SCIENTIFIC AMERICAN – In the next 15 years, NASA hopes to launch a mission to Mars. But the long journey poses a challenge — not least from a mysterious ailment that alters astronauts’ eyesight.
Spending long periods in the microgravity of space can lead to changes in the eye, including swelling in the region where the optic nerve extends to the brain; flattening of the rear of the normally round organ; wrinkles that emerge at the back of the retina; and shifts in the refractive index that change how the eye focuses.
Together, these changes have been dubbed spaceflight-associated neuro-ocular syndrome (SANS). Despite more than a decade of study, researchers still don’t know exactly what causes it, who’s at highest risk or how to prevent or treat it.
Tyson Brunstetter, an aerospace optometrist at the Johnson Space Center in Houston, Texas, was serving in the US Navy when he read the first report on the syndrome, in 2011.
He found the condition fascinating, but did not consider it a major obstacle to spaceflight. “I said, ‘It’s NASA. They’ll figure it out in six months’. And yet here I am, part of the team trying to figure out what exactly is going on.”
“Scientists insist that the more intelligent the monkeys become, the more likely they will be able to survive the six-month journey to Mars.” – Cruelty Free International
NASA considers SANS one of its ‘red risks’ for a Mars mission, owing to its potential severity and the number of astronauts that could be exposed. Other high-priority risks include radiation exposure, changes in mental health and difficulty maintaining adequate nutrition.
Although some changes have been detected in astronauts’ eyes after as few as ten days in space, physicians think that the risk increases as more time is spent in microgravity.
So far, SANS has been an issue mostly for people doing six-month stints on the International Space Station (ISS) …
