What Is Nearsightedness?

Is it hard to see highway signs until you’re a few feet away but easy to read a book up close? Chances are you’re nearsighted. Your doctor will call this myopia. Many people see this way. Your eye doctor can fix it with eyeglasses, contacts, or eye surgery.

What Causes It?

The structure of your eye is to blame. When your eyeball is too long or the cornea -- the protective outer layer of your eye -- is too curved, the light that enters your eye won’t focus correctly. Images focus in front of the retina, the light-sensitive part of your eye, instead of directly on the retina. This causes blurred vision. Doctors call this a refractive error.

Symptoms

Chances are the only symptom will be blurred vision at a distance. You may have also noticed:

  • Headaches
  • Squint
  • Eye strain
  • Eye fatigue when you try to see more than a few feet away
  • Nearsighted children often have trouble reading the blackboard at school.

Diagnosis and Treatment

An eye exam can show you if you’re nearsighted. Glasses, contacts, or refractive surgery can correct nearsightedness.

When you have myopia, your prescription for glasses or contact lenses will be a negative number. The more negative the number, the stronger your lenses will be. For example, -3.00 is stronger than -2.50.

Your prescription helps the eye focus light on your retina. That clears up your vision.

Eye surgery can improve your vision so much you may not ever need glasses or contacts again. The most common procedures for nearsightedness are:

  • Photorefractive keratectomy. Also called PRK, this surgery uses a laser to sculpt the middle layer of your cornea. That flattens the cornea’s curve and lets light rays focus closer to or on your retina.
  • LASIK. This the most common surgery for nearsightedness. The surgeon uses a laser or another tool to create a thin flap on the top of your cornea. He surgeon sculpts the cornea with another laser and moves the flap back into place.

Does It Get Better Over Time?

Nearsightedness runs in families and will probably start in childhood. It stops changing after your teenage years, but not always. If you notice changes in your vision, get your eyes checked. See your eye doctor every year.

WebMD Medical Reference Reviewed by Alan Kozarsky, MD on August 08, 2016

Sources

SOURCES:

Yanoff, M; Duker, J. Ophthalmology, Mosby, 2008.

National Eye Institute: "Facts About Refractive Errors" and "Facts About Myopia."

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