Today bifocal lenses are practically obsolete. Benjamin Franklyn invented these lenses in 1784. Bifocals have only 2 focal lengths. These obviously pale in comparison to progressive lenses, also known as mulitfocals, which have every focal length from reading, to infinity. The bifocal lens design is also useless for computer use. If you are still wearing bifocal lenses come in and talk to us about your options.