Effects of foveal retinal slip on visually induced motion sickness: a pilot study

Abstract

This experiment isolated and studied the effects of eye motions on visually induced motion sickness (VIMS) from the effects of foveal retinal slip velocity on VIMS. Eye motion has been shown to contribute to motion sickness. However, most previous work manipulated eye motion using eye fixation pointer. In so doing eye motion suppression was co-founded with increase in the relative velocity between the eyes and the visual stimulus (retinal slip velocity). Retinal slip is a necessary condition in perception of visual motion and could affect VIMS. However, due to difficulties in controlling eye motion in isolation of retinal slip, few work examined this topic. Guo et al. (2011) studied the effect of eye motion by controlling retinal slip velocity and showed that eye motion can still have significant effects on VIMS after retinal slip velocity is controlled. In this study, four conditions represent the factorial combinations of high (+) and low (-) levels of eye motions (EM) and foveal retinal slip velocity (FRSV). Peripheral retinal slip velocity was kept the same throughout the four conditions. A real time eye-slaved pointer was used to achieve the design and presentation of the conditions. Eight subjects participated in the experiment and within subject design was used. Results of Wilcoxon signed rank tests on preliminary data indicated that reduction of foveal retinal slip while keeping eye movements and peripheral retinal slip the same can significantly reduce levels of VIMS (post-exposure total simulator sickness questionnaire scores: p < 0.02 and 7-point nausea ratings: p < 0.05). Implications of these preliminary results are discussed in the paper.