The effect of age on dynamic visual performance was investigated in a sample of 1850 healthy male and female subjects between the ages of 4 and 80 years with the use of a form-from-motion analogue to the Landolt ring (Wist et al, 1996 Pflügers Archiv 431 O23). Within a random-dot display, Landolt rings of the same average luminance as their surrounds become visible only when the dots within the ring are moved briefly while those of the surround remain stationary. Thus detection of gap location is based upon motion contrast (form-from-motion) rather than luminance contrast. With the size and exposure duration of the centrally presented ring held constant, motion contrast is manipulated by varying the percentage of moving dots within the ring (100%, 50%, 30%, and 20%). Subjects reported gap location (top, bottom, left, or right) either verbally, by button press, or moving a joystick. An expected percent correct responses decreased from an average of 90% at 100% motion contrast to 65% at 20% motion contrast. A developmental trend was clear for the age variable with performance improving at all motion contrast levels from the age of 4 to 20 years followed by a plateau and a clear decline after the age of 50 years. Intersubject variability increased appreciably beyond this age, consistent with the hypothesis of a differential decline of dynamic vision with age. Applications of this test to date include the testing of glaucoma patients and truck drivers.
