Eye and Vision
Good vision has its origin in the accurate focusing of sharp images on the retina of the eye. If the light is not focused directly on the retina but in front of or behind it, the result is blurry vision. This is called a refractive error.
Human eye and vision
Good vision has its origin in the accurate focusing of sharp images on the retina of the eye.
Nearsightedness or myopia
For the nearsighted eye, objects at a far distance are not focused correctly.
Farsightedness or hyperopia
For the farsighted eye, objects at a close distance are out of focus.
The ability of the eye lens to change its shape in order to focus on different distances decreases with age. As a result, every person with normal vision (starting at approximately age 40 - 45) will need reading glasses for close-up vision.