Braznor
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Brain scans of astronauts who have spent more than a month in space have shown serious damage in their eyeballs and brain tissue that could jeopardise the future of long-term space missions.
Researchers used MRI scans to examine the eyes and brains of 27 astronauts, who had flown long-duration NASA missions, and found a pattern of deformities in their eyeballs, optic nerves and pituitary glands that remains unexplained.
This ranged from a flattening and bulging of the eyeball to damage to the connections between the brain and the pituitary gland -- one of the key glands governing bodily functions, the researchers said.
The astronauts examined had been exposed to zero or micro gravity for an average of 108 days, either on space shuttle missions or on-board the International Space Station, Daily Mail reported.
The problems found in the astronauts are similar to those caused by intercranial hypertension -- a rare and dangerous condition where pressure inside the brain rises and presses against the skull and eye sockets.
Prof Larry Kramer, who led the tests at the University of Texas Medical School at Houston, said: "Microgravity-induced intracranial hypertension represents a hypothetical risk factor and a potential limitation to long-duration space travel.
"Consider the possible impact on proposed manned missions to Mars or even the concept of space tourism. Can risks be eventually mitigated? Can abnormalities detected be completely reversed?" he asked.
"The next step is confirming the findings, defining causation and working towards a solution based on solid evidence," he added.
The results, published in the journal Radiology, showed that nine of the 27 astronauts suffered an expansion of the cerebral spinal fluid space surrounding the optic nerve.
A flattening of the rear of the eyeball was found in six astronauts, while bulging of the optic nerve found in four astronauts. Three of them also had changes in their pituitary gland and its connection to the brain.With humans adapted over millions of years for livingwithin the pressure of Earth's atmosphere and gravity, it is unsurprising that space plays havoc with our systems.
In fact, with astronaut bodies trapped between conflicting gravity fields, lower gravity, and centrifugal forces, probably the most surprising fact is how well our bodies can endure space at all, the researchers said.
While these findings are not likely to put a hold on any current planned space missions, there may be implications to long-term travel in space as humanity continues to broaden our horizons, they added.
Meanwhile, William Tarver, head of flight medicine at Nasa's Johnson Space Centre in Houston, said no astronauts had been ruled out of flying after the findings, which he said were "suspicious but not conclusive of intracranial hypertension".
"Nasa has placed this problem high on its list of human risks, has initiated a comprehensive programme to study its mechanisms and implications, and will continue to closely monitor the situation," he said.
http://www.dailypioneer.com/home/online-channel/healh-a-fitness/49386-long-term-space-missions-cause-eye-problems-in-astronauts-.html
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