A strategy to minimize these disturbances is to preadapt astronauts to specific combinations of altered sensory input simulating the transition between normal and microgravity. Specifically, post-flight vertical head movements are delayed and reduced in amplitude, compared to preflight data. In addition, smooth pursuit tracking movements were decreased in gain, resulting in poorer stabilization of gaze on moving targets. The aim of the proposed experiments is to evaluate the functional visual consequences of gaze destabilization that occurs when eye and head coordination or pursuit are degraded. If VOR and pursuit gains are abnormal, visual acuity is expected to be degraded until the retinal image velocity falls below a critical value and the target is imaged within a specific angular distance from the fovea.
Similar expectation holds for the response times for stereopsis.
However, stereopsis require that both eyes accurately fixate the stereotarget. Thus, discrepancies in the direction or velocity of gaze of the two eyes that do not decrease acuity can significantly impair stereo-performance. The initial steps towards conducting experiments proposed in this project have been successfully completed. These steps include experiment protocol design and development and configuration of software and hardware. An experiment system has been developed to measure visual acuity during large rapid gaze shifts.