The Statistics of Eye Movements and Binocular Disparities during VR Gaming: Implications for Headset Design

The human visual system evolved in environments with statistical regularities. Binocular vision is adapted to these such that depth perception and eye movements are more precise, faster, and performed comfortably in environments consistent with the regularities. We measured the statistics of eye movements and binocular disparities in virtual-reality (VR) - gaming environments and found that they are quite different from those in the natural environment. Fixation distance and direction are more restricted in VR, and fixation distance is farther. The pattern of disparity across the visual field is less regular in VR and does not conform to a prominent property of naturally occurring disparities. From this we predict that double vision is more likely in VR than in the natural environment. We also determined the optimal screen distance to minimize discomfort due to the vergence-accommodation conflict, and the optimal nasal-temporal positioning of head-mounted display (HMD) screens to maximize binocular field of view. Finally, in a user study we investigated how VR content affects comfort and performance. Content that is more consistent with the statistics of the naturalworld yields less discomfort than content that is not. Furthermore, consistent content yields slightly better performance than inconsistent content.

Automated summary

The human visual system has evolved to adapt to environments with statistical regularities. However, when exposed to virtual reality (VR) gaming environments, the statistics of eye movements and binocular disparities are found to be quite different from those in the natural environment. This may result in greater discomfort and increased likelihood of double vision in VR. Additionally, VR content that aligns more closely with the statistics of the natural world leads to less discomfort and slightly better performance compared to inconsistent content.