Figure 1.

Flow diagram of gold standard determination. A child could be classified gold standard “negative” in several ways: the result was “negative” or “inconclusive” in the orthoptic screening and “negative” in the orthoptic examination: children who had a visual acuity of >0.63 (10/17) in either eye or better and no anomalies in the orthoptic examination were classified gold standard “negative” without further examination; children with “positive” or “inconclusive” or “borderline” results in the orthoptic examination were referred. Children with a “positive” screening were all referred. To be classified gold standard “positive,” a child had to be referred and had to have target conditions upon ophthalmological examination.