Bifocal Contact Lenses

Solution to "Shrinking Arms"

Bifocal contact lenses are designed to correct vision for those of us suffering from that curious condition of "shrinking arms," aka. presbyopia.

As you age, the lens within your eye (behind your iris) becomes less and less flexible. As a result it's increasingly difficult to focus on nearby objects. Many of us will find our distance vision remains the same (either no correction is needed, or current correction is sufficient) while our near vision becomes blurry. Bifocal contact lenses can correct this unwanted situation by correcting both near and distance vision at the same time.

Until recently your options were quite limited when it came to choosing bifocal contacts. However recent advancements in technology have resulted in nearly all types of lenses being available in the bifocal variety. Bifocal lens wearers can now choose from daily disposable lenses, frequent replacement contact lenses, or extended wear contact lenses, as well as conventional contacts (vial) or RGP bifocal contact lenses.

How do bifocal contact lenses work? Bifocal contact lenses work in essentially the same way as bifocal eyeglasses: each lens has two powers - one for near vision correction and the other for distance correction. Manufacturers accomplish this in a number of different ways:

Aspheric design

With aspheric design, there is a graduated change in the power of the lens, such that the difference between near and distance correction is not as obvious. Both the near and distance corrections are within the pupil area, and your eye learns to differentiate which part to use for each distance.

Concentric design

With concentric design, there is an obvious difference between distance and near corrections, with one being in the center of the lens and the other at the periphery. Again, your eye will adapt to determine which part of the lens to use in order to see clearly.

Translating design

Translating design is similar to bifocal eyeglass design, in that distance correction is located above near correction - a line separates the two. While this lens is not symmetrical all the way around, it must not rotate on the eye; therefore, the lens is modified to prevent it from moving.

Bifocal Contact Lens Articles