Field trial of the Otago photoscreener

Can J Ophthalmol. 1995 Jun;30(4):193-7.


Objective: To assess the effectiveness of the Otago photoscreener in detecting amblyogenic factors in the general population.

Design: Prospective clinical trial.

Setting: Suburban school district in Delta, BC.

Participants: A total of 1245 kindergarten children.

Interventions: 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).

Main outcome measures: 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.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amblyopia / diagnosis*
  • British Columbia
  • Child, Preschool
  • Double-Blind Method
  • False Negative Reactions
  • Humans
  • Photography / instrumentation*
  • Predictive Value of Tests
  • Prospective Studies
  • Refractive Errors / diagnosis*
  • Sensitivity and Specificity
  • Strabismus / diagnosis*
  • Vision Disorders
  • Vision Tests / methods*