Investigating A Geometrical Solution to the Vergence-Accommodation Conflict for Targeted Movements in Virtual Reality

While virtual reality (VR) holds significant potential to revolutionize digital user interaction, how visual information is presented through VR head-mounted displays (HMDs) differs from naturalistic viewing and interactions in physical environments, leading to performance decrements. One critical challenge in VR development is the vergence-accommodation conflict (VAC), which arises due to the intrinsic constraints of approximating the 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 by manufacturers. This paper presents and evaluates a software solution grounded in a vision-based geometrical model of VAC that mediates 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.