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Bifocals and Multifocals: How They Work

Bifocals and Multifocals Hendesronville

People with refractive vision errors, also known as presbyopia (age-related decline in near vision), have special needs when it comes to eyesight. As you age, your distant or far vision may only require slight adjustments to your prescription; however, your close-up or near vision will usually require a higher-powered lens. A sign of refractive vision issues is a need to read materials at a distance—usually at arm’s length.

The solution for most people is bifocal or multifocal lenses. Both versions are found in soft materials or rigid gas permeable (RGP) contacts. RGP lenses can last several years and are a good choice for people with astigmatism. Soft lenses are easier to get used to but must be replaced weekly, monthly, or quarterly. They’re also available in a disposable design; however, this can be more expensive.

 

Bifocal vs. Multifocal 

Most people have heard the word “bifocal” and understand what it means. “Bi” denotes two, and “focal” specifies the prescription type of the lens. A bifocal contact has two separate prescriptions, usually divided between the top and bottom half of the lens. Multifocal is more of a blanket term. It encompasses any lens that utilizes two or more prescriptions. All bifocal contacts are multifocal, but multifocal lenses aren’t necessarily bifocals.

 

How Multifocal Contacts Work

Lenses work differently depending on how they’re made. There are two main types of multifocal contact lenses: alternating vision and simultaneous.

Alternating vision multifocals are also known as translating lenses. Your pupil alternates between the powers as your gaze shifts. This setup is common in older glasses, which you can identify by the line across the lower portion.

Simultaneous lenses force your vision through both powers in unison. Your eyes adapt and choose the correct power to match the situation. Simultaneous lenses are available in concentric ring and aspheric designs. In concentric lenses, rings of near and far powers are alternated. Aspheric styles start with one power in the center and transition gradually to the outside.

 

Are Multifocals Right for Me?

Multifocal lenses have been used in glasses for years, but they weren’t popular in contacts until recently. New technology has created more comfortable and efficient multifocal contact lens designs. Plus, you can choose the lens style that works best for you. If you have refractive vision or presbyopia, chances are that there’s an option available that will fit your lifestyle and let you see more clearly.

 

For additional questions, contact Judd Family Eyecare.