Credit: © DLR. All rights reserved
A large number of eye examinations await the test persons in the current bed rest study. The image shows the measurement of the change in eye axis length by means of the so-called objective refraction to exclude a shortening of the eyeball.
Living in space puts an enormous strain on the body. Among other things, astronauts are exposed to space radiation and experience their muscles deteriorate and body fluids shift towards the head. To protect against the radiation, international research is being conducted on protective vests, for example in the MARE mission. Effective training programmes have been developed to combat muscle atrophy, so that today astronauts hardly have any difficulties upon returning to Earth, even after spending months on the International Space Station (ISS). However, the increased pressure in the head due to the changed fluid distribution can lead to permanent problems – especially for the eyes. Time and again, space travellers report a deterioration of their eyesight, with about 70 percent experiencing eye changes, either temporarily during the stay in space or permanently.
The causes are still unclear. There are some theories but no evidence explaining why this affects some astronauts and not others, but it is clear that the eye condition is a significant risk. If we think about the future of human spaceflight with missions to the Moon and Mars, stays in weightlessness will last longer and longer. Through all of this, the health and safety of the space travellers must be maintained. Therefore, reliable prevention and countermeasures are needed. read more