title: Field trial of the Otago photoscreener.
abstract: OBJECTIVE
  To assess the effectiveness of the Otago photoscreener in detecting amblyogenic factors in the general population.
  
  
  METHODS
  Prospective clinical trial.
  
  
  METHODS
  Suburban school district in Delta, BC.
  
  
  METHODS
  A total of 1245 kindergarten children.
  
  
  METHODS
  Screening for visual defects was done with the Otago photoscreener (by a technician) and the regular manual method (by a health care aide). A standard ophthalmologic examination was performed by a pediatric ophthalmologist and an orthoptist in a random sample of 20% of all children with normal results of screening (n = 241) plus all those with abnormal results (n = 29).
  
  
  METHODS
  Sensitivity, specificity, positive predictive value, rates of false-negative and false-positive results.
  
  
  RESULTS
  The Otago screener had higher sensitivity than the manual technique (81% vs. 33%), especially for strabismus and cataracts. The specificity values of the two techniques were 98% and 97% respectively, and the positive predictive values were 77% and 54% respectively. The manual technique failed to identify 5.8% of children with visual defects, compared with 1.6% for the Otago screener.
  
  
  CONCLUSIONS
  The Otago photoscreener is a superior instrument for identifying amblyogenic eye disease. However, given the relatively low yield, the value of any screening method should be assessed with regard to both costs and benefits.
authors.affiliation: Department of Ophthalmology, University of British Columbia, Vancouver.
authors.forename: R
authors.initials: R
authors.lastname: Kennedy
authors.forename: S B
authors.initials: SB
authors.lastname: Sheps
authors.forename: D
authors.initials: D
authors.lastname: Bagaric
mesh_terms: D000550:Amblyopia / Q000175:diagnosis*; D001955:British Columbia; D002675:Child, Preschool; D004311:Double-Blind Method; D005188:False Negative Reactions; D006801:Humans; D010781:Photography / Q000295:instrumentation*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012030:Refractive Errors / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D013285:Strabismus / Q000175:diagnosis*; D014786:Vision Disorders; D014787:Vision Tests / Q000379:methods*