title: Prevalence of blindness in Western Australia: a population study using capture and recapture techniques.
abstract: OBJECTIVE
  To determine the prevalence of blinding eye disease in Western Australia using a capture and recapture methodology.
  
  
  METHODS
  Three independent lists of residents of Western Australia who were also legally blind were collated during the capture periods in 2008-9. The first list was obtained from the state-wide blind register. A second list comprised patients routinely attending hospital outpatient eye clinics over a 6-month period in 2008. The third list was patients attending ophthalmologists' routine clinical appointments over a 6-week period in 2009. Lists were compared to identify those individuals who were captured on each list and those who were recaptured by subsequent lists. Log-linear models were used to calculate the best fit and estimate the prevalence of blindness in the Western Australian population and extrapolated to a national prevalence of blindness in Australia.
  
  
  RESULTS
  1771 legally blind people were identified on three separate lists. The best estimate of the prevalence of blindness in Western Australia was 3384 (95% CI 2947 to 3983) or 0.15% of the population of 2.25 million. Extrapolating to the national population (21.87 million) gave a prevalence of legal blindness of approximately 32,892 or 0.15%.
  
  
  CONCLUSIONS
  Capture-recapture techniques can be used to determine the prevalence of blindness in whole populations. The calculated prevalence of blindness suggested that up to 30% of legally blind people may not be receiving available financial support and up to 60% were not accessing rehabilitation services.
authors.affiliation: Centre for Population Health Research, Curtin Health Innovation Research Institute, Curtin University, GPO Box U1987, Perth, Western Australia, Australia. j.crewe@curtin.edu.au
authors.forename: Julie
authors.initials: J
authors.lastname: Crewe
authors.forename: William H
authors.initials: WH
authors.lastname: Morgan
authors.forename: Nigel
authors.initials: N
authors.lastname: Morlet
authors.forename: Antony
authors.initials: A
authors.lastname: Clark
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Lam
authors.forename: Richard
authors.initials: R
authors.lastname: Parsons
authors.forename: Aqif
authors.initials: A
authors.lastname: Mukhtar
authors.forename: Jonathon
authors.initials: J
authors.lastname: Ng
authors.forename: Margaret
authors.initials: M
authors.lastname: Crowley
authors.forename: James
authors.initials: J
authors.lastname: Semmens
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001766:Blindness / Q000175:diagnosis / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009313:National Health Programs / Q000706:statistics & numerical data*; D011159:Population Surveillance / Q000379:methods*; D015995:Prevalence; D012042:Registries; D012189:Retrospective Studies; D014904:Western Australia / Q000453:epidemiology; D055815:Young Adult