Outer space can be hard on the eyes. Exposure to radiation, intense and ultraviolet light, and low gravity cause blood to rise into the head. Because of this, 34 percent of astronauts experience some kind of vision change while in space. Testing vision while in flight, however, can be a challenge. Systems that test sight, to include peripheral vision, are bulky, making them impractical for space travel. "Most of these devices are actually at an ophthalmologist's office," said Wolfgang Fink, Ph.D., founder of the University of Arizona Visual and Autonomous Exploration Systems Research Laboratory. "So, in other words, they are not portable. One cannot self administer them."