Eye movement data of animals are available over a wide variety of stimulus conditions. But, motion sickness due to angular stimulation about an earth horizontal axis may frustrate the measurements, why human studies are limited.

As part of a longitudinal investigation considering vestibular adaptation in aviators, we recorded eye movements evoked by angular velocity steps in yaw, pitch, and roll, about both the earth vertical and earth horizontal axis. This gives a data set of human eye movement parameters over all six basic conditions, though also in this study, not all subjects could withstand all conditions.

The results show that these parameters vary systematically between conditions. The most striking difference reconfirms the presence of only a one dimensional velocity storage mechanism, despite the three-dimensional nature of eye movements. With respect to the primary objective of this study, the data show that vestibular adaptation primarily takes place at the level of this velocity storage. Moreover, desensitisation of motion sickness by repetitive exposure to a provoking stimulus seems to coincide with a reduction of this velocity storage only.

These findings indicate that the susceptibility to motion sickness is determined at a central level, rather than at the peripheral level of the end organs.