title: Global estimates of visual impairment: 2010.
abstract: OBJECTIVE
  From the most recent data the magnitude of visual impairment and its causes in 2010 have been estimated, globally and by WHO region. The definitions of visual impairment are the current definitions of presenting vision in the International Classification of Diseases version 10.
  
  
  METHODS
  A systematic review was conducted of published and unpublished surveys from 2000 to the present. For countries without data on visual impairment, estimates were based on newly developed imputation methods that took into account country economic status as proxy.
  
  
  RESULTS
  Surveys from 39 countries satisfied the inclusion criteria for this study. Globally, the number of people of all ages visually impaired is estimated to be 285 million, of whom 39 million are blind, with uncertainties of 10-20%. People 50 years and older represent 65% and 82% of visually impaired and blind, respectively. The major causes of visual impairment are uncorrected refractive errors (43%) followed by cataract (33%); the first cause of blindness is cataract (51%).
  
  
  CONCLUSIONS
  This study indicates that visual impairment in 2010 is a major health issue that is unequally distributed among the WHO regions; the preventable causes are as high as 80% of the total global burden.
authors: World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland; pascolinid@who.int
authors: Donatella
authors: D
authors: Pascolini
authors: Silvio Paolo
authors: SP
authors: Mariotti
mesh_terms: D001766:Blindness / Q000453:epidemiology* / Q000209:etiology; D014943:Global Health; D006801:Humans; D015354:Vision, Low / Q000453:epidemiology* / Q000209:etiology; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*