elderly Chinese population.
authors.affiliation: Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan. wmhsu@vghtpe.gov.tw
authors.forename: Wen-Ming
authors.initials: WM
authors.lastname: Hsu
authors.forename: Ching-Yu
authors.initials: CY
authors.lastname: Cheng
authors.forename: Jorn-Hon
authors.initials: JH
authors.lastname: Liu
authors.forename: Su-Ying
authors.initials: SY
authors.lastname: Tsai
authors.forename: Pesus
authors.initials: P
authors.lastname: Chou
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001766:Blindness / Q000208:ethnology* / Q000209:etiology*; D015984:Causality; D002681:China / Q000208:ethnology; D003430:Cross-Sectional Studies; D005128:Eye Diseases / Q000150:complications; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D013624:Taiwan / Q000453:epidemiology; D015354:Vision, Low / Q000208:ethnology* / Q000209:etiology*; D014792:Visual Acuity; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*