This study compares results of sighting, control, suppression and wink tests of visual dominance with a dissociation test administered to 240 high-achieving (ninetieth percentile and above academically) and low-achieving (twenty-fifth percentile and below academically) students at grades four, eight, and twelve. The study examines differences between visual dissociation and other visual-dominance tests. In so doing, the study tests the proportion of consistent dominance revealed by each test among underachievers with a high incidence of dominance variations, examines possible influences on choice of dominant eye, and compares distributions of dominance functions in high- and low-achieving populations.