United States researchers are teaming up with the Polaris spaceflight program to better understand why astronauts experience vision changes – and even significant vision loss – when they return to Earth.
More than 70% of astronauts experience a phenomenon known as Spaceflight Associated Neuro-Ocular Syndrome, or SANS. Researchers at the Augusta University said the changes in vision “start happening on day one”.
“We suspect it has to do with a shift in cerebrospinal fluid in the optic nerve sheath. On Earth, gravity pushes that fluid down and it drains out, but in space, it floats up and presses against the optic nerve and retina,” the University’s Dr Matt Lyon said in a news release.1
With the help of portable, handheld ultrasound machines, Dr Lyon’s team hopes to not only figure out the mechanism behind the changes, but also be able to predict which astronauts will be most likely to experience them.
The researchers are using ultrasound machines to screen astronauts and determine who among them may already have incompetent or damaged optic nerve sheaths. They suspect that those are the ones who will be more susceptible to SANS-associated vision changes.
The researchers are also training Polaris Dawn crewmembers to use the ultrasound machines to measure both fluid and pressure in real time during spaceflight.
Next steps could include working to develop and fine tune countermeasures that would decrease fluid volumes in the head during spaceflight.
Reference
- Augusta University, MCG physicians working to help prevent vision loss associated with space travel (news release, 22 Aug 2024) available at: eurekalert.org/newsreleases/ 1055276 [accessed 28 Aug 2024].