  Using virtual reality (VR) head-mounted displays (HMDs) can induce VR
sickness. VR sickness can cause strong discomfort, decrease users' presence and
enjoyment, especially in games, shorten the duration of the VR experience, and
can even pose health risks. Previous research has explored different VR
sickness mitigation methods by adding visual effects or elements. Field of View
(FOV) reduction, Depth of Field (DOF) blurring, and adding a rest frame into
the virtual environment are examples of such methods. Although useful in some
cases, they might result in information loss. This research is the first to
compare VR sickness, presence, workload to complete a search task, and
information loss of these three VR sickness mitigation methods in a racing game
with two levels of control. To do this, we conducted a mixed factorial user
study (N = 32) with degree of control as the between-subjects factor and the VR
sickness mitigation techniques as the within-subjects factor. Participants were
required to find targets with three difficulty levels while steering or not
steering a car in a virtual environment. Our results show that there are no
significant differences in VR sickness, presence and workload among these
techniques under two levels of control in our VR racing game. We also found
that changing FOV dynamically or using DOF blur effects would result in
information loss while adding a target reticule as a rest frame would not.
