The low levels of gravity (microgravity) in space cause significant changes in astronauts’ eyes and vision after six to 12 months aboard the International Space Station (ISS), according to a study published in the IEEE Open Journal of Engineering in Medicine and Biology. The low levels of gravity (microgravity) in space cause significant changes in astronauts’ eyes and vision after six to 12 months aboard the International Space Station (ISS), according to a study published in the IEEE Open Journal of Engineering in Medicine and Biology. Space Exploration Phys.org – latest science and technology news stories