title: Assessing the diagnostic validity of a blind register.
abstract: BACKGROUND
  To validate the accuracy of clinical ophthalmic information held on the West Australian blind register.
  
  
  METHODS
  Community-based cross-sectional study.
  
  
  METHODS
  Legally blind or severely vision-impaired people were selected randomly from the Association for the Blind of Western Australia register.
  
  
  METHODS
  Individuals were reviewed by one of two consultant ophthalmologists.
  
  
  METHODS
  The positive predictive value (ppv), sensitivity and specificity for legal blindness status and diagnostic causes of vision loss were calculated using data extracted from the Association for the Blind of Western Australia blind register.
  
  
  RESULTS
  273 blind or near blind people were reviewed from the register total of 4271 individuals. There were more women (57%) than men, median age 81 years. For legal blindness status the ppv was 0.88 (95% confidence interval [CI] 0.82-0.92), sensitivity 0.75 (95% CI 0.74-0.84) and specificity 0.6 (95% CI 0.46-0.73). The ppv for the diagnostic causes of blindness were: age-related macular degeneration = 0.95 (95% CI 0.91-0.97), retinitis pigmentosa ppv = 1 (95% CI 0.81-1.0), diabetic retinopathy ppv = 0.9 (95% CI 0.57-0.99), optic neuropathies ppv = 0.77 (95% CI 0.51-0.92) and glaucoma ppv = 0.87 (95% CI 0.7-0.96). Forty individuals (15%) had treatable conditions contributing to their vision loss.
  
  
  CONCLUSIONS
  The blind register diagnoses and legal blindness status are of high accuracy. This information allows useful linkages to other databases for studies of blindness interactions. A regular updating mechanism would improve the future accuracy of this valuable regional asset. The presence of untreated cataract suggests that regular follow up and appropriate treatment may help optimize vision in blind patients.
authors.affiliation: Centre for Population Health Research, Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia. j.crewe@curtin.edu.au
authors.forename: Julie M
authors.initials: JM
authors.lastname: Crewe
authors.forename: William H
authors.initials: WH
authors.lastname: Morgan
authors.forename: Nigel
authors.initials: N
authors.lastname: Morlet
authors.forename: Katrina
authors.initials: K
authors.lastname: Spilsbury
authors.forename: Aqif
authors.initials: A
authors.lastname: Mukhtar
authors.forename: Antony
authors.initials: A
authors.lastname: Clark
authors.forename: Jonathon Q
authors.initials: JQ
authors.lastname: Ng
authors.forename: Margaret
authors.initials: M
authors.lastname: Crowley
authors.forename: James B
authors.initials: JB
authors.lastname: Semmens
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001766:Blindness / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012042:Registries / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017678:Sex Distribution; D015354:Vision, Low / Q000453:epidemiology*; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*; D014904:Western Australia / Q000453:epidemiology; D055815:Young Adult