An OCT study on spaceflight crew members found ocular morphology alterations potentially related to weightlessness and chronic headward fluid shift were not reversed by short-duration lower body negative pressure countermeasures.
The NASA Fluid Shifts Study included 14 crew members. Preflight and postflight OCT scans were obtained at NASA’s Johnson Space Center, and other scans were acquired during spaceflight under normal weightless conditions and during 10- to 20-minute sessions of 25 mm Hg lower body negative pressure (LBNP) application.
The mean flight duration was 214 days. Ocular