Examination of smooth pursuit eye movement is useful for detecting cen
tral nervous system disorders. It is important to take patient's age i
nto consideration when evaluating smooth pursuit eye movement. The pur
pose of the present study was to clarify the effect of aging on smooth
pursuit eye movement. Thirty healthy volunteers (three groups of 10 v
olunteers, in their fifties, sixties, and seventies and over, respecti
vely) served as subjects, and 10 healthy young volunteers (23 to 33 ye
ars old: mean age 26) served as controls. The pursuit target was drive
n by sinusoidal waveform with various amplitudes and frequencies. Targ
et peak velocities ranged from 12.6 to 94.2 degrees/s. Eye movement si
gnals were recorded d.c. EOG and pursuit gain (ratio of eye peak veloc
ity to target peak velocity) was measured by a computer. Pursuit gain
decreased with increasing target frequency and velocity in all age gro
ups. This tendency was more remarkable in the older groups than in the
young controls; in particular, it was more frequently seen at a frequ
ency of 0.5 Hz. On the other hand, there was no significant relationsh
ip between pursuit gain and the target amplitude. In the group in thei
r seventies and over, pursuit gain was saturated at about 60 degrees/s
.