Astronauts who return to Earth after long-duration space missions suffer from untreatable nearsightedness. Scientists have now isolated the cause, but finding a solution to the problem will prove easier said than done.
The problem, say researchers from the University of Miami Miller School of Medicine, has to do with volume changes in the cerebrospinal fluid (CSF) found around the brain and spinal cord. Prolonged exposure to microgravity triggers a build-up of this fluid, causing the astronauts’ eyeballs to flatten, which can lead to myopia. A build-up of CSF also causes astronauts’ optic nerves to stick out, which is also not good, as the optic nerve sends signals to the brain from the retina. This is causing nearsightedness among long-duration astronauts, and it’s problem with no clear solution in sight (so to speak).