Extended space missions may significantly impact the eye health of astronauts and lead to vision changes, a new study has confirmed. About 70% of astronauts associated with the International Space Station (ISS) suffer from SANS -- spaceflight-associated neuro-ocular syndrome, according to the Universite de Montreal study.
Santiago Costantino, an ophthalmologist, who led a team of researchers for the study blamed biomechanical changes for the disorder. The team analysed data from 13 astronauts who spent 157 to 186 days on the ISS. Three ocular parameters - ocular rigidity, ocular pulse amplitude and intraocular pressure - were compared before and after the space missions.
The findings revealed that astronauts experienced a 33% reduction in ocular rigidity, an 11% drop in intraocular pressure and a 25% decrease in ocular pulse amplitude. Additionally, they exhibited symptoms such as shifts in focal field and shrinking eye size. Rare cases included optic nerve swelling and retinal folds.
Mr Costantino explained the reason for these vision-related problems. "Weightlessness alters the distribution of blood in the body, increasing blood flow to the head and slowing venous circulation in the eye," he said.
While these vision changes might seem alarming, they are not as concerning. Research has indicated that while 80 per cent of the astronauts experienced at least one visual symptom, their eyes eventually returned to normal after returning to Earth.
In most instances, wearing corrective glasses was enough to counteract the vision issues that arose during their time on the ISS.
According to Earth.com, advanced imaging technology and portable diagnostic tools could assist astronauts in detecting early signs of SANS. Timely intervention can even prevent such eye conditions.
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