Myopia, or nearsightedness, is a refractive error, which means that the eye does not bend or refract light properly to a single focus to see images clearly. In myopia, close objects look clear but distant objects appear blurred. Myopia is a common condition that affects an estimated 25 percent of Americans. It is an eye focusing disorder, not an eye disease.
Runs in families and usually appears in childhood.
In order for our eyes to be able to see, light rays must be bent or refracted by the tear film, the cornea and the lens so they can focus on the retina, the layer of light-sensitive cells lining the back of the eye. The retina receives the picture formed by these light rays and sends the image 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 (clear front window of the eye) that is too steep. As a result, light rays focus in front of the retina instead of on it. This allows you to see near objects clearly, but distant objects will appear blurred.
Some of the signs and symptoms of myopia include eyestrain, headaches, squinting to see properly and difficulty seeing objects far away, such as road signs or a blackboard at school.
Myopia symptoms may be apparent in children when they are between ages eight 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.