Astronaut vision may be impaired by spinal fluid changes: Study

Astronaut vision may be impaired by spinal fluid changes: Study A recent research has found that astronauts may experience blurry vision and impaired eyesight after long spaceflights due to changes in spinal fluid that occur while in microgravity.  The research was presented at annual meeting of the Radiological Society of North America (RSNA), Chicago on 28 November 2016. The syndrome known

as 'Visual Impairment Intracranial Pressure' (VIIP) was reported in nearly two-thirds of astronauts after long-duration missions aboard the International Space Station (ISS).

• Some of the astronauts experienced severe structural changes that were not fully reversible upon their return to Earth.

• The problems includes flattening at the back of their eyeballs and inflamed optic nerves, which can lead to far-sightedness.

• Longterm space flyers also had significantly increased post-flight flattening of their eyeballs and increased optic nerve protrusion.

• On Earth, this spinal fluid system is designed to accommodate changes whether a person is sitting, standing or lying down. But in space, the system is confused by the lack of the posture-related pressure changes.

About the research

• The research was carried out by lead researcher Noam Alperin, professor of radiology and biomedical engineering at the University of Miami Miller School of Medicine.

• Researchers initially thought that the problems were due to changes in the way blood is distributed in the body in microgravity, with more fluid lingering around the head area.

• But this was later falsified when Alperin and colleagues studied before and after brain scans on seven astronauts who had spent multiple months at the orbiting space station.

• They then compared the scans of these seven astronauts to nine astronauts who made short trips up and back aboard the US space shuttle, which retired in 2011.

• They found that long-duration astronauts had significantly more cerebrospinal fluid (CSF) in the brain.

• This fluid typically helps cushion the brain and spinal cord while circulating nutrients and removing waste materials.

The research offers the first quantitative evidence on the fact that cerebral spinal fluid plays a direct role in visual impairment syndrome.

NASA is currently studying ways to counteract these eye problems, as it is working towards sending people to Mars by 2030s on months or years-long missions.