Space Travel Affects Eyesight

A study by NASA reveals that astronauts who spend around six months in Space and hence exposure to micro activity may become victims of Poor Eyesight. The structures in the back of their eyes may change causing their vision to blur.

"In astronauts over age 40, like non-astronauts of the same age, the eye's lens may have lost some of its ability to change focus," said study co-author Dr. Thomas Mader, an ophthalmologist (a specialist in medical and surgical eye problems) with Alaska Native Medical Center, in a journal news release. "In the space program's early days, most astronauts were younger, military test pilots who had excellent vision. Today's astronauts tend to be in their 40s or older. This may be one reason we've seen an uptick in vision problems. Also, we suspect many of the younger astronauts were more likely to 'tough out' any problems they experienced, rather than reporting them." 

References [1] Medline Plus [2]Wikipedia