How Does NASA Study Vision and Cognitive Changes in Space? – Thursday, June 11, 2026

Did you know 70% of astronauts experience swelling in the back of their eyes during spaceflight? This is known as SANS, or Spaceflight Associated Neuro-ocular Syndrome. Scientists believe it results from upward fluid shifts in weightlessness. But a key question remains: Do these changes fully resolve after flight or do they persist? To find out, a new study from NASA’s Human Research Program is looking at the long-term effects of flight-induced eye and brain changes in astronauts up to five years after their mission. Both active and retired crews will go through a series of exams that assess visual fields, eye pressure, cognitive function, and more. By keeping an eye on the vision and brain health of spacefarers, NASA will be better equipped with the protocols needed to ensure humans are healthy on missions to the Moon, Mars, and beyond. Join NASA as we go forward to the Moon and on to Mars -- discover the latest on Earth, the Solar System and beyond with a weekly update in your inbox. Subscribe at: https://www.nasa.gov/subscribe