Visual Tracking

Definition

During visual tracking, the main objective of the observer is to keep the image of the fixated item on the fovea, the area of the retina where visual resolution is best. Normally, the observer tracks moving targets using a combination of smooth pursuit movements and small saccades. Smooth pursuit movements allow the observer to track a moving object, while saccades (derived from the French word for jerk or to pull) allow the observer to quickly redirect their gaze to the object of interest. During smooth pursuit, eye velocities are generated that approximate the velocity of the moving target object. When the eyes and target are in synch, the velocity of the target’s retinal image is reduced to zero. If the eyes fall short of, or overshoot the target, saccades are generated to reposition the image of the target object back on to the region of the fovea. During visual tracking, the vestibulo-ocular reflex and optokinetic movements permit the observer to compensate for head...