Investigating a geometrical solution to the vergence-accommodation conflict for targeted movements in virtual reality

Abstract

Virtual reality (VR) uses head-mounted displays to simulate perceptuomotor experiences in physical environments. However, this mediated approach alters how visual information is presented compared to naturalistic viewing, which can affect user performance. One critical challenge in VR development is the vergence-accommodation conflict (VAC), which stems from the inherent limitations of approximating natural viewing geometry through digital displays. Although various hardware and software solutions have been proposed to address VAC, no commercially viable option has been universally adopted. This paper presents and evaluates a software solution grounded in a vision-based geometrical model of VAC that alleviates VAC's impact on movement in VR. This model predicts the impact of VAC as a constant offset to the vergence angle, distorting the binocular viewing geometry that results in movement undershooting. In Experiment 1, a 3D pointing task validated the model's predictions and demonstrated that VAC primarily affects online movements involving real-time visual feedback. Experiment 2 implemented a shader program to rectify the effect of VAC, improving movement accuracy by approximately 30%. Overall, this work presented a practical approach to reducing the impact of VAC on HMD-based manual interactions, enhancing the user experience in virtual environments.