- Types of Corrective Lenses -
Single vision lenses provide correction with only one focal point.
Standard bifocals have a visible line and provide two fields of vision, distance and near. There is no special area for midrange viewing
These lenses have 2 lines and provide three fields of view; distance, intermediate, and near.
Progressive addition lenses have no lines and provide a continuous, gradual change in power from eyelevel down to the bottom of the frame.