Eye-Tracking Beyond Peripersonal Space in Virtual Reality : Validation and Best Practices

Recent developments in commercial virtual reality (VR) hardware with embedded eye-tracking create tremendous opportunities for human subjects researchers. Accessible eye-tracking in VR opens new opportunities for highly controlled experimental setups in which participants can engage novel 3D digital environments. However, because VR embedded eye-tracking differs from the majority of historical eye-tracking research, in both providing for relatively unconstrained movement and stimulus presentation distances, there is a need for greater discussion around methods for implementation and validation of VR based eye-tracking tools. The aim of this paper is to provide a practical introduction to the challenges of, and methods for, 3D gaze-tracking in VR with a focus on best practices for results validation and reporting. Specifically, first, we identify and define challenges and methods for collecting and analyzing 3D eye-tracking data in VR. Then, we introduce a validation pilot study with a focus on factors related to 3D gaze tracking. The pilot study provides both a reference data point for a common commercial hardware/software platform (HTC Vive Pro Eye) and illustrates the proposed methods. One outcome of this study was the observation that accuracy and precision of collected data may depend on stimulus distance, which has consequences for studies where stimuli is presented on varying distances. We also conclude that vergence is a potentially problematic basis for estimating gaze depth in VR and should be used with caution as the field move towards a more established method for 3D eye-tracking.CC BY 4.0Correspondence: Maurice Lamb Maurice.Lamb@his.sepublished: 08 April 2022The raw data supporting the conclusions of this article will bemade available by the authors, without undue reservation. The software used for data collection in this project can be found at https://doi.org/10.5281/zenodo.6368107.Funding of this project was provided through the Knowledge Foundation as a part of both the Recruitment and Strategic Knowledge Reinforcement initiative and within the Synergy Virtual Ergonomics (SVE) project (#20180167).We want to thank the Knowledge Foundation and the associated INFINIT research environment at the University of Skövde for support through funding of both the Recruitment and Strategic Knowledge Reinforcement initiative and within the Synergy Virtual Ergonomics (SVE) project. This support is gratefully acknowledged.