The VOR gain is a ratio that compares the eye rotation rate (numerator) to counter the rotation and translation rate of the head (denominator). Because head motion has six DOFs, it is appropriate to break the gain into six components. In the case of head pitch and yaw, the VOR gain is close to . For example, if you yaw your head to the left at per second, then your eyes yaw at per second in the opposite direction. The VOR roll gain is very small because the eyes have a tiny roll range. The VOR translational gain depends on the distance to the features.
Recall from Section 2.3 that adaptation is a universal feature of our sensory systems. VOR gain is no exception. For those who wear eyeglasses, the VOR gain must adapt due to the optical transformations described in Section 4.2. Lenses affect the field of view and perceived size and distance of objects. The VOR comfortably adapts to this problem by changing the gain. Now suppose that you are wearing a VR headset that may suffer from flaws such as an imperfect optical system, tracking latency, and incorrectly rendered objects on the screen. In this case, adaptation may occur as the brain attempts to adapt its perception of stationarity to compensate for the flaws. In this case, your visual system could convince your brain that the headset is functioning correctly, and then your perception of stationarity in the real world would become distorted until you readapt. For example, after a flawed VR experience, you might yaw your head in the real world and have the sensation that truly stationary objects are sliding back and forth!5.2
Steven M LaValle 2020-01-06