The importance of bifocals in today's society
When and whom the bifocals were invented by
Ben Franklin's invention comes to life
Advantages and Disadvantages of Ben Franklin's invention- Bifocals
Disadvantages were based on the way they were manufactured back then. Since it was two lenses " stitched" together, they easily got dust within the two lenses, and also the lens itself was heavier. Also, the lenses themselves were held together by something called eye wire, which came apart very easily.
Association, I. H. (n.d.). Benjamin Franklin’s Inventions. Retrieved 11 March 2015, from http://www.ushistory.org/franklin/info/inventions.htm
Eyeglasses and Contact Lenses. (n.d.). Retrieved 11 March 2015, from http://www.stanfordchildrens.org/en/topic/default?id=eyeglasses-and-contact-lenses-90-P02089
Museum of Vision: Exhibitions. (n.d.). Retrieved 11 March 2015, from http://www.museumofvision.org/exhibitions/?key=44