What cause near-sided?

What cause near-sided?
What Causes Nearsightedness also know as Myopia?
People who are nearsighted have what is call a refractive error. In people next to myopia, the eyeball is too long or the cornea has too much curvature, so the reading light entering the eye is not focused correctly. Images focus in front of the retina, the light-sensitive sector of the eye, rather than directly on the retina, cause blurred vision.
What Are the Symptoms of Myopia?
People who are nearsighted regularly complain of headaches, eyestrain, squinting, or fatigue when driving, playing sports, or looking more than a few foot away.
How Is Myopia Treated?
1. Glasses, contact lenses, or refractive surgery can correct myopia.
2. With myopia, your prescription for glasses or contact lens is a refusal number, such as -3.00. The higher the number, the stronger your lenses will be. The prescription help the eye focus light on the retina, clearing up the reverie.
3. Refractive surgery can reduce or even exterminate your dependence on glasses or contact lenses.
Having something other drawing your attention from the side.