FAST DISCONJUGATE ADAPTATIONS OF SACCADES IN MICROSTRABISMIC SUBJECTS

In normal subjects, saccade amplitude inequality can be induced almost immediately when the image is made larger for one eye. This disconjug acy allows binocular fusion at the point of regard despite the image s ize inequality. It persists under subsequent monocular viewing which s uggests a fast adaptive mechanism. This study tests whether such disco njugacy can be induced in subjects with microstrabismus who do not hav e foveal fusion. Three microstrabismic subjects viewed a random dot pa ttern the size of which was 10% larger in one eye. Within 40 sec horiz ontal saccades became larger in the eye viewing the larger image by 4- 10%; the induced disconjugacy persisted under subsequent monocular vie wing. Thus, fast disconjugate adaptation is possible in microstrabismu s demonstrating that foveal fusion is not necessary to achieve it.