NASA has been worried for a while now about astronauts returning from space with blurred vision and other eyesight problems. A new study in the journal Radiology might help explain why: Brains scans of 27 astronauts who had been on missions longer than a month showed that they had abnormalities in their eyeballs and nearby nerves and glands, reports the Guardian. The symptoms resemble those of a condition known as intracranial hypertension, caused by pressure inside the skull.
"Consider the possible impact on proposed manned missions to Mars or even the concept of space tourism," says the lead University of Texas scientist. "The question now is, do these changes plateau after six months, or will longer-duration missions mean there will be even more astronauts experiencing more severe abnormalities? The next step is confirming the findings, defining causation, and working towards a solution based on solid evidence." NASA is now looking into the issue, as are European, Russian, Canadian, and Japanese space agencies.