Why Do Astronauts Suffer Deteriorated Eyesight After Spending In Space? Scientists Reveal

It is reported that about two thirds of astronauts have deteriorated eyesight after spending time in space. The scientists are trying to know the reasons behind the impairment of astronauts' vision ever since and now they finally figured it out why.

NASA astronaut Scott Kelly was chosen to be America's first astronaut to spend a year in space. He said upon returning to Earth, he was forced to wear reading glasses although before the expedition he has an exceptional vision. Meanwhile, John Phillips, who also spent time in space in 2005, had experienced blurry vision and NASA confirmed that his vision had gone from 20/20 to 20/100 in just six months.

Dorit Donoviel from the U.S. National Space Biomedical Research Institute told The Guardian that nobody has gone two years with exposure to this and the concern is that they have loss of vision. She further said that it is catastrophic for an astronaut.

NASA has been trying to determine the cause of the loss of vision of astronauts. Currently, researchers from the University of Miami have examined and studied what is causing vision problems in astronauts. In the study, the team compared before and after the brain scans from seven astronauts who had spent many months in the ISS and compared them to nine astronauts who made short trips to and from the U.S. space shuttle.

The results showed that the difference between the two was that the astronauts who spent much in space had more cerebrospinal fluid (CSF) in their brains than the astronauts with short trips. According to the researchers, not vascular fluid is the cause of the vision loss.

The CSF is significant for cushioning the brain and the spinal cord and also distributes nutrients in the body and removes waste. In microgravity of space, the CSF system starts to fail. Noam Alperin, one of the researchers, said that on Earth, the CSF system is built to accommodate these pressure changes. But in space, the system is confused by the lack of the posture-related pressure changes. This high orbital CFS volume causes the CSF pooling around the optic nerves in the part of the skull that holds the eye.

The findings of the study were presented at the annual meeting of the Radiological Society of North America in Chicago this week. The findings were to be reviewed still, according to Science Alert.