The Bifixation Field as a Function of Viewing Distance
Figure 7
Illustration of the observers’ task in Experiment 2. A typical ascending trial: after free-fusing the stimulus, observers moved it out along one of twelve radii until the Nonius lines were perceived as misaligned. Initial eye posture is shown in (a). Perception as the eyes reach the limit of the bifixation field is shown in (b). The black Nonius line was visible to the right eye; the grey Nonius line was visible to the left eye. Dashed circle represents an isovergence circle for reference.
