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The extended stay of two NASA astronauts aboard the International Space Station has exposed them to potentially permanent side effects of space travel.
New insights from eye health experts highlight vision damage as a serious and lasting condition that can affect astronauts long after their return from orbit.
Crew-9 mission members Suni Williams and Butch Wilmore initially planned for an eight-day assignment, but technical malfunctions stranded them in space for over nine months.
Persistent system failures left the astronauts in microgravity for an extended period before they safely returned to Earth earlier this week.
The human body, adapted to survive under Earth’s gravity, faces several physiological challenges when deprived of gravitational forces for long periods. One of the primary issues is the altered distribution of bodily fluids.
Tina Patel, a contact lens optician and eye health specialist at Feel Good Contacts, explains that in zero-gravity environments, fluids tend to shift upwards toward the head and upper body.
A condition called Spaceflight-Associated Neuro-Ocular Syndrome (SANS) causes the interior of the skull to flatten, leading to significant changes in astronauts’ vision.
Patel explains, “Extended time in microgravity not only alters the structure of astronauts’ eyes but also challenges their visual endurance.”
“This can cause the back of the eye to flatten, alter its shape, and in some cases, lead to optic nerve swelling, a condition known as papilledema,” she added.
These structural changes often result in visual impairment, difficulty focusing, and, in some cases, a permanent reduction in visual sharpness.
Research also suggests that cosmic radiation may damage the retina and accelerate eye aging, though further studies are necessary.
Upon their return, astronauts undergo extensive testing, including optical coherence tomography (OCT) scans, to assess potential eye damage.
“Some astronauts recover with prescription lenses, while others require ongoing monitoring due to persistent nerve swelling,” Patel noted.
NASA is actively testing protective measures to counteract such damage, including specialized suits that use negative pressure to redirect bodily fluids downward, mimicking the effects of gravity.
Meanwhile, teams of experts are developing eye training programs and medical interventions to aid astronauts in their recovery after space missions.
Despite these efforts, current prevention methods have yet to consistently speed up post-flight recovery for all astronauts.
While recovery can take weeks or even months, in some cases, the physical damage proves to be permanent.
“Some structural changes to the eye may, unfortunately, be irreversible,” Patel cautioned.
Medical experts are increasingly concerned about future missions to Mars, where astronauts will be far from immediate medical support.
And perhaps the most unsettling revelation?
Ophthalmological research suggests that Williams and Wilmore likely suffered significant, long-term vision deterioration during their 278-day mission.
What began as a short-duration space assignment became a prolonged endurance trial, posing serious risks of lasting health complications for the crew.
Ongoing research into astronaut recovery and continuous vision monitoring will shed light on the true human cost of deep space exploration.
Feature Image Credit: (NASA)
