<P> Bifocals are eyeglasses with two distinct optical powers . Bifocals are commonly prescribed to people with presbyopia who also require a correction for myopia, hyperopia, and / or astigmatism . </P> <P> Benjamin Franklin is generally credited with the invention of bifocals . Historians have produced some evidence to suggest that others may have come before him in the invention; however, a correspondence between George Whatley and John Fenno, editor of The Gazette of the United States, suggested that Franklin had indeed invented bifocals, and perhaps 50 years earlier than had been originally thought . Since many inventions are developed independently by more than one person, it is possible that the invention of bifocals may have been such a case . Nonetheless, Benjamin Franklin was among the first to wear bifocal lenses, and Franklin's letters of correspondence suggest that he invented them independently, regardless of whether he was the first to invent them . </P> <P> John Isaac Hawkins, the inventor of trifocal lenses, coined the term bifocals in 1824 and credited Dr. Franklin . </P>

Who invented the lightning rod and bifocal glasses