Inconsistency between the binocular and focus cues in stereoscopic augmented reality overburdens the visual system leading to its stress. However, a high individual variability of tolerance for visual stress makes it difficult to predict and generalize the user gain associated with the implementation of alternative visualization technologies. In this study, we investigated the relationship between the binocular function and perceptual judgments in augmented reality. We assessed the task completion time and accuracy of perceptual distance matching depending on the consistency of binocular and focus cues in the stereoscopic environment of augmented reality. The head-mounted display was driven in two modes: multifocal and monofocal mode, providing consistent-cues and inconsistent-cues condition, respectively. Participants matched the distance of a real object with images displayed at three viewing distances (concordant with distances of display focal planes in the consistent-cues condition). A thorough vision screening was performed before the experiment. As a result, individuals with low convergent fusional reserves and receded near point of convergence misjudged distances to a higher extent in comparison to others in the inconsistent-cues condition. In contrast, perceptual judgments were fast and less overestimated, as well as no significant effect of binocular function was revealed in the consistent-cues condition. We suggest that the binocular function measures characterizing individual tolerance for visual stress might be used as the predictors of user gain in the comparative assessment of new visualization technologies for the augmentation of reality.
The visual search abilities of radiologists are systematically trained due to the specifics of their professional tasks. We investigated whether the visual-motor performance of radiologists, residents and students varied when searching non-medical targets on the volumetric display. As a result, no significant differences were found in the correct response rate among three groups. However, the total number of interactions was considerably higher for the resident radiologists and medical students comparing to the experienced radiologists. Our results suggest that the radiological experience does not interfere with the outcome in the developed visual search task, but may be reflected in motor behavior.