Most people have some degree of astigmatism.
Astigmatism is not a disease, but is actually a vision condition that is quite common. The causes of this irregular shape are unclear. In some cases, it may be hereditary or it may result from such factors as pressure of the eyelids on the cornea, incorrect posture or an increased use of the eyes for close work. People with severe astigmatism will usually have blurred or distorted vision.