Spaceflight associated neuro-ocular syndrome

Spaceflight associated neuro-ocular syndrome (SANS), previously called spaceflight-induced visual impairment, is hypothesized to be a result of increased intracranial pressure (ICP), although experiments directly measuring ICP in parabolic flight have shown ICP to be in normal physiological ranges during acute weightless exposure. The study of visual changes and ICP in astronauts on long-duration flights is a relatively recent topic of interest to space medicine professionals.

Source: Wikipedia — Spaceflight associated neuro-ocular syndrome (CC BY-SA 4.0)