Astigmatism

Astigmatism is the optical term for more than one point of focus. It occurs when the surface of the cornea or crystalline lens is not spherical. Light from an object may focus on the retina in one direction but not the other.

An astigmatic eye has curves that are steeper in one direction than the other, like a rugby ball. A normal, spherical eye has curves that are the same in all directions, like a football. An astigmatic person will have distorted vision.

Positioning a cylindrical lens in front of an astigmatic eye will refract the light in one direction more than in the other.The power of the lens is not the same all over. It is stronger in certain areas to compensate for the irregular curves on the astigmatic eye. When corrected, an astigmatic person will than see distance and close objects clearly.