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Progressive Lenses

Invisible Line Progressive Lenses

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Updated March 05, 2010

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Progressive lenses, often referred to as no-line bifocals, are used in eyeglasses to correct presbyopia. At around 40 years of age, most people begin to experience presbyopia, or the loss of the eye’s ability to change focus to see near objects clearly. Progressive lenses make it possible to see clearly at all distances.

What Are Progressive Lenses?

When presbyopia begins to affect your vision, you will need a bifocal.

Bifocal lenses contain portions for near and distance vision, separated by a distinct line. Bifocals bring your vision into focus when looking at a far distance and bring your near vision into focus when viewing close objects, without having to take your glasses on or off.

Progressive lenses contain different viewing portions, just like a bifocal, but they have no visible lines to separate them. Instead, progressive lenses have a smooth graduation of different lens powers.

Advantages of Progressive Lenses

Progressive lenses provide the most natural vision possible. With progressive lenses, reading power gradually increases as you look down the lens. Because of this, not only do you have clear distance and near vision, but clear intermediate vision as well.

A progressive lens is the lens of choice for the best cosmetic appearance. There is no demarcation line in a progressive lens, so the lens looks just like a single vision lens. Many mature people enjoy this feature because it gives a more youthful appearance.

Adjusting to Progressive Lenses

Progressive lenses usually require a little time to get used to.

If you are prescribed progressive lenses for close-range tasks, you will be taught to face your visual task directly and utilize the bottom-center of your lenses. You can accomplish this by raising your chin slightly while you read and/or moving your reading material down and closer to your body. When walking, if you need to look at the ground, lower your chin and look through the upper half of the lens.

Because of the invisible, seamless change in power of a progressive lens, most progressive lenses have small wavy zones in the lower right and left sides. During the first days of wearing progressive lenses, expect to be somewhat aware of these wavy zones, especially with rapid head movements from side-to-side.

After a few days of full-time wear, however, these wavy zones will disappear or become much less obvious. It is rare to fully adjust to progressive lenses in the first few days. Some people adapt very quickly, while others may take a few weeks.

Source:

Dowaliby, Margaret. "Practical Aspects of Ophthalmic Optics." Professional Press Books, 1988.

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