What contribution did the famous American politician B. Franklin make to medicine?

Benjamin Franklin is a famous American politician, scientist, inventor, journalist, writer, freemason. He is considered one of the founding fathers of the United States as a state. In particular, he is considered the author of the US Constitution. Born on January 17, 1706 in Boston, in the family of an English immigrant. He died on April 17, 1790 in Philadelphia. His contribution to medicine is considered to be the authorship of bifocals. According to legend, he was tired of constantly changing glasses for myopia (if necessary to look into the distance), for glasses for hyperopia (if it was necessary to read). He simply sawed through the lenses in both glasses, and inserted half of each lens into one frame for each eye. Later, such lenses were made from a whole plate.