Effects of eye fixation on visually induced motion sickness: Are they caused by changes in retinal slip velocity?

Watching slowly moving wide field-of-view patterns can cause symptoms of visually induced motion sickness (VIMS) in viewers. A within-subject full factorial experiment was designed to test two hypotheses: 1) when watching patterns rotating at 60 degrees per second (dps), eye fixation increases the peripheral retinal slip velocity leading to a reduction in the levels of VIMS; and 2) when watching patterns rotating at 7 dps, eye fixation increases the peripheral retinal slip velocity leading to an increase in the levels of VIMS. The experimental design used two levels of eye fixation (with and without). Nine participants (4 male and 5 female) were exposed to all four conditions with a week's break between each condition. Results indicated that when watching patterns rotating at 60 dps, eye fixation significantly increased the peripheral retinal slip velocity from 35 dps to 60 dps and reduced the levels of mean nausea from 3.6 to 2.7 (p < 0.01). When watching patterns rotating at 7 dps, eye fixation significantly increased the peripheral retinal slip from 2.6 to 7 dps and only slightly increased the levels of mean nausea. The implications of these results are discussed. Copyright 2011 by Human Factors and Ergonomics Society, Inc. All rights reserved