J. Edward Swan II

Measuring eye vergence angle in extended reality

Mohammed Safayet Arefin, J. Edward Swan II, Russell Cohen-Hoffing, and Steven M. Thurman. Measuring eye vergence angle in extended reality. PLOS ONE, Oct 2025. in press.

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Abstract

Recently, extended reality (XR) displays, including augmented reality (AR) andvirtual reality (VR), have integrated eye tracking capabilities, which could enable novel ways of interacting with XR content. In natural settings, eye vergence angle (EVA) changes constantly, based on the distance of fixated objects. Here, we measured EVA for eye fixations on real and virtual target objects in three different environments: real objects in the real world (real), virtual objects in the real world (AR), and virtual objects in a virtual world (VR). In a repeated measures design with 13 participants, EVA was measured while participants fixated on targets at varying distances. As expected, the results showed a significant main effect of target depth such that increasing EVA was associated with closer targets. However, there were consistent individual differences in baseline EVA. There was also a smaller but statistically significant main effect of environment (real, AR, VR) on EVA. Importantly, EVA was stable with respect to the starting depth of previously fixated targets and invariant to the direction (convergence vs. divergence) of vergence changes. In addition, EVA proved to be a more veridical depth estimate than verbal subjective depth judgments.

BibTeX

@Article{PLOSOne25-eva, 
  author =      {Mohammed Safayet Arefin and J. Edward {Swan~II} and
                 Russell Cohen-Hoffing and Steven M. Thurman},
  title =       {Measuring eye vergence angle in extended reality},
  journal =     {PLOS ONE},
  month =       {Oct}, 
  year =        2025, 
  note =        {in press.},
abstract =      {
Recently, extended reality (XR) displays, including augmented reality (AR) and
virtual reality (VR), have integrated eye tracking capabilities, which could 
enable novel ways of interacting with XR content. In natural settings, eye 
vergence angle (EVA) changes constantly, based on the distance of fixated 
objects. Here, we measured EVA for eye fixations on real and virtual target 
objects in three different environments: real objects in the real world (real), 
virtual objects in the real world (AR), and virtual objects in a virtual world 
(VR). In a repeated measures design with 13 participants, EVA was measured while 
participants fixated on targets at varying distances. As expected, the results 
showed a significant main effect of target depth such that increasing EVA was 
associated with closer targets. However, there were consistent individual 
differences in baseline EVA. There was also a smaller but statistically 
significant main effect of environment (real, AR, VR) on EVA. Importantly, EVA 
was stable with respect to the starting depth of previously fixated targets and 
invariant to the direction (convergence vs. divergence) of vergence changes. In 
addition, EVA proved to be a more veridical depth estimate than verbal 
subjective depth judgments.}, 
}