In the relaxed state by adjustment, the parallel light is focused on the retina after the refractive system of the eyeball, which is called myopia. Myopia is also known as short-sightedness, because this eye can only see the near and cannot see the far. When this eye is at rest, the parallel light from infinite far place is refracted by the refractive system of the eye, and then it is focused in front of the retina, and the unclear image is formed on the retina. The distance vision is significantly reduced, but the near vision is still normal.