An abnormality of eye movement characterized by impaired smooth-pursuit eye movements.
Comment:
Tracking eye movements consist of two different components, namely, smooth pursuit and saccades. Smooth pursuit, or just pursuit, is a class of rather slow eye movements that minimizes retinal target motion. Saccades are rapid eye movements that align the fovea with the target. Slow-pursuit eye movements are involved in tracking a slowly moving target after the saccadic system has placed the image of the target on the fovea.