Impact of Immersive Virtual Reality on the Binocular and Accommodative Function: A Systematic Review About Literature and Its Current Limitations

The use of virtual reality (VR) is expected to increase exponentially in next years, and it is important to study whether VR can generate oculomotor, accommodative and binocular alterations in future users. Visual symptoms after the immersion inside VR have been widely reported, specifically in the case of simulator sickness, but the causes are still in study. Some authors have reported changes on accommodative and binocular parameters, but differences between studies made conclusions difficult.Purpose: The aim of this study is to analyze the scientific literature about the effect of VR on the accommodative and binocular function of healthy subjects with both normal visual conditions and binocular anomalies assessing the quality of the existing studies to detect possible limitations and improve future study designs.Methods: A search was performed in PubMed, Web of Science and Scopus databases with the search equation (Virtual reality OR head-mounted displays) AND (accommodation OR accommodative) AND (vergence* OR convergence OR divergence OR binocular vision). A limitation was made in terms of the date of publication from 2010 onwards, identifying a total of 198 publications. Finally, 15 publications were included in the quality analysis. After a comprehensive analysis of the publications, a quality assessment was performed using a Quality Appraisal Checklist.Results: Research on effects of immersive VR on accommodative and binocular function to this date was focused on quasi-experimental pre-post studies well written and with results supporting their conclusions. Unfortunately, this scientific evidence provides heterogeneous outcomes, being the results in some cases even contradictory.Conclusions: Information about the devices, its interpupillary distance adjustment, the software characteristics and type of task performed by users should be better controlled in future studies. Additionally, participants accommodative and binocular baseline characteristics should be better analyzed to obtain firm conclusions about the consequences of the proper immersive VR experience on visual function.