Another factor contributing to discomfort when operating a
mouse and a trackball is the lack of precision in generating trajectories,
which originate in the mismatch between the coordinate
system of a display and the body-fixed coordinate system
used when operating the devices (Lee and Bang, 2015). Lee et al.
realized a technical solution for the mouse, compensating for the
effect due to the mismatch of the coordinate systems. Following
the results of the subjective ranking, we can conclude that input
devices used in similar conditions, such as in self-testing vision
screening, should preferably be equipped with a limiting frame or
with force feedback to re-center the device after pointing is
completed.