Field trial of the Otago photoscreener.

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.