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Last update: June 2003

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The EyeCare Connection

abstracts and answers to commonly asked questions

Presbyopia

Prez-bye-OH peeah (From the Latin: old sight)

What is Presbyopia?

The need for a vision correction for near vision tasks occurs for most people around age forty. Often it is referred to as one of the inevitable aspects of the aging process. It doesn't matter if you require a correction for distance, if you are nears ighted or farsighted. Considered a normal part of the aging process, the crystalline lens, located inside your eye and just behind the pupil, is responsible for adjusting the focus from a distance point to a near point. Tiny cilliary muscles pull and push on the lens altering it's curvature, thereby changing it's focal power. As we age, the lens becomes larger, less flexible and the cilliary muscle itself may become less powerful. This is a slow process, starting during the third decade of life and becoming symptomatic for most people by age 45. The most commonly reported symptoms are "my arms aren't long enough anymore" or "I can see fine far away but it takes a lot of effort to see small print these days, and I need more light"
 
 

What causes Presbyopia?

Located a few millimeters inside your eye, just behind the iris (the colored part) and the pupil (the opening in the center of the iris) is the crystalline lens. The lens is designed to constantly adjust it's focal power in order to bring near objects into view. As we age, our crystalline lens becomes larger, less flexible and more rigid. The muscles that pull and push the lens into the appropriate shape to yield a proper focus fatigue. They are less able to exert force on the lens as it enlarges and the fibers that connect to it become slack . The focusing system then fails to perform it's role in the vision system. This is the currently accepted rationale of the causative role resulting in the condition called presbyopia.  

A closely related aging event is the clouding of the crystalline lens, called cataracts. Please see the Abstracts: Cataracts or EyeCare Report: The Aging Eye, for more info.
 
 

Treatment of Presbyopia

The traditional approach is simply to use near or reading glasses. If you need prescription lenses for distance as well, bifocal lenses may be in order. Near eyeglasses provide the degree of focusing no longer provided by your crystalline lens. There are also multifocal contact lenses and monovision contact lenses. Exercising the cilliary muscle is sometimes helpful, especially in early presbyopia and nutritional issues may play a role, too. A guide the exercises are included in the EyeCare Report: The Aging Eye.

Surgical adjustment to "tighten" the lens-cilliary muscle attachments are under investigation and are being done clinically. The surgery does show promise in restoring limited focusing ability. The effect does not appear to last for more than a few years and many doctors feel the risks do not outweigh the benefit. As more data on clinical trials become available, this page will be updated to reflect the new information.

See also the Abstract: Spectacle Lenses and for contact lens information, see the EyeCare Report: Contact Lenses.