Background Over the past few years, virtual reality-based visual field assessments have been increasingly investigated. However, due to the limited field of view (FOV) that a virtual reality (VR) headset can offer, research to identify the visual field's outer limits has not been possible as the FOV falls short of the human visual field limits. This limitation has hindered the ability to accurately identify the outer limits of the visual field using VR technology. The Peili Research app, a VR-based kinetic perimeter, addresses this issue by employing off-centred focus points to expand the effective angle that can be tested.
Research Objective This research explores the feasibility of employing the Peili Research app, alongside the Pico Neo 2 Eye VR headset, as a bedside tool for visual field assessment.
Methods A series of analyses were conducted to evaluate the Peili Research app’s performance in visual field testing. The Spearman correlation matrix was used to assess test-retest reliability, and a comparison with Goldmann perimetry was made. The app’s design was evaluated by calculating the increase in effective testable angle through the off-centred focus point. In addition, the impact of observer differences due to human reaction time and the impact of stimulus colour contrast on the results was investigated. Data processing was conducted using a custom-developed MATLAB script to analyse the Peili data and determine the visual field angles in isopters.
Results Visual representations of the Peili Research app suggested a certain extent of test-retest reliability. However, Spearman correlations varied between poor and moderate. The application extends the testable visual field angle by 23 degrees on average. The study revealed that human reaction time in recording visual stimuli on the tablet led to an average underestimation of visual field angles by 5.38 degrees (p<0.001). Furthermore, colour contrast significantly affected detection angles, with green stimuli being detected at larger angles compared to blue and yellow stimuli (p<0.001). Clinical testing on postoperative volunteers highlighted practical challenges.
Conclusion The Peili Research app shows promise as a VR-based tool for visual field assessment, capable of expanding the testable visual field angle. However, variability in results, mainly due to the location of the focus points, reaction time, colour contrast, and the instability of the VR headset, highlights the need for further design refinements. Addressing these issues could enhance the app’s clinical applicability, making it a valuable tool for bedside visual field testing and improving patient outcomes.