Astigmatic Eye

Astigmatism

In the normal eye, the cornea is curved the same in the horizontal and vertical directions, like a baseball. When light rays hit the cornea, they focus at a single point. In astigmatism, the curve of the cornea is not the same in the horizontal and vertical directions. The cornea looks like a football, with a steep curve on one side and a flat surface on the other. As a result, light rays entering the cornea do not focus at a single point, instead causing distorted vision. Many people with myopia or hyperopia have some degree of
astigmatism.

For more on other eye problems:

Cataracts
Hyperopia
Myopia
Presbyopia