Stereo thresholds on the Frisby test for different groups.

“N tested” refers to the number of participants who were examined and who demonstrated an ability to understand the test and cooperate with the tester. “N stereonegative” refers to the number who could not perform the test at the largest disparity available, despite a demonstrated ability to understand the test and cooperate. Note: the number of males and females does not sum to the total N in the group, since gender was not recorded for all participants. All ages are in years and all stereo thresholds are in seconds of arc. Medians are followed by the interquartile range in parentheses.