Bifocal Contacts Multifocal Contacts

What are Bifocal Contacts &  Multifocal contact lenses

Bifocal contacts lenses have two prescriptions in the same lenses. Multifocal contact lenses have a range of powers (similar to progressive spectacle lenses) in each lenses. "Multifocal" is also used as a catch-all term for all lenses with more than one power, including bifocals.

How Multifocal Contact lenses Work

Bifocal and multifocal contact lenses work in several different ways, depending on the design of the lenses. The designs fall into two basic groups:

1. Translating lenses (or "alternating vision" lenses) are so named because your pupil alternates between the two powers, as your gaze shifts upward or downward.
    
2. Simultaneous vision lenses require your eye to be looking through both distance and near powers at the same time. Although this might sound unworkable, your visual system learns to select the correct power choice depending on how close or far you're trying to see. Simultaneous vision lenses come in two types:

• Concentric ring designs
• Aspheric designs

Bifocal Contact lenses

Translating bifocals work much like bifocal eyeglasses. They have two power segments, with an obvious line of separation between the distance correction on top and the near correction below. Your pupil looks through either one or the other, depending on whether you're looking far or near.
With bifocal eyeglasses, this mechanism works because the lenses stay in place even as your eye moves. That can happen with contact lenses, too. Since most translating bifocals are GP lenses, they are smaller in diameter than soft lenses,

and they ride on your eye above your lower eyelid. Therefore, when your gaze shifts downward, the lenses stays in place, allowing you to see through the lower, near-correction part of the lenses.

Will Bifocal Contact lenses Work for Me?

Bifocal contact lenses have been around for many years, but until recently they weren't very popular. Older bifocal designs didn't satisfy many people, leading to frustration among wearers and prescribers alike.
Today, new technology has produced more successful designs, as well as a greater variety of designs. So if one design doesn't work for you, another might. Your doctor may also try these related techniques:

• Monovision involves using single-vision lenses to put your near prescription on one eye and your distance prescription on the other [Contacts for monovision].
• Modified monovision uses a single-vision lenses on one eye and a multifocal lenses on the other.