“Blindness”
Hadn’t heard about this so did some research.
Not really blindness but a change in the shape of the eye so a change in their glasses prescription. Has to do with intracranial pressure.
Interesting. Thanks.
While relatively short LEO flight eye problems can be fixed by an earthly eye doctor, there are none on Mars. Changes are worse over time. Long duration trips in years like to Mars would have them arrive effectively blind.