Well all items thats will make NPC more unique will be good: eye-patches, masks, circlets and other include Glasses can be done if not by Devs then modders, besides thats not modern ones and Glasses have long history
The first eye glasses (spectacles) appeared around 1286. By the 14th century they were available across north-west Europe.
The glasses were formed from two convex shaped glass/crystal stones, each surrounded by a frame with handle. The handles were then connected together by a rivet. Production started in Florence then the Low Countries. Manufacture in England began in the 15th century. Artisans, glassmakers, jewelers, clockmakers, monks and scientists all helped refine their development. More
The original inventor is unknown but early eye glasses were made by adapting an earlier invention, - the glass stone magnifier, essentially by joined two of these together. They were first developed in Pisa, Italy. The earliest reference is in a sermon by a monk called Giordano (Feb.23, 1306), he said: "It is not yet twenty years since there was found the art of making eyeglasses which make for good vision. By the time the printing press was invesnted (around 1450), glasses were already used by artisans, monks and other religious scholars. Once books became more widely available the demand for eye glasses rose dramatically. By the end of the 15th century, spectacle peddlers (street sellers) were a common sight in Western Europe.
http://www.ireference.ca/search/glasses/
http://news.bbc.co.uk/media/images/47140000/jpg/_47140052_08.jpg
http://cookit.e2bn.org/library/1256977031/98880_edited1.original.jpg
http://blog.aurorahistoryboutique.com/images/medieval-glasses.png