Bifocals

Bifocals are glasses that have two different strengths of lenses depending on where you look in the lens. Typically bifocals for presbyopia and myopia have the lower section 1-2 diopters weaker than the upper section, for use during reading.

The EM method uses separate differentials and normalized lenses rather than bifocals, making it easier to adjust your lens selections one at a time.

See Also

• Multifocal