Vergence-accommodation conflict increases time to focus in augmented reality

Vergence-accommodation conflicts (VAC) occur in near-eye displays when the binocular disparity of the 3D rendered content (vergence) does not match the display focal distance (accommodation). VAC has been shown to reduce perceptual image quality, cognitive performance, and oculomotor coordination. In this study, we aimed to investigate the impact of VAC on visual performance in augmented reality (AR). Specifically, we quantified the impact of AR VAC on the ‘Time to Focus’ (TTF); when the user switches focus between real-world content and world-locked AR-rendered content. Our results show that TTF increases exponentially with VAC. The increase is more pronounced at closer vergence distances in displays with a focal distance of 1 D or longer. Finally, we showed that VAC may have a differential effect across age groups; specifically, older users may be affected more in closer focal and longer vergence distances.