Farsightedness



Farsightedness is an eye disorder that causes objects that are close to a person to appear out of focus or blurry, while objects at a distance may seem clear.

KEYWORDS

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Hyperopia

Ophthalmology

Optometry

Vision

To people with farsightedness, the words on this page would seem blurry, unless they were wearing prescription (pre-SKRIP-shun) eyeglasses or contact lenses designed to correct the problem. But if they looked up from the page to read a sign across the room, they probably could read it easily.

What Is Farsightedness?

In most cases, farsightedness occurs when the eyeball is shorter than normal. For an object to appear clear, the light passing through the eye must focus on the retina, a layer of photosensitive * cells on the back of the eye. The retina is something like the film in a camera. It is where the image passing through the eye is projected and then sent along the optic nerve * to the brain. In the brain, the image is "developed" into what we see. If the eyeball is too short, the image that is projected onto the retina by close objects is blurred, and the person is said to be farsighted.

People with farsightedness usually have the disorder from birth. It is probably inherited from parents, although just because a parent is farsighted does not mean the child necessarily will develop the problem too. Babies and younger children often are able to adapt to the problem. Muscles around the eyeball can change its shape, which makes it longer and allows the image to be focused properly on the retina. But as a child gets older, the muscles cannot do as good a job changing the eyeball's shape, and images close up are out of focus.

How Do Doctors Diagnose and Treat Farsightedness?

It can take many years for the symptoms of farsightedness to become noticeable. Eventually, people with farsightedness notice problems while reading or seeing objects that are close, whereas things that are farther away remain clear. They also may start to get headaches after reading or doing other close work, and they may feel as if their eyes are tired.

Ophthalmologists * can diagnose farsightedness and correct it easily with prescription eyeglasses or contact lenses. These change the focus of the images passing into the eye so they are projected properly onto the retina. Surgery to correct the problem is available, but it is not as widely used as surgery to correct nearsightedness.

* photosensitive means responsive to light.

* optic nerve is the nerve that sends messages, or conducts impulses, from the eye to the brain, making it possible to see. The optic nerve is also referred to as the second cranial nerve.

* ophthalmologist (off-thal-MOLL-o-jist) is a medical doctor who specializes in treating diseases of the eye.

Presbyopia

Many people become more farsighted as they age. They develop a condition known as presbyopia (pres-be-O-pe-a), which is

Anatomy of the eye. If the eyeball is too short, an object held close to the eye appears to blur as its image is projected onto the retina.
Anatomy of the eye. If the eyeball is too short, an object held close to the eye appears to blur as its image is projected onto the retina.
Latin for "old eyes," that causes close objects to appear out of focus. Presbyopia results because the lens at the front of the eyeball becomes thicker and less flexible as a person ages. This causes the eye to have trouble clearly focusing the images passing through the lens. The first sign of presbyopia may be noticed when adults pass age 40. They start to find they cannot read the newspaper as well. It is one reason one hears people joke that their arms are too short, because they try holding the paper or book farther away so they can see it clearly. People with farsightedness may need stronger prescription eyeglasses once they pass age 40. People with nearsightedness may need bifocal * or multifocal lenses.

* bifocal or multifocal (progressive) lenses are prescription eyeglasses that have lenses divided into two or more sections. The bottom section allows a person to see things clearly that are close, and the top section allows a person to see things clearly that are far away.

See also
Nearsightedness
Presbyopia

Resources

The U.S. National Eye Institute posts a resource list of eye health-related publications and organizations at its website.
http://www.nei.nih.gov/publications/sel-org.htm

American Academy of Ophthalmology, P.O. Box 67424, San Francisco, CA 94120-7424. The American Academy of Ophthalmology website includes a search engine that locates information about many disorders of the eye.
Telephone 415-561-8500
http://www.eyenet.org

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