What Causes Astigmatism?

Published on March 11, 2011

Astigmatism is caused by an irregular shape of the cornea or the lens inside the eye and is often genetic but may also be caused by an injury to the eye. In a normal eye, the cornea is shaped like a basketball, while a cornea affected by astigmatism is shaped like a football. There are two types of astigmatism, regular and irregular.

Regular Astigmatism
Regular astigmatism occurs when the shape of the cornea or crystalline lens is irregular.

Irregular Astigmatism
Irregular astigmatism is often caused by corneal scarring or scattering in the crystalline lens. This type of astigmatism can only be corrected with contact lenses and not with glasses.