Difference between revisions of Bifocals

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

The EM method uses separate [[differentials]] and [[normalized]] lenses rather than bifocals, making it easier to adjust your [[lens selections]] separately.