Is there any change in the vision of Gemini 5 astronauts?

The visual system is the most critical of all sensory systems that face and adapt to space life and work.

Interest in spatial visual ability arises from knowing that the visual environment of space may be different. First of all, the brightness of an object in direct sunlight is higher, because the earth's atmosphere absorbs at least 15% of visible light, which can be greatly improved by water vapor, smoke and clouds. Generally speaking, this means that the lighting level of astronauts during the day is about 1/4 higher than the ground. Secondly, there is no atmosphere and light scattering on the surface like the moon, which leads to darkness in the area without direct sunlight. It is necessary to rearrange the normal visual and sensory relationship. In early aviation missions, the extent to which these environmental differences may interact with subtle physiological changes in the sensory receptor system is still unknown.

The Visibility Laboratory of Scripps Oceanographic Institute in the United States obtained the vision tests of Gemini 5 astronauts before, during and after the flight. The measurement is carried out using the flying vision tester, which is a small automatic binocular optical device with high contrast and low contrast right-angle transmission array. Astronauts judge the orientation of each right angle and punch holes in the record card to explain their reactions.

The second part of Gemini -5' s vision measurement plan is to display large rectangular patterns on the ground in Texas and Australia. The astronaut's task is to report the position of the right angle. In the time between two passes, the display is changed by correcting the orientation, and the size is adjusted according to the expected tilt range, the rising degree of the sun and the vision of the astronauts when they passed before.

The results of the measurement plan on the Gemini 5 spacecraft show that the astronauts' eyesight has neither decreased nor improved during the eight-day mission. Only one flight test was successful, because the meteorological environment greatly hindered the observation of ground graphics. These results confirm that the astronauts' vision is within the range predicted by pre-flight vision measurement.