Low-contrast visual acuity test for pediatric use.
Single-letter flash cards were made at contrast values of 96%, 7% and 4% to compare high-, intermediate- and low-contrast visual performance in amblyopic children young enough to benefit from occlusion therapy. The single-letter format was intended to differentiate the effect of contrast on reading performance from any effects of nearby contours. Two groups of patients were tested: 37 children aged 3 to 8 years who had completed occlusion therapy and 15 children aged 4 to 8 years who were still receiving occlusion therapy. Their results were compared with the results of 45 control subjects aged 3 to 8 years. Three patterns of visual loss were identified in the patients: predominantly for high-contrast acuity, fairly uniform at high-, intermediate- and low-contrast levels, and, in two patients, loss at low- and intermediate-contrast levels with relative sparing at the high-contrast level. The incidence of high-contrast acuity loss was not significantly different between the two groups, but the proportion of children with no acuity loss at any contrast level was 54% in the group that had completed treatment, compared with 17% of those who were still receiving treatment.
Regan
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Department of Ophthalmology, University of Toronto, Ont.
D000550:Amblyopia / Q000503:physiopathology* / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D009779:Occlusive Dressings; D014787:Vision Tests; D014792:Visual Acuity