Kinematics of direct reaching in head-mounted and stereoscopic widescreen virtual environments

This research investigated the effects of virtual displays on kinematic parameters during direct pointing at a virtual target. Two virtual displays, three egocentric distances, and three indices of difficulty (IDs) were the independent variables considered in the study. Twelve participants (M = 29.8 ± 3.45 years of age) with normal visual acuity performed a pointing movement in the two VR displays, a stereoscopic widescreen display (SWD) and a head-mounted display (HMD). The movement data were compiled using a motion system. The outcomes revealed that peak velocity and reaction time differed significantly between the SWD and HMD conditions; peak velocity was higher and reaction time was shorter with the SWD than with the HMD. Nonetheless, the effective movement time and confirmation time were not significantly different between the two VR displays. In addition, the distance judgment accuracies of the HMD and SWD were 96% and 86%, respectively; distance was underestimated in the HMD and overestimated in the SWD. Moreover, both peak velocity and reaction time were significantly lower at high ID than at low and medium IDs. The results suggested that using an SWD could be more effective and efficient than an HMD for restoring motor function in upper and lower limbs. On the other hand, an HMD might be appropriate for applications which require exocentric distance judgment precision, such as architecture or medical visualization. Moreover, such findings provide valuable information for developers and designers of human interfaces and applications in virtual reality.