The autokinetic effect (also referred to as autokinesis) is a phenomenon of visual perception in which a stationary, small point of light in an otherwise dark or featureless environment appears to move. It presumably occurs because motion perception is always relative to some reference point. In darkness or in a featureless environment there is no reference point, so the movement of the single point is undefined.
To prevent this illusion, focus the eyes on objects at varying distances and avoid fixating on one target. Be sure to maintain a normal scan pattern.