It has been well documented that space does some pretty strange things to astronauts' bodies - they come back 2 inches taller and with far less muscle mass. However, there is a subtle change that has been noted over the years that is a big concerning: space is ruining otherwise perfect eyesight.
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It isn't just a small percentage of astronauts either - some 80 percent of astronauts who have come back from long-term missions have symptoms of a confusing eyes condition that causes them to be nearsighted, according to the Washington Post.
While it is true that astronauts have to have 20/20 vision by the time they go into space, they are allowed to have corrective eye surgery like LASIK. Still, when they come back they are completely nearsighted - so what is NASA going to do about this, especially if they want to stay on track with their plan to get humans to Mars in the 2030s?
They might already be on their way to solving the problem, however. John Phillips was the first to notice the problem after being on board the International Space Station in 2005. His vision suffered throughout the mission, but not enough to let mission control know. When he was tested after his return to Earth, they found that his vision was 20/100 - a far cry from the 20/20 he went in with. He was only in space for six months.
The actual shape of his eyes changed as well.
"The backs of his eyes had gotten flatter, pushing his retinas forward. He had choroidal folds, which are like stretch marks. His optic nerves were inflamed," reports said.
NASA thought that it was just him until they found that a majority of astronauts came back with some sort of vision problem.
They've given the condition a name: "visual impairment intracranial pressure" syndrome or VIIP for short. The name comes from the theory that the problem is caused by pressure building up in astronauts' heads thanks to a lack of a gravity. Since gravity brings fluid toward our feet, astronauts often come back with fluid shifted into the brain. This puts an enormous amount of pressure onto the eyeballs, changing their shape. Scientists hypothesize that the flattening of the eyeballs is leading to distortion.
But there is another problem: we aren't able to monitor the syndrome. In order to work on it, they'd have to perform a spinal tap and/or drill a hole in someone's head. These aren't the best things to do while one is in space. Still, NASA is going to have to figure out how to take care of the problem. They are testing options now, including wearing something called a Russian Chibis suit, which helps simulate gravity.
All research is still early and there will need to be a lot more, but John Charles who is the chief scientist at NASA's Human Research Program said that restoring the flow is positively affecting the eye.
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Whatever the case, let's hope they fix the problem or we will need to have an ophthalmologist in space sometime soon.