Space Reshapes Astronauts’ Eyeballs



Since the earliest spaceflights, astronauts have experienced persistent vision problems on trips into orbit and extended stays at the International Space Station. The eye issues — known as SANS (Spaceflight Associated Neuro-ocular Syndrome) — is due to the lack of gravity changing the way fluids move around the body. It puts pressure on eyeballs, flattening them out and causing the optic nerve to swell. Microgravity literally reshapes eyeballs, and that’s bad. Many astronauts returning to earth after long-duration missions in space suffer from blurry vision that doesn't always get better. Dr. Benjamin Levine, a cardiologist working with NASA on addressing astronaut health risks, helped lead a new study that examined how a special high-tech sleeping bag might help prevent SANS. The sack is essentially a suction bag that uses a technique known as “lower body negative pressure” to prevent body fluids from building up in the region around the brain and eye. Spending just eight hours in the futuristic sleeping bag each night seemed to prevent the eye changes from occurring. While many of the problems associated with SANS seem to resolve once astronauts return to Earth, dealing with the issue in space is critical for longer space missions. With crewed missions to Mars a couple of decades away, solving the SANS issue will enable astronauts to travel without concerns about their vision.