Perhaps you had idly noticed that a lot of people need glasses these days. Maybe some of you have even wondered what we all did before glasses were invented. A few of those might have even considered the possibility that we didn't need glasses, as a people, until recently.

According to a 1995 Cornell University study, "Nearsightedness now affects from 20 percent of some populations to 80 percent of others in the United States and Europe, and up to 90 percent in Far East countries."

There are two prevailing theories for this:

  • Environmental: all the "near work" we do in modern society (reading, computers, time spent inside buildings, etc) has adverse effects on eye development.
  • Genetic: corrective lenses, which conclusively date back approximately 700 years, have kicked the natural selection-driven evolution process into reverse for eyesight, and 20/20 vision happened to be a recessive trait.