Abstract
Purpose: :
To study saccade-vergence interaction we analyzed the quick phases of the involuntary version-vergence nystagmus induced by motion stimuli in the ground plane.
Methods: :
We displayed backward/forward motion stimuli on a monitor positioned face-up and 10 cm below the eyes. Using a search coil system, we digitized the eye movement.
Results: :
It was found that the involuntary version-vergence nystagmus had both vertical version and horizontal vergence components. Backward motion induced monophasic divergent quick phases and upward versional quick phases; forward motion induced biphasic divergence-convergence quick phases and downward versional quick phases. A time dissociation of about 20 ms between version velocity peak and convergence velocity peak was observed. Linear relationships between vergence peak velocity and versional saccadic peak velocity were demonstrated.
Keywords: eye movements • ocular motor control • vergence