Astronauts are meant to be not just the most intelligent people, but also some of the most physically fit. With the demands of missions in the International Space Station, NASA's above-earth scientists are trained for the most rigorous environments.
Naturally, they are at the best upon their departure. However, 80 percent of astronauts have complained over the years about their vision getting worse after International Space Station missions.
According to Press Herald, the first recorded incident involved astronaut John Phillips. He was meant to stay in the ISS from April to October in 2005. Midway through his stay, he realized that his eyesight was getting blurry and that his vision was getting impaired. As far as Phillips recalls, he did not report the same to NASA. "I thought it would be something that would just go away and fix itself when I got to Earth."
However, at his post-flight physical, NASA found out that his vision had gone from 20/20 to 20/100 in only six months. What followed was a list of tests, including MRIs, retinal scans, a lumbar puncture and neurological tests. Unfortunately, not only had Phillips vision been impaired, but his physical eyes had gone through changes as well.
His retina was pushed forward due to the back of his eye getting flatter. His optic nerve was inflamed as well. Lastly, he had choroidal folds, which are stretch marks at the back of one's eye.
As Stuff.Com reports, the leading theory to explain this anomaly is called the Visual Impairment Intracranial Pressure syndrome (VIIP). On Earth, gravity pulls bodily fluids down towards the ground. However, the lack in gravitational force in space causes an excess amount of fluid in the skull. This then increases pressure on the brain and the back of the eye.
It is a theory at this point since astronauts can only be tested on once they get back to the Earth. "There's the risk for infection and just doing the procedure, quite frankly, in space is difficult," admits JD Polk, a senior flight surgeon at NASA.
It is also difficult to study the effects here on earth, because of the presence of gravity. There are too many factors that cannot be controlled in either environment to truly test theories.
However, Ross Ethier, a biomedical engineer at Georgia Tech, is currently working on a solution, namely a device that could pull back fluid down to legs in space. The trouble at this point now is determining how long the individual needs to wear it, as the device is big and uncomfortable.
