Investigating Cyclical Stereoscopy Effects Over Visual Discomfort and Fatigue in Virtual Reality While Learning

Purpose: It is hypothesized that cyclical stereoscopy (displaying stereoscopy or 2D cyclically) has effect over visual fatigue, learning curves and quality of experience, and that those effects are different from regular stereoscopy. Materials and Methods: 59 participants played a serious game simulating a job interview with a Samsung Gear VR Head Mounted Display (HMD). Participants were randomly assigned to 3 groups: HMD with regular stereoscopy (S3D) and HMD with cyclical stereoscopy (cycles of 1 or 3 minutes). Participants played the game thrice (third try on a PC one month later). Visual discomfort, Flow, Presence, were measured with questionnaires. Visual Fatigue was assessed pre-and post-exposure with optometric measures. Learning traces were obtained in-game. Results: Visual discomfort and flow are lower with cyclical-S3D than S3D but not Presence. Cyclical stereoscopy every 1 minute is more tiring than stereoscopy. Cyclical stereoscopy every 3 minutes tends to be more tiring than stereoscopy. Cyclical stereoscopy groups improved during Short-Term Learning. None of the statistical tests showed a difference between groups in either Short-Term Learning or Long-Term Learning curves. Conclusion: cyclical stereoscopy displayed cyclically had a positive impact on Visual Comfort and Flow, but not Presence. It affects oculomotor functions in a HMD while learning with a serious game with low disparities and easy visual tasks. Other visual tasks should be tested, and eye-tracking should be considered to assess visual fatigue during exposure. Results in ecological conditions seem to support models suggesting that activating cyclically stereopsis in a HMD is more tiring than maintaining it.