One serious drawback for astronauts who spend long periods in space is that they often return to Earth with degraded vision, and a new study may have pinpointed the problem. It's a buildup of spinal fluid around the eyes, say researchers from the University of Miami. This cerebrospinal fluid is the stuff that cushions the brain and keeps it safe when we move around, but the lack of gravity in space seems to throw it out of whack, reports the BBC. Instead of being evenly distributed, it tends to pool around the eye cavities and exert pressure on the eyeballs, flattening them, explains Vice. Most astronauts who spend months in space end up with blurrier vision, and the condition isn't always reversible, notes a post at Phys.org.
"We saw structural changes in the eye globe only in the long-duration group," says lead author Noam Alperin. "And these changes were associated with increased volumes of the CSF. Our conclusion was that the CSF was playing a major role in the formation of the problem." The findings, presented at the annual meeting of the Radiological Society of North America, are the first concrete evidence that CSF is the culprit, and they could help NASA figure out how to remedy the problem. A larger study is now in the works, but this first one is "timely and significant," given the push toward longer-duration missions, adds a post at Universe Today. (Check out some "weird music" from the dark side of the moon.)