One can imagine that flying up to space can do peculiar things to one's body. And, in the case of a couple of astronauts who have returned, to one's mind.
Yet new research from NASA suggests that prolonged periods in the bluey-black beyond might cause serious damage to your eyes.
Space.com offers a chilling view of brain scan tests performed on 27 astronauts who had spent an average of 108 days away floating up there.
As they used to say in soothing TV commercials, I am not a doctor. However, the conclusion that a third of the astronauts had an increase in the cerebrospinal fluid space that surrounds their optic nerve does not sound like a good step for mankind.
Especially as another 22 percent seemed to have endured a flattening of the back of their eyeball.
There were also significant incidences of bulging optic nerves and pituitary gland abnormalities. It seems that such symptoms are often associated with idiopathic intracranial hypertension--essentially increased pressure around the brain.
The research, published in the journal Radiology, offers the slight problem that these astronauts had all been in space before, so there was no control data against which to compare these results.
NASA, for its part, is aware of the problems some astronauts have experienced with their eyesight. The chief of the flight medicine clinic at NASA's Johnson Space Center in Houston, William Tarver, told Space.com: "NASA has placed this problem high on its list of human risks, has initiated a comprehensive program to study its mechanisms and implications and will continue to closely monitor the situation"
It is already known that space travel isn't so good for your bones. However, if increased time in space is shown, one day, to have an exponential effect on eyesight, then it will seem almost tragic.
It won't stop humans wanting to go up there and explore, though. One example of how humanity will take vast risks in order to achieve something extraordinary is the Goldman experiment.
A researcher called Bob Goldman asked athletes in the 1980s if they'd take drugs to achieve greatness, even if those drugs would kill them in five years. More than half said they would. These results have been replicated every two years.
So what's a few eye problems when compared with the chance to advance mankind? Very little, I suspect.