UNEQUAL AMPLITUDE SACCADES PRODUCED BY ANISEIKONIC PATTERNS - EFFECTSOF VIEWING DISTANCE

This study describes differences in horizontal and vertical disconjuga te saccades under far and close viewing conditions of two dichopticall y presented aniseikonic random checkerboard patterns. At far viewing, disconjugacy of horizontal saccades requiring divergence was accomplis hed intrasaccadically after several minutes; for convergence the intra saccadic disconjugacy was limited. Size differences partially persiste d in open-loop trials, At close viewing intrasaccadic divergent change s in conjugacy were instantaneous, but motor storage during open-loop was absent, It is concluded that disconjugate saccades to targets at f ar distance lead to an adaptation process, whereas at close viewing di stance horizontal disparity is a visual compensation process used dire ctly to scale the relative amplitudes of both eyes, not leading to ada ptation, The time-course of disconjugate vertical saccades was much sl ower, with mostly postsaccadic vergence. Nearby viewing enhanced the d isconjugacy of vertical saccades.