Astigmatism

Definition:

A condition in which the cornea of the eye is asymmetrically curved, causing distorted vision.

Causes, incidence, and risk factors:

The cause of astigmatism is unknown. It is usually present from birth, may occur along with nearsightedness or farsightedness, and tends to remain fairly constant. A minor degree of astigmatism is considered normal and does not require correction. Astigmatism is very common.