Myopic Americans: Nearsightedness Rising in U.S.

Myopia appears to have become 66 percent more common in the U.S. between the early 1970s and early 2000s, according to a recent study in the Archives of Ophthalmology.

Vision tests in the 1970s found that about 25 percent of Americans were nearsighted at the time, while similar examinations three decades later found a 42 percent incidence of myopia.

The reason for the uptick in nearsightedness isn't well understood, but some research pegs "excessive amounts of near work, the kind of tasks that require peering at written words or small objects," as a key culprit, according to ScienceNews. But genetic factors are another potential cause. "It might be that somehow the population has changed and that there are more people floating around that have more genetic risk," says one of the study's authors.