Astigmatism is often caused by a cornea that is shaped like a football, meaning it is more convex along one axis and flatter along the other. This results in two different focal points in the eye, either in front of the retina or behind the retina. This type of visual defect can cause uneven blurriness around an object or a double image.
In general, astigmatism can be corrected by laser surgery. The laser will proceed to a more or a less profound corneal ablation, according to the axis treated.