Also called: Nearsightedness; Shortsightedness
Myopia (my-OH-pee-uh) is nearsightedness, a common condition in which someone can see things that are close clearly, but things that are farther away appear blurry.
Myopia is a type of refractive error. This means the problem is caused by the way the eye bends, or refracts, light as it passes through the eye's cornea and lens. Normally, the cornea (the clear front of the eye) and lens (a small structure in the eye that can change shape) work together to take in images and focus them on the retina, the soft, light-sensitive layer of tissue that lines the back of the eyeball wall. When someone has myopia, the lens focuses the image in front of the retina instead of directly on it.
Myopia can happen if the eye is too long or if the cornea has too much curve to it. This may be related to a person's genes or it may be caused environmental conditions, such as a job that involves a lot of reading off of computer screens.
Myopia can cause blurred vision, squinting, eyestrain, and headaches. It also can make things like driving more dangerous when road signs are hard to read. Myopia can affect people of any age, but it's most commonly diagnosed in adolescents during and after puberty.
Myopia is diagnosed through an eye exam. Mild myopia may not need treatment. People with moderate to severe cases may need to wear glasses or contact lenses to correct their vision. For some adults, laser eye surgery can correct myopia permanently by changing the shape of the cornea.
Myopia doesn't cause any pain, but it can have a negative effect on a child's quality of life if not corrected. If your child has trouble seeing things or seems to do a lot of squinting, talk to a doctor and schedule an eye exam. Most cases of myopia can be easily corrected with glasses, contacts, or surgery.
All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.
