Effect of Repeated Space Flights on Ocular Tracking

This paper reports the results of studying the vestibular and ocular intersensory interactions and eye tracking function in 32 cosmonauts on maiden and repeated missions to the International Space Station. Mission duration ranged from 125 to 215 days. The cosmonauts were tested twice pre launch (baseline data collection) and on days R + 1/2, R + 4/5, and R + 8/9. Video oculography was used to test eye movements. It was found that in the majority of cosmonauts who had no experience of long-duration space missions the eye tracking function remained significantly impaired untill day R + 8/9. In cosmonauts who had already encountered microgravity, obvious changes in eye tracking were observed on day R + 1/2 only and, residual, on day R + 4/5. During post-flight recovery, a new eye tracking strategy was acquired only by cosmonauts who had the first experience of spaceflight microgravity.