We all know about TruFocals and PixelOptics, NASA is testing the above two types of adjustable bifocal lenses during training, and possibly will choose one to be used on the mission to the space.

Just like any other people over 40s, most of the astronauts who are sent to the space are over 40, therefore they also develop vision problem called presbyopia, not to say that more other non-astronaut people such as scientists and even tourists will be sent to the space. So the demand of bifocal lenses are pretty high in the space. Before NASA considers to use TruFocals and PixelOptics’ adjustable lenses, people in the space used to wear normal bifocals and progressive lenses if they have additional vision error other that presbyopia. Experiences show these types of eyeglasses do not fulfill a successful job in offering vision correction in the space environment and in heavy space gear. In addition, the vision of the people in the space will suffer degeneration thanks to microgravity. In this case, the original bifocals with fixed lenses could not address the further vision problems that have deteriorated recently during the space mission. Under these circumstances, it seems the only choice is to resort to lenses like TruFocals which are fully adjustable within some range.

NASA’s primary interest in adjustable eyeglasses has been as a replacement for the normal reading glasses, bifocals or progressive lenses that astronauts take with them into space. The small corrective zone on these conventional eyeglasses is fine for the normal reading posture (with the eyes looking through the lower portion of the lens) but is much less helpful when monitoring overhead readouts, for example. The agency is also studying the long-term effects of time spent in microgravity, which causes bodily fluids to gravitate to the upper body and has been known to cause degradation of vision in some astronauts. Once more is understood about how prolonged space travel affects vision and why, NASA will be in a better position to address the problem, either with the help of adjustable-lens glasses or some other means, according to Gibson.

If the test goes on smoothly, NASA will soon annouce which lenses will be deployed for astronauts and other space people who may need presbyopic correction.

Source: Optical News