Bifocal glasses are designed with 2 different lenses in the one pair of glasses. They are generally used by people who have diminished eyesight and also require correction for nearsightedness. This allows the wearer to see clearly at all times, while also providing focus for tasks such as reading. Traditionally they were made of two separate lenses, but today a small section for reading is molded into the main lens.
Who invented bifocal glasses?
Although there has been some debate about the inventor of this type of glasses, the invention is generally credited to Benjamin Franklin. No one knows when he invented the first pair of bifocal glasses, but recent evidence suggests that it could have been earlier than most historians once believed.
He visited France on a diplomatic mission between 1777 and 1785. In 1779, evidence suggests that he ordered a special pair of spectacles from an English optician, which is now believed to be a pair of bifocal glasses. However, there is some evidence to suggest that he could have been wearing bifocal glasses much earlier. A newspaper editor, named John Fenno, met with an elderly Franklin who told him that he had been wearing bifocals for 50 years.
The term bifocals didn’t originate until 1824 when John Isaac Hawkins invented trifocal glasses. He named Benjamin Franklin’s lenses bifocal.