If the curvature of the cornea is not uniform such as in a sphere, there is a distortion of the image in one direction. This is called astigmatism.
In hyperopia, the eye is shorter than with a normal eye. Depending on the age of the patient this condition can be adjusted by means of accommodation of the eye, so that a clear picture can still be transmitted to the brain. The younger the person is, the better he or she can accommodate. The…
A myopic eye was either longer at birth than the normal eye, or became longer later, often during adolescence. Without optical aids or surgery, the eye cannot provide a clear picture to the brain.
A normal lens is elastic at birth. Because of its elastic property, it can be spherically adapted for the accommodation of the lens to focalize at different distances. The lens needs most accommodation for near distances. Because a child has a very flexible lens, it can see things very close to the eye sharply. The…