Article Preview
TopLiterature Review
Virtual Reality sickness (or VR sickness) is also known as motion sickness, simulator sickness and Cyber Sickness. VR Sickness occurs when a user moves in a virtual environment (VE) and nausea, asthenopia, and dizziness are experienced. The underlying mechanism of VR Sickness is not yet clear (Davis et al., 2014). However, the sensory inconsistency theory to the visual inductive self-movement sensation (i.e. visual vection) is cited as a possible cause (Seno et al., 2017). Vection can be described as feeling similar to ‘being in motion’ when in fact one is not moving at all. An example of vection is when one is sitting on a stationary train at a train station when suddenly the adjacent train starts to move, and for a brief moment you believe it is your train that is moving. The factors that induce vection include the position, color of the stimulus to the field of view, and roughness of the stimulus (Tambovtsev et al., 2016).
A recent comprehensive review of CyberSickness by Davis et al. (2014) reveal that “the issue is complicated as experiences of cybersickness vary greatly between individuals, the technologies being used, the design of the environment and the tasks being performed.”
VR sickness is affected by a sense of touch and position (termed Somatosensory), balance (the Vestibular system in the ear passage), and muscles that control eye movements (termed Oculomotor). Tambovtsev et al. (2016) suggest that in order to avoid VR sickness people need a 'frame of reference' such as an horizon or a control panel/ dashboard. It is said that if a user can predict the surrounding environment by deploying an object in a stable position, such as a driver's seat of a car or the cockpit of a spacecraft, users only feel a mild version of VR sickness.
A number of methods have been utilized to reduce VR sickness. Fernandes et al. (2016) showed that VR sickness is reduced by controlling the Field of View range when moving in a virtual environment. There were thirty (30) subjects. They experimented over two sessions on separate days. The experiment consisted of subjects moving around in the virtual environment while a controlled field of view was automatically applied (see Figure 1). The measurement method was analyzed by the Simulator Sickness Questionnaire (see below), the Average Discomfort Score which calculated the weighted average with time, and the Relative Discomfort Score (a consideration of the time spent by subjects in the virtual environment).