Have you heard about the vision problems astronauts have in space?
Yep, a few times actually! I wrote about it previously (here and here) but new research suggests the reason for the vision deterioration is linked with a lack of a day-night cycle in intracranial pressure (ICP). On earth, ICP changes depending on if we are standing (lower ICP) or laying down (higher ICP). In a zero-gravity situation, there is no fluctuation in ICP like on earth. “These findings suggest the human brain is protected by the daily circadian cycles in regional ICPs, without which pathology may occur.”
What is the syndrome called?
Visual Impairment Intracranial Pressure syndrome, or “VIIP” and it is considered to be NASA’s top health risk for long-duration space flight. The findings in this syndrome are papilledema, flattening of the globe of the eye and dilation of the optic nerve sheath.
Investigators suggest, “it might be possible to prevent the problem by using a vacuum device to lower pressure for part of each day”.
Another interesting takeaway:
Clinically, female astronauts appear to have less severe visual impairment during long duration space missions than men.