About the Eyes

The most common vision disorders are astigmatism, hyperopia (farsightedness), myopia (nearsightedness) and presbyopia. Astigmatism, hyperopia and nearsightedness are also known as refractive errors. All are correctable with lens (contacts or eyeglasses) or LASIK surgery.

Astigmatism: Astigmatism comes from the root words "A" meaning without and STIMGA meaning point. In the astigmatic eye, a point of light is unable to focus sharply due to the oval "football" shape of the cornea (the front surface of the eye). Light rays entering the vertical (north-south) curve of the cornea may focus on the back of the eye, but ray entering the horizontal axis (east-west) may not. This causes a blur at both distance and near.

Hyperopia: In the farsighted eye, light that should focus on the retina (the back of the eye) instead focus behind the retina. People with hyperopia compensate by using muscles in the eye which can lead to eyestrain, fatigue and even headaches. Close-up work such as reading or computer use may be especially uncomfortable. Children with hyperopia often pass school vision screenings by unnaturally focusing their eyes. This may lead to poor reading abilities and can only be detected by a complete vision exam.

Myopia: In the nearsighted eye, light that should focus on the retina instead focuses before it gets to the back of the eye. Either the cornea or the lens of the eye is too curved or long. Either way, distance vision is blurred, but close-up vision is generally good. Again, early and regular eye exams are important for children to detect this problem.

Presbyopia: At about age 40, the lens of the eye loses some of its ability to focus "near objects" due to less flexibility of the lens fibers and the muscles that control the lens. This condition is known as presbyopia. Because presbyopia involves the lens, it is different from refractive errors which involve the shape of the cornea.

In the beginning only the fine print becomes blurred. But over time, even larger print and objects at increasingly farther distances become difficult to see. Your Today's Vision doctor may recommend bifocal eyeglasses, progressive (invisible line) eyeglasses, rigid gas permeable contact lenses or soft contact lenses. With contacts, your doctor may advise using the "monovision" technique in which one eye is corrected for near, the other to see far - or bifocal or progressive contacts in either the rigid or soft lens design.

If the patient can tolerate monovision contacts, this can sometimes be simulated in LASIK surgery, also.

Check out Anatomy, Refractive Errors, FAQ (Frequently Asked Questions) and Optical Definitions to learn more About the Eyes.

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At about age 40, the lens of the eye loses some of its ability to focus close due to less flexibility of the lens fibers and the muscles that control the lens. This condition is known as presbyopia. Because presbyopia involves the lens, it is different from refractive errors which involve the shape of the cornea.

In the beginning only the fine print becomes blurred. But over time, even larger print and objects at increasingly farther distances become difficult to see. Your Today's Vision doctor may recommend bifocal eyeglasses, progressive (invisible line) eyeglasses, rigid gas permeable contact lenses or soft contact lenses. With contacts, your doctor may advise using the "monovision" technique in which one eye is corrected for near, the other to see far - or bifocal or progressive contacts in either the rigid or soft lens design.

If the patient can tolerate monovision contacts, this can sometimes be simulated in LASIK surgery, too.