Why does space flight affect vision?

2022-05-11 0 By

In an article titled “Now We Know Why Space Flight Affects Your Eyes,” published on the U.S. Universe Today website on January 9, Scott Allen Johnston wrote:Seventy percent of astronauts working on the International Space Station have swelling in the back of their eyes, resulting in blurred and impaired vision in space and when they return to Earth.Sometimes, it’s permanent.Understanding the way microgravity affects the eye, as well as the human body, is an important part of preparing for future long-duration space flights to the Moon and Mars.Poor vision is just one of the medical challenges humans face in space.Muscles weaken and bone density declines when they don’t have to fight earth’s gravity, and the intense radiation environment of space can lead to long-term diseases such as cancer.The ISS is largely designed as a microgravity laboratory, and many of the experiments conducted there are medical in nature, with the astronauts themselves as voluntary subjects — everything learned from these studies helps keep them and their companions safe.As a result, a large amount of medical data has been collected.This will reduce the risk for future astronauts.The effects of spaceflight on the eyes are known as space-related neuro-ocular syndrome (SANS).According to Dr. Mark Rosenberg, one of the study’s authors, space-related neuro-eye syndrome is so common that “when astronauts go into space, they actually carry extra glasses.They know their vision is going to go down there.”Physical changes in the eye include flattening of the sphere, damage to the retina and swelling of the nerves in the eye.For some astronauts, the eye recovers within a few weeks of returning to Earth, but the recovery process can sometimes take longer.According to the paper published by Rosenberg and colleagues, the root cause of space-related neuro-eye syndrome appears to be related to swelling of the vein behind the eye.Weightlessness causes changes in the distribution of blood in the body, with more blood flowing to the head and eyes than is normally the case on Earth.On Earth, gravity reduces blood flow to these areas.These results mean that “individuals with increased venous sinus compliance may be at increased risk for space-related neuro-ocular syndrome,” so pre-screening could help astronauts understand the risks to their eyes before they leave Earth.There is more to learn, of course.First, the team hopes to conduct more research on how the risk of space-related neuroeye syndrome might differ between men and women, using a larger sample of astronauts (the current study was based on two female astronauts and 10 male astronauts).They also hope to install a mobile magnetic resonance imaging (MRI) machine on the International Space Station to conduct brain scans in space.The post-flight scans performed in the current study left open the possibility that the changes they saw in the intracranial venous system occurred on return to Earth, rather than while in orbit.The team wanted the chance to rule that out.Disclaimer: This article is reproduced for the purpose of conveying more information.If the source is wrong or violated your legitimate rights and interests, please contact the author with proof of ownership, we will promptly correct, delete, thank you.Email address: newmedia@xxcb.cn