Abstract

To search rapidly for information in a scene, it is critical to make quick, accurate saccadic eye movements. Often, while making these movements, a body or head movement is required. Thus, vestibular and saccadic eye movements must be coordinated. It is known that the vestibular system can change with age; e.g., the gain of the system can decrease with age, particularly at low frequencies. However, the effects on saccadic eye movements are not understood. Using a pseudorandom vestibular stimulus (rotation about the vertical) with frequencies from 0.02 to 1.67 Hz, we have measured (a) the gain and phase of the vestibulo-ocular reflex and (b) saccade parameters. Saccade targets were three red LEDs, positioned in the center and 9° to either side. We recruited five observers, 62–69 years, who had been normal on a battery of vestibular tests 2 years prior. There was a slight loss of low frequency relative to high frequency gain, but this trend was not significant. However, the average number of saccade errors doubled while rotating vs remaining stationary. Most errors during rotation were (a) single or multistep saccades of less than half-amplitude or (b) slow eye movements.

© 1986 Optical Society of America