Lower-body negative pressure decreases noninvasively measured intracranial pressure and internal jugular vein cross-sectional area during head-down tilt.

Long-term spaceflight induces a near visual acuity change in ~50% of astronauts. In some crew members, postflight cerebrospinal fluid (CSF) opening pressures by lumbar puncture are as high as 20.9 mmHg; these members demonstrated optic disc edema.