Bifocals - History of Bifocals
As best as people know, the inventor of bifocals was Benjamin Franklin, the American statesman. This most likely happened in the 1760s or early 1770s. Bifocals are glasses meant for people that have difficulty focusing on both near and far objects. The top half of each lens is for seeing distance, and the lower half is for reading.
Benjamin Franklin required glasses for most of his life, and began to need reading glasses to see close objects as he got older. He got tired of switching back and forth between two types of glasses, and came up with a simple way to solve the problem. He had the lenses for his up-close and distance glasses cut in half, and placed in the frame together. The distance halves were on top, and the up-close halves in the bottom.
- The lens of the human eye is usually flexible, which allows the focal distance to change. As people age, the lenses of their eyes harden. Bifocals help by providing two different focal distances.
- Benjamin Franklin called his glasses "double spectacles". The word "bifocals" was created at the same time as the word "trifocals". John Isaac Hawkins invented trifocals, glasses meant to focus on three different distances, in 1824. Though he gave the glasses their name, he credited Benjamin Franklin for inventing the bifocals.
- For many years, bifocals were the same style as Dr. Franklin's. The rim for each eye contained two pieces of glass, which made them fragile. Fusing the lenses together made them stronger. A method to do this was developed by Louis de Wecker, and patented by Dr. John L. Borsch, Jr. in 1908.