Presbyopia

What Is It?

As we age, the lens of the eye becomes increasingly inflexible, making it increasingly harder to focus clearly on near objects. This is called presbyopia. No one knows exactly what causes the lens to become inflexible, but it happens to everyone as a natural part of aging.

In order for us to see images clearly, light rays enter the eye, where the lens bends and focuses the rays on the retina. The lens changes shape to allow the eye to focus on objects at different distances. Beginning early in life - perhaps as early as age 10 - our lenses gradually stiffen and begin to lose the ability to change shape. By the time we are in our 40s, the lens has trouble focusing on close objects, and we begin to experience blurred vision when we try to do tasks that require up-close focus, such as reading or needlework. The lens continues to stiffen until about age 65, when nearly all its flexibility has been lost.

Presbyopia eventually affects everyone, even people who are already farsighted (hyperopic) or nearsighted (myopic). Because people who are farsighted already have difficulty focusing on near objects, they may experience presbyopia a little earlier in life. People who are nearsighted may find that their distance vision improves slightly, and may experience presbyopia a few years later in life.

Symptoms

Presbyopia causes the following symptoms:

• Words appear blurred at a reading distance that used to be comfortable.

• Reading material or other objects must be held farther away from your eyes to gain clarity or see details.

• Brighter light is needed to see clearly (bright light constricts the pupils, which changes the focus of the light on the retina).

• You have difficulty reading late at night, or when you are tired or stressed.

• Your eyes become uncomfortable, or you become tired or drowsy when doing close work because of the strain of eye muscles working to change the lens shape.

• You may have headaches as a result of muscle tension.