Bifocals are eyeglasses with two distinct optical powers. Bifocals are most commonly prescribed to people with presbyopia who also require a correction for myopia, hypermetropia, and/or astigmatism.
Benjamin Franklin is usually credited with the creation of the first pair of bifocals in the early 1760s, though the first indication of this comes from a political cartoon printed in 1764. A great number of letters and publications from that time period refer to Dr. Franklin's spectacles, including his first reference to them in a letter dated July 22,1785.

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