BIFOCAL LENSES:

Bifocal lenses
BIFOCAL LENSES:

Designed to correct two distances, usually one for distance and one for near. The separation of the distance and near zone is visible as shown in the chart. Used especially by people with presbyopia (age-related eyestrain).

The two most common types of bifocals are: Flat Top and Invisible:

 

Bifocal Flat Top: The segment designed to correct near vision is crescent-shaped. The distance and near segments are separated by a visible line.

 

 

Invisible Bifocal: the distance and near segments are separated by a line that is not visible. The dividing line is polished in such a way that it is not visible. Vision in the area where the two segments meet may be slightly blurred, causing some difficulty in adaptation.