Astronauts-Report-Vision-Problems-After-Space-Missions,-NASA-Investigates

NASA Rushes to Fix Astronaut Vision Damage Before Mars 

A picture coming back to Earth, and everything it sees is different forever. For many astronauts, that dream is real. NASA revealed days ago that 70% of long-duration space fliers exhibit evidence of Space-Associated Neuro Ocular Syndrome (SANS). 

This condition is also described by symptoms similar to blurred vision, more specifically optic disc edema, and likely structural changes in the eye. As exploration gathers momentum and missions become longer, NASA is working diligently on how to mitigate or eliminate the long-term effects on astronauts.

The Disturbing Indicators: I Could Not Read My Notes


NASA astronaut Kayla Barron reported her post-flight vision experiences as feeling like she was seeing through a cloudy window on Earth. Medical imaging of her eyes demonstrated that both her eyeballs were flattened, and her optic nerves were swollen, both findings of Space Adapted Neural-Ocular Syndrome (SANS). In JAMA Ophthalmology in 2025, the journal published a study which stated:

  • 65% of astronauts had ongoing vision problems even after returning from six+ months in space.
  • 30% had signs of retinal damage caused by long-term exposure to microgravity, similar to patients with glaucoma.  

NASA's Dr. Steven Platts says that without a solution to this, if you start sending crews on three-year missions to Mars, humans will likely experience legal blindness.

The Danger of Zero Gravity: Fluid Shifts and Brain Pressure

In the home of microgravity, fluids in the body rise and increase pressure in the skull, which can crush optic nerves. The 2025 Fluid Shifts Study confirmed:  

  • Cerebrospinal fluid volume increases by 15% in space, compressing the eyes.  
  • Blood flow changes reduce oxygen to retinal tissue and hasten degeneration.  

Studies on countermeasures are underway to:  

  • Test Lower Body Negative Pressure (LBNP) suits to shift fluid.  
  • Develop artificial gravity chambers for use in future spacecraft during flight. 

Threat to Mars Missions: We Are Out of Time

NASA's Artemis program for lunar bases in 2030 is at risk; SANS endangers long-term mission viability. 2025 study findings:  

  • Mice exposed to 6 months of simulated spaceflight had irreversible optic nerve atrophy (Nature Communications).  
  • During research, a 40% decline in symptoms occurred for vitamin B12 supplements.  

Eyes on the Future: Protecting Astronauts' Vision 

For the prospect of interplanetary travel, it still must contend with the health of astronauts, and clearly, this is a tremendous obstacle. NASA's 2025 timeline for SANS solutions highlights the importance of this issue. It is possible that with new technologies such as artificial gravity and gene therapy, we will be able to see the dream of Mars on the horizon. 

At the same time, a study conducted by the Japan Aerospace Exploration Agency found that DNA and gene expression changes were found in the optic nerve and retina of mice after spaceflight, with preliminary evidence that artificial gravity may be able to mitigate some of these effects.

These aren't just medical challenges - they're astronauts struggling to read their kids bedtime stories after they get back. Every scientific advance makes Mars more reachable, but we need to safeguard our explorers' greatest tool - their ability to see the stars.