28-1:Invited Paper: Why Focus Cues Matter

Abstract

Stereoscopic displays present different images to the two eyes and thereby create a compelling 3D sensation. However, such displays cause a host of perceptual and ergonomic problems. These problems occur because some of the presented depth cues (i.e., perspective and binocular disparity) specify the intended 3D scene while focus cues (blur and accommodation) specify the fixed distance of the display itself. These problems are particularly problematic in VR and AR displays. We have developed a stereoscopic display that circumvents these problems. Using the display, we investigated how incorrect focus cues affect visual perception, visual performance, and, most importantly, visual comfort. With respect to perception, we showed that the ability to perceive correct depth ordering is significantly improved when focus cues are correct. With respect to visual performance, we showed that the ability to binocularly fuse stimuli is substantially improved when the vergence-accommodation conflict is minimized. Finally, with respect to visual comfort, we showed that comfort is significantly increased when the vergence-accommodation conflict is zero. I offer suggestions on ways to create nearly correct focus cues in practical stereoscopic displays, particularly VR and AR.