According to a new study, 70% of astronauts who have spent between six and 12 months aboard the International Space Station (ISS) experienced significant changes to their vision due to a condition called "spaceflight-associated neuroocular syndrome," or SANS.
SANS involves symptoms like swelling of the optic nerve, flattening at the back of the eye and general changes in vision. It occurs when fluids in the body shift while exposed to microgravity conditions, thereby putting pressure on the eyes.
