Bifocal eyeglasses, also called bifocal spectacles, are some of the most widely used glasses among people who have presbyopia and other nearsighted vision problems at the same time. However, many people still do not know who has invented bifocal spectacles. And even for those who know something, they are still uncertain about the answer. Benjamin Franklin is only legally and universally recognized inventor, though many data has it that other people may be the first creators of bifocal spectacles.
It matter little what the reality is, but the story about Franklin and Benjamin Franklin is really very interesting. Here is the bifocal glasses history.
Compared to other glasses, bifocal spectacles are much younger with a very short history, less than two and a half century up to now. They do not come into being till 1784 when Benjamin Franklin spends more time in reading. As one of the most respectable state men in the history of US, Benjamin Franklin has also made many achievements in other fields. Of which, Bifocal spectacles are very typical. During that time, he becomes older and gradually looses his vision, just because of presbypia and other eye problems probably. He has to replace the glasses for farsighted vision when he wants to look afar; and he has also to replace glasses for nearby vision when he reads. This is very boring and inconvenient. Therefore, he wants to change such situation- whether the two lenses, one most convex lens and another least convex lens, can be placed into the same frame. As one of the most creative men in the world, Franklin has found the best way and embedded the two lenses in the same frame successfully. With the new glasses, he thinks now that there are two different focuses on each lens, they should be called bifocal spectacles.
However, the first bifocal eyeglasses invented by Benjamin Franklin are totally different from what people can now see. Generally, for each pair of glasses, there are four lenses. That’s to say, he has used two wholesome lenses on each side of the frame for one eye. Therefore, it can easily explain why the early bifocal spectacles are very heavy to wear and funny to see. And such situation dose not change until the 20th century when more people have to wear glasses and great achievements are scored in the industry. Those modern bifocal eyeglasses are combined by two half-cut lenses. And now, more and more innovations are made in bifocal glasses. This is what Benjamin Franklin has never thought of.