What it is: Myopia is an eye-focusing error. It’s not a disease. Close objects look crisp, but farther ones are blurry. It’s created when the shape of the eye causes light to focus on front of the retina instead of on it. The retina, at the back of the eye, contains the cells that transmit an image to the brain through the optic nerve.
Who it affects: Anyone, although it’s usually inherited. People who do a lot of close work or reading are at higher risk. Between one in three to one in four Americans has myopia. It often becomes obvious in kids between ages 8 and 12, according to the American Academy of Ophthalmology. Nearsightedness tends to worsen until about age 20, when the body is growing fast. Then it pretty much stabilizes (with possible continued changes) until about age 40.
How it’s treated: Glasses or contact lenses are the main treatment. Another option is refractive surgery to reshape the surface of the eye.