Bifocals, eyeglasses with two distinct optical powers, are most commonly prescribed to people with presbyopia (a progressively diminished ability to focus on near objects) who also require a correction for myopia (nearsighted or shortsighted), hyperopia (farsighted or longsighted), and/or astigmatism.
Benjamin Franklin is generally credited with the invention of bifocals.
Bifocals in Atlantis
Bifocals were eyeglasses whose corrective lenses each contain regions with two distinct optical powers. They were invented in the 18th century by Custis Cawthorne, who later became a founding father of the United States of Atlantis.