As stated by some forum members earlier, glasses actually date back to the 13th century, and are not really an advanced technology like some people think. Many medieval myths and stories include people who wore some type of eye glass. They do not even have to look like todays usual eye glasses, just a simple design like these which date back to the 1400's-
the second link actually dates back to around 1350.-http://en.wikipedia.org/wiki/File:Conrad_von_Soest,_%27Brillenapostel%27_(1403).jpg
Heres another:
http://en.wikipedia.org/wiki/File:Hugh_specs.jpg