Myopia (or nearsightedness) affects 20% to 30% of the population, but this eye disorder is easily corrected with eyeglasses, contact lenses or surgery. People who have myopia or nearsightedness have difficulty seeing distant objects, but can see objects that are near clearly. For example, a person who is nearsighted may not be able to make out highway signs until they are just a few feet away.

Alternative Names of Myopia are: Nearsightedness.

Causes of Myopia

• People who are nearsighted have what is called a refractive error. This means that the light rays bend incorrectly into the eye to transmit images to the brain. In people with myopia, the eyeball is too long or the cornea has too much curvature, so the light entering the eye is not focused correctly. Light rays of images focus in front of the retina, the light-sensitive part of the eye, rather than directly on the retina, causing blurred vision.
• Myopia runs in families and usually appears in childhood. Sometimes the condition plateaus, or sometimes it worsens with age.

Signs & Symptoms of Myopia

People who are nearsighted often complain of headaches, eyestrain, squinting or fatigue when driving, playing sports, or looking more than a few feet away.

Diagnosis of Myopia

Myopia can be easily diagnosed using standard eye exams given by an eye doctor.

Treatments of Myopia

Glasses, contact lenses, or refractive surgery can correct myopia. With myopia, your prescription for glasses or contact lens is a negative number, such as -3.00. The higher the number, the stronger your lenses will be. Refractive surgery can reduce or even eliminate your dependence on glasses or contact lenses. The most common procedures for myopia are performed with a laser, including:

• Photorefractive keratectomy. Also called PRK , a laser is used to remove a layer of corneal tissue, which flattens the cornea and allows light rays to focus closer to or even on the retina.  
• Laser-assisted in situ keratomileusis. Commonly called LASIK , a laser is used to cut a flap through the top of the cornea, a laser removes some corneal tissue, then the flap is dropped back into place. LASIK is the most common surgery used to correct nearsightedness.  
• Corneal rings. Plastic corneal rings, called Intacs, are implanted into the eye to alter the shape of the cornea. One advantage of the rings is that they may be left in place permanently, may be removed in case of a problem, or adjusted should a prescription change be necessary.

Prevention of Myopia

Although nearsightedness (myopia) is easily treated, it cannot be prevented, nor can you keep it from getting worse when you have it. It often gets worse, sometimes rapidly, until the late teens or early 20s, when it usually stabilizes. Nearsightedness does not improve as you get older. Many people believe that too much close work, such as reading or sitting too close to the television, causes nearsightedness. But there was little evidence to support this belief. However, one study suggested that people in professions that involve extensive reading have higher degrees of nearsightedness. Special diets, eye exercises, and medicines will not treat or cure nearsightedness.

When to seek Medical Advice

If you have a sudden change, loss, or disturbance in your vision or you have pain in your eye or yellow or greenish discharge from your eye, see the topic Eye Problems, No injury to evaluate your symptoms. You may need immediate care. Whether you are nearsighted (myopic) or not, doctors recommend having routine eye exams throughout life (see Early Detection in the Exams and Tests section of this topic). In addition to these routine exams, call your doctor if:

• Your child or teenager has symptoms of nearsightedness or any complaints of unclear vision.
• Existing nearsightedness in an adult suddenly becomes worse.
• You have a change in your ability to tolerate your contact lenses (for example, you can no longer wear them for the usual periods of time).
• You see flashes of light, floaters, change in your side vision, or dimming of your vision (these may mean you have retinal detachment).