Nearsightedness is an eye condition that prevents people suffering from it to see far distances clearly. Nearsightedness is also called myopia.
The condition runs in families and affects men and women in equal number. It usually develops in school-age children and stabilizes in the twenties. Nearsightedness may be caused by an overly long eyeball, or from the lens power being too strong. Nearsightedness is also partially genetic.
It relates to the way the eye brings images into focus on the back of the eyeball, where 10 layers of light-sensitive nerve tissue make up the retina. Nearsightedness affects about 20 percent of the population and is the result of images being focused in front of the retina rather than on it. Therefore, distant objects appear blurred to people who are nearsighted. A nearsighted person must hold a book close to the eyes when reading and has to sit in the front of a classroom to see the chalkboard clearly.
