1 : having two foci 2 : pertaining to the compound spectacle, which contains a smaller lens for near vision placed below the center of the larger lens, which is for distant vision 3 : bifocal glasses
Lenses of eyeglasses that have two distinct areas of focus The prescription in the top portion helps to see distant objects while the prescription in the bottom portion of the lens helps to see near objects There are many styles of bifocals, such as flat tops, progressive and even double bifocals
The simplest type of lens that gives the wearer more than one focal length --- two The top of the lens provides clear vision at distance (infinity) and the bottom "reading add" (or "segment") gives you clear vision at a reading distance For some people we make bifocals that have focal lengths other than infinity and reading distance, but not often
a lens that is designed with two different prescription areas to correct for both near and distance vision