13.03.2012

Space travel "harms astronauts" eyes"

Space travel "harms astronauts" eyes"

By Adrian Galbreth

Space may be the final frontier, but for the brave men and women who boldly go where no man has gone before, the effects of space travel may be having a detrimental impact on their eyes, a new study has suggested.

Researchers at the University of Texas Medical School at Houston have published research which suggests that prolonged periods of time in space cause optical abnormalities similar to those that can occur in intracranial hypertension of unknown causes.

Analysis of the eyes and brains of 27 astronauts using magnetic resonance imaging (MRI) identified this condition, a potentially serious one in which pressure builds within the skull.

The MRI data appears online in the journal Radiology and reveals how a team of researchers performed MRIs and analyzed the data on astronauts who were each exposed to microgravity, or zero gravity, for an average of 108 days while on space shuttle missions and/or the International Space Station (ISS).

Eight of the 27 astronauts underwent a second MRI exam after a second space mission that lasted an average of 39 days, with the results revealing various combinations of abnormalities following both short- and long-term cumulative exposure to microgravity, which is also seen with idiopathic intracranial hypertension.

Dr Larry Kramer, professor of diagnostic and interventional imaging at the University of Texas Medical School at Houston, said the changes that occur during exposure to microgravity may help scientists to better understand the mechanisms responsible for intracranial hypertension in non-space travelling patients.

However, he noted: "Microgravity-induced intracranial hypertension represents a hypothetical risk factor and a potential limitation to long-duration space travel."

In response to the study, Dr William Tarver, chief of flight medicine clinic at NASA/Johnson Space Center, said NASA has placed the problem high on its list of human risks and initiated a "comprehensive programme" to study its mechanisms and implications, and will continue to closely monitor the situation.

by Martin Burns


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