Pseudo-false positive eye/vision photoscreening due to accommodative insufficiency. A serendipitous benefit for poor readers?

Abstract

Background: Children whose eyes and vision are otherwise normal and who should screen negatively as normals, but who fail to compensate for their normal mild hyperopia (i.e. by normally accommodating, or rather actually failing to accommodate) will generate hyperopic crescents in a photoscreen test that can be interpreted as "positive" (for pathology) because high and asymmetric levels of hyperopia are common risk factors for amblyopia. This would therefore usually be considered a "false positive" and no further care would be offered. However, this failure to compensate, may in fact be a pathological disorder, accommodative insufficiency, making this apparently "false positive" situation actually a actually a "false-positive-false- negative positive test", or more simply a "false- false positive test".

Methods: The Alaska Blind Child Discovery Project photoscreened just under 16,000 children referring 6% as "positive", of which, after examination, the false positive rate was just 6% of those referred (0.4% of the total number screened).

Results: Ten (42%) of the 24 false positives had evidence of accommodative insufficiency inspite of only average (for age) amounts of cycloplegic hyperopia and a lag of accommodation on dynamic retinoscopy. Eight of the 10 were boys of kindergarten age. Most of these subsequently benefitted from prescription and use of reading glasses of low plus sphere correction.

Conclusion: About 0.15% of photoscreened children, or 2.5% of those screening positive, and 42% (10/24) found initially on exam to be falsely positive, yielding hyperopic interpretations despite low and usually acceptably normal for age amounts of hyperopia, are in fact suffering from a pathological accommodative insufficiency. Identification of such false- false positives by a combination of photoscreening and dynamic retinoscopy may be used to determine which students might be helped with enforced reading glasses. Confirmatory exams on photoscreen positive-hyperopia cases should include an assessment of accommodation to identify these children.