Quantifying and characterizing vergence-accommodation-conflict-induced cybersickness in immersive environments

Abstract A significant challenge to the widespread adoption of virtual reality (VR) and augmented reality (AR) environments is cybersickness, which affects a majority of users. With symptoms such as headache, nausea, and blurred vision, cybersickness disrupts the illusion of presence in a virtual environment. Understanding this phenomenon is imperative to democratizing the accessibility and use of this powerful technology. Different visual stimuli induce cybersickness in distinct ways. The psychophysical differences between cybersicknesses induced by distinct sources are largely unknown. Vergence-accommodation conflict (VAC) is believed to contribute to cybersickness. In this paper, we present a systematic user study that specifically analyzes VAC-induced cybersickness. We initiate VAC in a sample of 40 participants by displaying a dynamic sphere that moves in and out of the Zone of Comfort—the region near the focal plane where VAC is minimal. We present evidence for a real-time quantitative measure of VAC-induced cybersickness based on electroencephalogram data. Our findings provide statistically significant evidence that participants exposed to our VAC-inducing condition exhibit decreased beta and gamma spectral power in component clusters with anterior dipole centroids and reduced theta power in clusters with posterior centroids. We present these as candidate correlates rather than a VAC-specific signature because the eyes-open baseline does not match the VAC scene conditions and residual ocular and muscle contributions cannot be fully excluded. We anticipate that this work will lead to the development of strategies to monitor and mitigate VAC-induced cybersickness in virtual environments to improve user experiences and increase adoption of VR and AR.