Progressive Lenses: How They Work

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What are progressive lenses? Sometimes called "no-line bifocals," progressives eliminate the sharp lines across the lens traditionally associated with bifocals and trifocals and disguise the fact that you are wearing reading glasses.

Truly "multifocal," these no-line lenses also provide a progressive correction of your vision that makes getting used to them easy.

There are no areas of the lens that are exclusively for looking at objects in the distance or exclusively for close work. Progressive correction enables you to move your eyes "just enough" to focus clearly on the objects you wish to see.

A progressive lens offers a vertical corridor of clear vision that runs up and down the lens.

The optometrist or ophthalmologist takes precise measurements of your eyes to place the vertical corridor at just the right location so your eyes can easily access the various powers of the lens for just the right focus at any distance.

This eliminates the major complaint with traditional bifocal and trifocal lenses known as image jump.

With traditional bifocal and trifocal lenses, objects seem to "jump" past your eyes when your gaze passes the sharp boundary between the upper and lower parts of the lens.

With progressives, the transition between lens strengths is seamless, allowing you to change your focus from near to far and back again with ease.

With progressive, you can work at your desk and look up to see across the room without needing to move your eyes up and down. You can see near, far, and intermediate distances equally clearly. And your lenses enhance a youthful appearance.

Progressive used to have to be set in large frames because of all the different strengths required of the lens. New materials, however, have allowed manufacturers to make "short corridor" lenses with compact designs and large zones for close work or reading.

Whereas the choice of frames for progressive lens placement used to be limited, now there are many choices.

Progressives can be made from plastic, glass, polycarbonate, or photochromic materials that darken when you go outdoors. Your optometrist or ophthalmologist is in the best position to help you choose the material for your lens.

Whichever material you choose for the lens, however, progressives usually require a brief period of adjustment. You really need to be aware of this before you drive out the parking lot!

Progressives let you see clearly at all distances directly in front of you, but causes minor distortions of images in the periphery of your vision.

That is, you see well straight ahead and up and down, but you may not see as clearly to your right or left. It is very important that you know before the first time you drive wearing your new glasses.

This right-left distortion can cause you to have a sense of "swimming" the first time you clear traffic. If this happens, just make a slight head movement to look more directly at objects.

This effect, however, usually disappears in a few minutes to a few days, and many wearers of progressive lenses never experience it at all.

Also, if you are naturally farsighted, that is, you were farsighted before reaching age 40, adjusting to progressives may take longer than if you had presbyopia or myopia (nearsightedness). Nearly everyone, however, can wear modern progressive lenses successfully.

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