For adults, bifocal or progressive addition lenses provide the convenience of not having to carry around two pairs of glasses. For children it is more than a matter of convenience. Children must make rapid changes in looking from the desk to the blackboard and back again, and two separate pairs of glasses would be impractical. A single vision distance prescription may be inappropriate for near visual activities. A bifocal prescription may serve to limit the progression of nearsightedness, or to assist binocular vision when reading.
Bifocal lenses are actually a form of vision therapy.
They are used for a period of time and when they have served their purpose they may no longer be needed. In some instances bifocals serve a maintenance function similar to the way a dental retainer helps preserve the improvement made on a child's teeth. Wearing a bifocal prescription will not create a dependency on the need for this type of lens. It is also helpful to know that children adjust to wearing bifocals quite easily. Bifocal lenses for children are available in polycarbonate material, which is an important safety factor.