title: Prevalence and Causes of Visual Impairment in a Chinese Adult Population: The Taizhou Eye Study.
abstract: OBJECTIVE
  To study the current prevalence and causes of low vision and blindness in an adult Chinese population.
  
  
  METHODS
  Population-based, cross-sectional study.
  
  
  METHODS
  We used a random cluster sampling method and evaluated 10 234 eligible subjects ≥45 years old (response rate, 78.1%) in the Taizhou Eye Study.
  
  
  METHODS
  Examinations were performed from July 2012 through December 2013. Participants underwent a detailed examination, including uncorrected visual acuity, best-corrected visual acuity (BCVA), intraocular pressure, axial length, slit-lamp, and fundus examinations to evaluate the prevalence and primary causes of visual impairment (VI).
  
  
  METHODS
  We defined low vision and blindness according to the World Health Organization (WHO) criteria (low vision: BCVA, <20/63-≥20/400; blindness: BCVA, <20/400 in the better eye) and United States criteria (low vision: BCVA, <20/40-≥20/200; blindness: BCVA, <20/200 in the better eye).
  
  
  RESULTS
  Using the WHO BCVA criteria, the standardized prevalence of bilateral low vision and blindness were 5.1% and 1.0%, respectively. Using the United States BCVA criteria, the standardized prevalence were 12.8% and 1.5%, respectively. Using the WHO criteria, the primary causes of bilateral low vision and blindness were cataract (59.1% and 48.5%, respectively), myopic macular degeneration (17.6% and 17.2%, respectively), and age-related macular degeneration (11.6% and 10.1%, respectively). The primary causes of monocular low vision were cataract (55.6%), age-related macular degeneration (12.6%), and myopic macular degeneration (8.9%), whereas those of monocular blindness were cataract (46.8%), atrophy of eyeball or prosthetic eye (10.2%), and cornea opacity (7.3%). A further analysis revealed that in adults 45-59 years old, myopic macular degeneration (59.6% and 27.2%, respectively) and cataract (13.8% and 23.4%, respectively) were the leading causes of bilateral and monocular VI. In adults ≥60 years old, cataract (66.8% and 61.2%, respectively) and age-related macular degeneration (12.6% and 11.8%, respectively) were the primary causes of bilateral and monocular VI.
  
  
  CONCLUSIONS
  The prevalence of low vision and blindness in Chinese adults remains a severe public health problem. In the Taizhou Eye Study, cataract was the leading cause of low vision and blindness. Myopic macular degeneration and cataract were the primary causes of VI in adults 45-59 years and ≥60 years old, respectively.
authors.affiliation: Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China; Myopia Key Laboratory of the Health Ministry, and Visual Impairment and Reconstruction Key Laboratory of Shanghai, Shanghai, China.
authors.forename: Yating
authors.initials: Y
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai, China; Fudan-Taizhou Institute of Health Sciences, Taizhou, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai, China; Fudan-Taizhou Institute of Health Sciences, Taizhou, China.
authors.forename: Jiucun
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Ophthalmology, Taixing People's Hospital, Taixing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.affiliation: Department of Ophthalmology, Taixing People's Hospital, Taixing, China.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China; Myopia Key Laboratory of the Health Ministry, and Visual Impairment and Reconstruction Key Laboratory of Shanghai, Shanghai, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China; Myopia Key Laboratory of the Health Ministry, and Visual Impairment and Reconstruction Key Laboratory of Shanghai, Shanghai, China. Electronic address: luyieent@126.com.
authors.forename: Yi
authors.initials: Y
authors.lastname: Lu
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000208:ethnology*; D058452:Axial Length, Eye; D001766:Blindness / Q000208:ethnology* / Q000209:etiology; D002386:Cataract / Q000453:epidemiology; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008268:Macular Degeneration / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D017678:Sex Distribution; D015354:Vision, Low / Q000208:ethnology* / Q000209:etiology; D014792:Visual Acuity / Q000502:physiology; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*