Abstract
We studied the relative contribution of a fast and slow component in the slow phase velocity of OKN in the elderly. The cylinder was rotated with an equal velocity of 30°/sec, 60°/sec and 90°/sec. In the dark room, illumination was switched on for 30sec and afterwards turned off. Eye movements were analyzed with a microcomputer. Initial rapid rise in slow phase velocity (IR), maximum steady-state slow phase velocity (SS), slow phase velocity in the 1st OKAN (SR) and the time constant of decay of slow phase velocity of OKAN (TC) were evaluated. This test was examined on 22 healthy elderly. The results were as follows: The number of subjects with a decrease in IR were a majority in the elderly with decreased SS. All persons indicating the decrease in SR showed the decrease in IR. The means in IR and SS in the elderly were significantly smaller than those in the younger subjects at each cylinder speed. SR and TC were significantly smaller in the elderly only at 90°/sec. We suppose that the influence of aging on a fast component makes a more significant contribution to the decrease of slow phase velocity in the elderly.
