Nearsightedness is most often caused by a natural change in the
shape of the eyeball that makes the eyeball too long, so that it is egg-shaped
instead of round. This causes light entering the eye to focus in front of the
retina instead of directly on the retina, causing blurry vision.
In a person with nearsightedness (myopia), close objects can be
seen more clearly than objects that are farther away. Nearsighted people may
squint or frown to see things at a distance. They often hold books or other
objects close to the face, sit at the front of a classroom or movie theater,
and sit close to the television or computer.
Eyeglasses or contact lenses can help correct nearsightedness. Some
people with nearsightedness may also choose to have surgery to change the shape
of the cornea, which can reduce nearsightedness.