Space: This is how an astronaut’s eyes change after almost a year in orbit

american astronaut Scott Kelly He spent 340 days in space, between 2015 and 2016, and underwent several major changes, including to his eyes. In the absence of severity, the changes she experienced were evaluated by the POT after his return to Earth.

For a year, the US aerospace agency examined Kelly’s readaptation to our planet.

And, for added scientific curiosity, Scott has a twin brother who is also an astronaut, Mark. While the first remained on the International Space Station, the second was on Earth. Then the comparisons between the two were made, leaving interesting conclusions.

The modifications in the eyes of astronaut Kelly

In the first instance, sight is one of the senses that undergoes the most changes in space. Not being in broad daylight, but enclosed in artificial light for all that time, the changes are clear. In addition, the absence of gravity affects the eyes.

The researchers highlight that the impact on the health of astronauts’ vision as a result of long-term space flight was previously known as Intracranial Pressure Syndrome. Over time, it was called Neuro-ocular Syndrome, or SANS.

Brandon Macias, director of NASA’s Johnson Space Center Cardiovascular and Vision Laboratory, spoke to CNN in 2021 about his research, published in JAMA Ophthalmology.

“The duration of the spaceflight mission can contribute to worsening ocular structural changes, such as inflammation of the tissues of the optic nerve head,” said Macías.

NASA tested not only Kelly, but also cosmonaut Mikhail Kornienko. Both were on the same mission, between 2015 and 2016, spending 340 days in space.

One of them (not identified in the paper) developed mild edema of the optic disc, which occurs “when the nerve fibers that enter the back of the eye swell, or when CSF (cerebrospinal fluid) accumulates around the fibers.” nervous”.

The NASA astronaut and the Russian cosmonaut spent 340 days on the International Space Station.

“If the swelling is serious and lasts a long time,” says Macías, “Visual function may be affected.”

The other person experienced optic disc edema in addition to progressive development of choroidal folds.

“The retina at the back of the eye is a soft layer,” says the NASA researcher. “Choroidal folds develop when this tissue wrinkles and becomes uneven. These folds can have different patterns depending on location and severity, and have the potential to affect visual function.”

Both professionals recovered after their return to Earth.

Changes in genetics: the comparison of the Kelly twins

But the changes in space are not limited to vision, but also to the chemical elements in the DNA.

In the comparison of the twins Scott and Mark Kelly, the great differences in the epigenetics of the genomes of both were observed.

NASA astronauts twins Scott (left) and Mark Kelly during a 2016 event.

The scientists found that there was less than a 5% difference in overall methylation between the twins during the mission, with the largest difference occurring 9 months later. when 79% of Scott’s DNA (the one that remained in space) was methylated, compared to 83% for Mark.

More than 90% of the genes that changed activity levels during Scott’s flight returned to normal six months after his return.

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