The athlete is positioned 10 feet (3 meters) from a screen on which the slide is projected. The room is darkened and the athlete wears polarizing glasses, which separate the images seen by the two eyes.
The slide projects 4 rows of 5 circles. On each row, one circle is projected with crossed disparities ranging from 240 to 60 arc seconds. This causes the image of the circle to appear closer to the athlete when viewed through the polarizing lenses. Each row is presented separately, and the athlete is asked to identify the circle that stands out. The time required to respond for each row and minimum disparity that produces the stereo effect are recorded.