To understand astigmatism, it is helpful to think of the normal eye as evenly rounded, like a basketball.

With astigmatism, the eye is egg- or oval-shaped like an American football. There are two basic types of astigmatism:

• horizontal astigmatism (when the eye is wider than it is tall), and
• vertical astigmatism (when the eye is taller than it is wide).

With either type of astigmatism, near and far vision is blurry because of the eye’s irregular shape.