Four parameters of the visual system, i.e., far point, resting vergence, resting focus, and near point are described along with a variety of adaptable oculomotor systems.
The conditions productive of adaptation of the vestibulo-ocular response (VOR), optokinetic response (OKR), accommodation, vergence, and other systems are discussed in relation to certain characteristics of teleoperator displays. Since adaptation shares a common set of antecedents with asthenopia (eye strain) and motion sickness, the possibility of illness, including ataxia, from exposure to teleoperator displays also will be discussed.
It is likely that visual effort or stress is related to the degree to which the oculomotor control system departs from its resting level in order to maintain clear, single and stable vision. However, since resting levels, the rate of adaptation, and the very ability to adapt are controlled by parameters that vary widely among individuals, preventive measures require highly specific knowledge of these visual system characteristics of individual human operators.