Nearsightedness: What Is Myopia?
Myopia (nearsightedness) is a refractive error. Refractive error is when the eye does not bend (refract) light properly. Light does not focus correctly so images are not clear. In myopia, close objects look clear but distant objects appear blurred. Myopia is a common condition that affects an estimated 25% of Americans. It is an eye focusing disorder, not an eye disease.
Myopia in Children
Myopia may be inherited. If a parent has myopia their child may get is as well. Myopia is often discovered in children when they are between ages 8 and 12 years old. During the teenage years, when the body grows rapidly, myopia may become worse. Between the ages of 20 and 40, there is usually little change. Myopia can also occur in adults.
If the myopia is mild, ophthalmologists call this low myopia. They call severe myopia high myopia. High myopia will usually stabilize between the ages of 20-30 years old. Usually, you can correct high myopia with glasses or contact lenses. Sometimes, refractive surgery can correct high myopia.
People with myopia have a higher risk of developing a detached retina. Ask your ophthalmologist to discuss the warning signs of retinal detachment with you. See your ophthalmologist regularly to watch for changes in the retina that might lead to retinal detachment. A surgery can usually repair the retina if you discover the detachment early enough.
People with high myopia may also have a higher risk of developing glaucoma and cataracts.
Nearsightedness: Myopia Symptoms
Some of the signs and symptoms of myopia include:
- squinting to see properly, and
- difficulty seeing objects far away, such as road signs or a blackboard at school.
These symptoms may become more obvious when children are between ages 8 and 12 years old.
Nearsightedness: Myopia Causes
The eye's tear film, cornea and lens bend light so it focuses on the retina. The retina receives the picture formed by these light rays. It sends the picture to the brain through the optic nerve, which is actually part of the brain.
Myopia occurs when the eye is longer than normal or has a cornea that is too steep. As a result, light rays focus in front of the retina instead of on it. In this case, you see near objects clearly, but distant objects will appear blurred. Some studies have found that increased near work and lack of outdoor exposure in childhood may enhance the expression of myopia in some people.