What Is Myopia (Nearsightedness)?

Is it hard to see distant objects, like highway signs, until you’re a few feet away, but easy to read a book up close? Chances are you’re myopic, also known as nearsighted. It’s a pretty common condition that your eye doctor usually can fix with eyeglasses, contacts, or eye surgery.

What Causes Myopia?

The structure of your eye is to myopia vision vs normal visionblame. 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.

High myopia: It’s a more serious form of the condition, where the eyeball grows more than it is supposed to and becomes very long front to back. Besides making it hard to see things at a distance, it can also raise your chance of having other conditions like a detached retina, cataracts, and glaucoma.

Degenerative myopia: Also called pathological or malignant myopia, it is a rare type you usually inherit from the genes of your parents. Your eyeball gets longer very quickly and causes severe myopia, usually by the teenage or early adult years. This type of myopia can get worse far into adulthood. Besides making it hard to see things at a distance, you may have a higher chance of having a detached retina, abnormal blood vessel growth in the eye (choroid neovascularization), and glaucoma.

Symptoms

Chances are the only symptom is that more distant objects are blurred. You may also notice:

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

Diagnosis and Treatment

An eye exam can show you if you’re myopic. Glasses, contacts, or refractive surgery can usually correct the problem.

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.

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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 myopia 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 myopia. The surgeon uses a laser or another tool to create a thin flap on the top of your cornea. He sculpts the cornea with another laser and moves the flap back into place.

Does It Get Better Over Time?

Myopia 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 October 04, 2017

Sources

SOURCES:

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

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

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