Why Are Astronauts Affected by Visual Damages?

A new study reveals the cause of visual damages in astronauts. Those astronauts who set off for extended missions in space develop an individual visual issue. Based on data from a new study presented at the Radiological Society of North America (RSNA), this eye problem was unveiled to be related to the volume alternations in the fluid which surrounds the spinal cord and the brain.

After conducting many types of research to discover a cause of the visual damages, scientists from NASA have found a pattern of astronauts’ visual problems due to long space missions. The blurry vision of astronauts has unveiled that their eyeballs began to flatten at the back, also presenting a sort of inflammation of the optic nerves. This syndrome called visual impairment intracranial pressure (VIIP) was registered to affect almost two-thirds of space-travelers after they had spent long periods aboard the International Space Station.

Noam Alperin, the lead author of the study and also a professor of radiology and biomedical engineering at the University of Miami Miller School of Medicine in Miami, Florida, has argued that scientists did not initially know what is the cause of the disease. By 2010, this eye problem rose concerns among specialists due to the significant number of astronauts suffering from it. What is more, it was proved that some astronauts had experienced some structural changes which were not completely reversible when they got back home.

Some specialists have thought that the most significant source of the visual damages could lay in the shift of vascular fluid which moved upward in the body. This ascending of the fluid usually happens when astronauts spend extended periods in space’s microgravity. The group of researchers conducted by Dr. Alperin had investigated a new possible source which could influence the development of visual damages.

They believed that cerebrospinal fluid (CSF) which represents the fluid which protects the spinal cord and the brain and at the same time fuels the circulation of nutrients, removing waste matters could be responsible for eye impairments. The CSF system is generated to allow significant changes under hydrostatic pressures. Nevertheless, space’s microgravity can alter this system, representing a new challenge.

Dr. Alperin has asserted that the CSF system on Earth is bound to permit the changes in pressure, but in space, this system becomes confounded due to the lack of the pressure changes related to the posture of the body.

Image courtesy of: public domain pictures