1. A fitness impairment tester comprising: pupil imaging optics and focusing an image of the subject's pupil on an image plane; pupil diameter measurement means for measuring diameter of and changes in the image of the subject's pupil on said image plane in response to light stimuli; an eye tracker for tracking movements of the subject's eye in response to moving light stimuli; data acquisition means responsive to said pupil diameter measuring means and said eye tracking means for generating dynamic measures of pupil diameter and movements of the subject's eye as a function of time; a database for storing baseline data for the subject; and a computer controlled by a stored program for controlling said light stimuli and receiving said dynamic measures of pupil diameter and movements, accessing said baseline data for the subject, and providing an output indicative of a deviation of said current measurements from said baseline data.