Assessment of young amblyopes. Array vs. single picture acuities.

A linear array of intact and "jumbled" symbols suitable for testing young children has been used to evaluate 35 young amblyopes. Acuities with the jumbled array test were poorer than those obtained with single symbols: the discrepancy between the jumbled array and single picture acuities was greater for large acuity deficits than small deficits. The depth of amblyopia, indexed by the interocular difference in acuity, was greater for the jumbled array than single pictures. For the patients who could be tested with lines of Snellen letters the jumbled array acuities were closer to line letter acuities than single picture or grating acuities. These results suggest that the jumbled array provides a more sensitive test of amblyopia in young children than single symbols or gratings, possibly because the jumbled array presents contour interactions that exploit the crowding phenomenon.