Astigmatism is caused by an irregular curvature of the cornea or
lens. A cornea without significant astigmatism is shaped like
the side of a basketball (the curvature is uniform over the
entire surface). A cornea with astigmatism is shaped more like
the side of a football (with the curvature being short and steep
in one direction and long and flat in the other). Astigmatism
distorts rays of light in a way that is similar to a funhouse
mirror, making objects look wider, taller or thinner than they
really are. Astigmatism is very common. In fact, most people
have some degree of astigmatism. In most cases, people with
astigmatism are born with this condition. The reason why corneal
shape differs from person to person is unknown, but the
likelihood of developing astigmatism is inherited. Sometimes,
astigmatism can develop after an eye disease, eye injury or
surgery. When the cornea has an irregular shape, it is called
corneal astigmatism. When the shape of the lens is distorted,
you have lenticular astigmatism. A