Space News Update: Lack Of Gravity May Cause Astronauts' Eyesight To Deteriorate

Space missions have been growing not just in number but also in the time spent in space. Because of this, astronauts started to notice something that troubled them. They found that their time in space may be causing their eyesight to worsen.

A report by Popular Mechanics found that John Phillips, an astronaut who has spent over six months on the International Space Station in 2005, claimed he started to have problems with his eyesight while he was in space. However he was hesitant to report it.

"I'm not sure if I reported that to the ground," he said. "I think I didn't. I thought it would be something that would just go away, and fix itself when I got to Earth," Phillips said.

During the routine post-flight medical exam, doctors discovered that Phillips' once 20/20 eyesight had deteriorated to 20/100. Another surprising thing is that, Phillips was not the only one who experienced deteriorated eyesight.

According to Gizmodo, researchers found that about 80 percent of astronauts suffer from a condition known as visual impairment intracranial pressure syndrome (VIIP). Experts believe that this condition, like other conditions suffered by astronauts, may be connected to the lack of gravity.

Researchers explained that fluid that normally accumulated in the lower half of the body, because of gravity, has a tendency to flow upward which can cause an increased pressure on the brain. An astronaut named Scott Kelly was found to have about two-liter bottle's worth of liquid that shifted to his brain during his time in space. This would have caused more pressure on the back of the eyeball, which could have caused it to flatten and push the retinas forward, thus distorting the eyesight. In Phillips' case, it was found that his optic nerves were inflamed and had choroidal folds.

Meanwhile, NASA thought Phillips' case was an isolated one until researchers found evidence that VIIP is also experienced by other astronauts. The Washington Post reported that VIIP has now been recognized as a widespread problem, and experts have been struggling to understand what's causing it.

Researchers said the theory that fluid accumulates in the skull during spaceflight has not been tested yet since the only proven methods to measure intracranial pressure are spinal tap or drilling a hole into the skull, which are both invasive.

"There's the risk for infection and just doing the procedure, quite frankly, in space is difficult," said J.D. Polk, a senior flight surgeon at NASA. "Having to anchor somebody and do a spinal tap in space is not something we would relish."

Researchers are giving their all to understand the syndrome here on Earth by using different methods such as, tilting bodies downwards to simulate the pressure on the eyes and putting people in parabolic flight, which simulates zero gravity for a few seconds. However, none of these methods generated helpful information.

VIIP is considered to be one of the major obstructions in NASA's plans to send humans to Mars by 2030 considering that the trip would las six to nine months, and NASA can't have astronauts with deteriorating eyesight during the trip.

Ross Ethier, a biomedical engineer at Georgia Tech, is designing a device that would make bodily fluids stay into the lower extremities during the flight. The size of the device and how long astronauts would have to wear it each day has not been determined yet. However, experts say that there is a potential that technology like ultrasound or cranial implant could help them study the pressure in the brain during space flights without having to perform risky and invasive in-flight surgery.

For now, VIIP remains to be the first of many conditions we'll discover as people stay in space for longer periods of time.