VIRTUAL ENVIRONMENT SICKNESS - A TAKE FROM AVIATION MEDICINE PERSPECTIVE

Virtual Environment (VR) helmets are now mainstream, and a variety of uses arose. We focus here on medical and aeronautical use, with the main goal of identifying and possible counteracting the motion sickness phenomena. Methods: A literature review of the main medical problems associated with VR displays, filtered through personal experience with spatial disorientation, NVG, flight simulators and commercial 3D and VR devices. Discussion: A brief introduction to the physiology of 3D viewing and surround visual field is presented. A history of stereoptical devices will be given, along with the problems that plagued them. Significant differences between optical (accommodation-vergence conflict, depth of focus), technological (resolution, refresh rates, flicker), and psychological problems (involvement, object consistencies) will be given. Virtual environment (VR) sickness depends on factors as realism, immersion and user presence, all required for a successful VR. Current display tech have more than one plague to hinder the perfect VR experience. The mismatch brain experience and expectation and the actual perceived input leads to cybersickness, as an extension to Reason model for motion sickness. The two has more in common than apparent, and it may have a more profound ontologic semnification that we are used to believe. Cybersickness is an unintended psychophysiological response to exposure to the perceptual illusions of virtual environments. Reported symptoms include stomach awareness, burping, salivation, drowsiness, nausea and occasionally even vomiting, as well as disorientation, dizziness, headaches, difficulty focusing, blurred vision and eyestrain. Some factors associated with the VR systems used can induce cybersickness. These include poor calibration and lags resulting from transport delay or update rate. Other factors are refresh rate, flicker, the realism of the display, and spatial properties such as field-of-view and viewing region. Human factors that influence the motion sickness are: degree of experience, participant’s interaction, immersion, flicker sensitivity, race, gender, hormonal status. Military experience with simulator sickness will be reviewed. The most encountered health effects as a general guideline for future studies (like a motion sickness chart): eye strain, general discomfort, nausea, focusing difficulty, headache. Successful usage of a VR display depends on habituation, with three key components: desenzitation, immersion an