title: The prevalence of visual impairment in older adults in mainland China: a systematic review and meta-analysis.
abstract: OBJECTIVE
  This paper presents estimates of the prevalence of blindness and low vision among older adults over 50 years of age in mainland China.
  
  
  METHODS
  All primary reports of population-based studies that reported the prevalence or incidence of visual impairment among older populations in mainland China were identified. Twenty-four population-based studies were included in this systematic review. Blindness is defined as visual acuity of less than 3/60, or a corresponding visual-field loss to less than 10 degrees in the better eye with the best possible correction; low vision is defined as visual acuity of less than 6/18, but equal to or better than 3/60 in the better eye with the best possible correction. The pooled prevalence estimates of blindness and low vision were calculated assuming a random-effects model. Relative odds with 95% confidence intervals (95% CIs) were calculated, stratified by methodological and socioeconomic variables.
  
  
  RESULTS
  The overall pooled prevalence of blindness was 1.7% (95% CI 1.4-2.1). The results of the meta-regression showed the significance of a predictor variable: geographic region. The blindness rates per 100 older adults in various regions were 1.4 (0.9-2.0) in East China, and 1.4 (1.0-2.0) in Central China and 2.5 (1.9-3.2) in Western China. The overall pooled prevalence of low vision was 4.1% (3.4-5.1) and the independent pooled prevalence rates stratified by geographic region were 3.6% (2.6-5.1) in East China, 3.6% (2.4-5.2) in Central China and 5.2% (3.6-7.4) in Western China.
  
  
  CONCLUSIONS
  Blindness or low vision affects approximately 5.8% Chinese adults older than 50 years. The prevalence of visual impairment, and especially blindness, vary greatly by the developmental status of geographic region.
authors.affiliation: Department of Ophthalmology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Jin-Wei
authors.initials: JW
authors.lastname: Cheng
authors.forename: Shi-Wei
authors.initials: SW
authors.lastname: Cheng
authors.forename: Ji-Ping
authors.initials: JP
authors.lastname: Cai
authors.forename: You
authors.initials: Y
authors.lastname: Li
authors.forename: Rui-Li
authors.initials: RL
authors.lastname: Wei
mesh_terms: D000368:Aged; D001766:Blindness / Q000453:epidemiology*; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015354:Vision, Low / Q000453:epidemiology*