ABSTRACT This paper reviews the definition, causation, and significance of fixation disparity and suggests that the magnitude and character of fixation disparity depend on several major parameters: individual differences in the efficiency of motor and sensory processes of binocularity; natural or prism‐induced demands on motor fusion; the presence or absence of foveal or parafoveal fusion clues; and the presence or absence of vergence adaptation. The clinical and research usefulness of fixation disparity as an indicator of binocular stress is emphasized.
Darrell B. Carter (Mon,) studied this question.