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Prolonged space travel may damage astronauts' vision

The analysis revealed that 30 percent of the short-mission astronauts and 60 percent of those on long-missions had experienced a slight degradation in their vision.

NASA researchers are investigating a new eye condition that has the potential to permanently impair vision of astronauts who spend prolonged time in space explorations.

Astronauts who've spent months on the International Space Station (ISS) reported blurred vision, a problem that has the potential to endanger space voyages to Mars in years to come.

So serious is the threat that the space agency flew special eyeglasses made by Superfocus to ISS for astronauts, while researchers delve into the issue.

Dr. Rich Williams, NASA's Chief Health and Medical Officer, stated, "We are certainly treating this with a great deal of respect.

"This [eye condition] is comparable to the other risks like bone demineralization [loss] and radiation that we have to consider … It does have the potential for causing mission impact."

"Some of it is reversible. Some people, it reverses and they come back to the same level that they were at pre-flight. Others have not been reversible."-- Chief NASA Astronaut Peggy Whitson

300 astronauts studied
With the aim to understand the risk of eye damage associated with long space missions, a team of 17 researchers conducted a study.

They reviewed post-flight questionnaires of 300 astronauts who had served on missions that lasted between two weeks to at least six months.

The analysis revealed that 30 percent of the short-mission astronauts and 60 percent of those on long-missions had experienced a slight degradation in their vision.

Chief NASA Astronaut Peggy Whitson said, "Some of it is reversible. Some people, it reverses and they come back to the same level that they were at pre-flight. Others have not been reversible."

A plausible explanation
No one has been blinded in five decades of space travel, but astronauts have reported problems with long-distance vision while in space

Moreover, there is one person who is still suffering from eye problems even five years after returning to Earth.

Though the exact cause of deteriorating eye sight is ambiguous, it is believed to be similar to a condition called papilledema and could be triggered by a spike in the spinal-fluid pressure on the optical nerve due to microgravity.

Dr. Bruce Ehni, a neurosurgeon involved with the issue, said, "No one has been in space long enough to know how bad this papilledema can get.

"When they [NASA] start going [to] long-distance [destinations] like Mars, you can't end up having a bunch of blind astronauts."

The findings have been published in the journal 'Ophthalmology.'