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Progressive Lenses That Teach the Eye to See a Different Way

Progressive lenses are a common replacement for bifocal or trifocal lens types. Rather than featuring a sharp dividing line between areas of a lens with different corrective prescriptions, the progressive lens leads the eye through a progression of focal lengths and prescription strengths. The progressive lens helps the eye focus at different distances as the muscles in the eye begin to lose flexibility with age.

  1. How the Eye Works

    • An eyeball includes a lens that works much like a camera's lens. To focus light rays into a clear image, the lens has to adjust its position in the eyeball, and focus the light rays on an area at the back of the eye, called the retina. The lens is held in place by tiny muscles, and the brain controls these muscles so that the eye sees object clearly.

    Loss of Resiliency

    • As a human body ages, the muscles holding the eye lens begin to lose resiliency, as does the lens itself. While this process starts as soon as a child enters school, the most significant rate of decline begins around 40 years of age. As these muscles lose their flexibility, they can no longer move the eye lens through the needed range of motion. As a result, the eye can no longer focus clearly at near distances while still seeing clearly at longer distances.

    Vision Correction

    • Vision corrective progressive lenses "train" the eye. Without lenses, the eye muscles stretch and relax as they adjust the position of the eye lens. With a progressive lens, the eye lens muscles "learn" that they do not need to work to focus on some objects. The eyes become retrained, and depend on the lenses. As a result, in older adults a person's natural vision quality may even decrease after using progressive eyeglasses over a short time.

    Training an Eye

    • For younger children, the process can be used in reverse. In the case of children's eyes, which are fully formed yet not accustomed to focusing, progressive lenses can be designed to activate and encourage eye muscle use. This process requires a number of prescriptions, which meet the child's initial eyesight needs, and then use a custom progressive lens that encourages the child to develop the eye muscles. As the child's eye muscles strengthen, his eyes are trained to function better. The lenses work to improve the patient's ability to focus eye muscles on objects at different distances.

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