[The accuracy of saccadic eye movements is associated with their horizontal and vertical direction]

Electro-oculagraphic, photo-oculographic, and magnetoelectro-oculographic methods were used to study and to compare the accuracy of 10 degrees saccadic movements of the eyes in dependence on their direction to the right, to the left, upwards and downwards. Leftward saccades in right-handers and rightward saccades in left-handers proved to be more accurate compared to saccades in the opposite direction. This finding may be related to the functional asymmetry of the cerebral hemispheres. Downward saccades are inaccurate in comparison to upward saccades. Their inaccuracy is caused by overshooting the target. In the case of vertical saccades, the existence of different generators in the brain for triggering upward and downward saccades may play a role, along with a potential preprogramming of the change in the downward look into a sequence of two saccades. The obtained results emphasize the requirement of calibrating the electro-oculogram by saccades in that direction in which the analyzed eye movements are recorded.