Bifocal - One Lens two functions, distance and near
Buying a pair of glasses can be a daunting experience. There are so many styles of frame to choose from and all too often little consideration is given to the lenses. Remember when buying new glasses, your choice of lens can have a major impact on your quality of vision and the overall look of your glasses. Here we explain some of the different lens options available.
A bifocal is used when 2 prescriptions are needed, usually for long distance and near vision ie: close reading.
Both prescriptions are put on to the same lens, with a visible line separating them.
This is a more convenient option, as there is no need for 2 single pairs of glasses.
Although, these can cause some problems with mid distance tasks such as a computer, so depending on the person's age and tasks required, a middle distance/reading bifocal can be used.
The picture shows a bifocal lens. Notice how the closer detail on the mobile phone is in focus, and the window is in focus in the background, but the flowers in the mid distance are still out of focus. A varifocal lens would help you focus on objects at all distances.