Astronauts who travel into orbit and put up with extended stays at the International Space Station (ISS) often face vision problems. This has been linked to the micro gravitational environment in spacecraft, which leads to swelling in the brain and optic nerves. The condition, known as spaceflight-associated Neuro-Ocular Syndrome,or SANS, may have a solution now. Researchers have come up with a sleeping bag which can regulate body fluids to prevent their accumulation in the brain during space missions.

Gravitational pull helps regulate how our body fluids function on Earth. The lack of gravity in space affects the normal fluid movement and causes the fluids to float up into the head. This movement puts pressure on eyeballs and flattens them. The optic nerve swells as a result of this.

NASA is trying to address various astronaut health risks, including SANS. Benjamin Levine, a University of Texas Southwestern Medical Center cardiologist working with NASA said, “This is perhaps one of the most mission-critical medical issues that have been discovered in the last decade for the space programme.”

Levine led a study published in the JAMA Ophthalmology journal. The study explored the possibilities of a high-tech sleeping bag which could prevent SANS. The experiment included a specialised sack-like structure which would be attached to a person from the waist down. This futuristic sleeping bag would act as a suction bag, functioning with a technique called “lower body negative pressure.” This would prevent body fluids from floating up and accumulating towards the region around the brain and the eyes.

The experiments with this sleeping bag included 10 subjects — five male and five female — who would get into bed and lie flat for three days at a stretch on Earth. After three days, researchers noticed a change in the shape of eyeballs. This occurred because the subjects weren’t allowed to stand, which relieves pressure from the brain.

Then, they tried the sleeping bag on the subject. Researchers found that just eight hours in the sleeping bag each night prevented the change in eyeball shape.

Most problems associated with SANS get resolved after astronauts come back to Earth after a few months’ stay at the ISS. However, the problem would be persistent if astronauts had to make a two-year trip to Mars. Hence, solving the SANS problem is important to enable longer space travel for astronauts.