title: Secular trends of reduced visual acuity from 1985 to 2010 and disease burden projection for 2020 and 2030 among primary and secondary school students in China.
abstract: OBJECTIVE
  Understanding the burden and trends of reduced visual acuity (VA), a proxy measure for myopia, is essential to guide future health care and clinical management in China.
  
  
  OBJECTIVE
  To describe the secular trends from 1985 to 2010, correlate the prevalence of reduced VA among children and adolescents with population density, and project the burden of reduced VA in China in 2020 and 2030.
  
  
  METHODS
  The National Survey on the Constitution and Health of Chinese Students conducted from 1985 to 2010, including 6 repeated surveys with a 3-stage clustering sampling strategy.
  
  
  METHODS
  Mainland China.
  
  
  METHODS
  Primary and secondary school students 7 to 18 years of age were randomly selected from 30 of 31 mainland provinces, excluding Tibet.
  
  
  METHODS
  Unaided distance VA was measured using a retroilluminated logMAR chart with tumbling-E optotypes. World Population Prospects data (the 2012 revision from the Population Division of the Department of Economic and Social Affairs of the United Nations) were used to project the number of people affected by reduced VA in 2020 and 2030.
  
  
  RESULTS
  This analysis included 725 423, 142 655, 206 601, 219 663, 234 377, and 215 308 students in 1985, 1991, 1995, 2000, 2005, and 2010, respectively. The overall prevalence of reduced VA was 28.6% (95% CI, 28.4%-28.7%) in 1985, 38.6% (95% CI, 38.3%-38.8%) in 1991, 41.0% (95% CI, 40.8%-41.2%) in 1995, 38.5% (95% CI, 38.3%-38.7%) in 2000, 49.5% (95% CI, 49.3%-49.7%) in 2005, and 56.8% (95% CI, 56.6%-57.0%) in 2010. Girls were more susceptible than boys to having reduced VA (odds ratio, 1.38 [95% CI, 1.35-1.40]), and reduced VA was more prevalent in urban areas than in rural areas (odds ratio, 1.84 [95% CI, 1.81-1.87]). Reduced VA was not significantly associated with population density (P = .11). The projected numbers of cases with reduced VA are about 152.4 million (95% CI, 151.9-152.9 million) in 2020, increasing to 180.4 million (95% CI, 179.8-181.2 million) in 2030 among students who are 7 to 18 years of age in mainland China.
  
  
  CONCLUSIONS
  There was an increasing trend of reduced VA in both urban and rural areas from 1985 to 2010 in China. Although reduced unaided distance VA is not equal to visual impairment, these summary data are helpful in designing strategies for eye care and health services in China, which may also have public health implications for other developing countries whose economies are growing rapidly.
authors.affiliation: School of Public Health, Medical College of Soochow University, Suzhou, Jiangsu, China.
authors.forename: Hong-Peng
authors.initials: HP
authors.lastname: Sun
authors.affiliation: School of Public Health, Medical College of Soochow University, Suzhou, Jiangsu, China.
authors.forename: Ang
authors.initials: A
authors.lastname: Li
authors.affiliation: School of Public Health, Medical College of Soochow University, Suzhou, Jiangsu, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Xu
authors.affiliation: School of Public Health, Medical College of Soochow University, Suzhou, Jiangsu, China.
authors.forename: Chen-Wei
authors.initials: CW
authors.lastname: Pan
mesh_terms: D000293:Adolescent; D002648:Child; D002681:China / Q000453:epidemiology; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D009216:Myopia / Q000453:epidemiology*; D011156:Population Density; D015995:Prevalence; D012424:Rural Population / Q000639:trends*; D017678:Sex Distribution; D013334:Students; D014505:Urban Population / Q000639:trends*; D014786:Vision Disorders / Q000453:epidemiology*; D014792:Visual Acuity; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*