Eyeworks

Astigmatism is caused by an irregular shape of the cornea,the clear tissue on the front of the eye.  The cornea can basically have two different shapes.  It can be shaped like a basketball, in other words completely spherical.  If that is the case then you don't have astigmatism.  If the cornea has an irregular shape, like a football, then you have astigmatism.  Looking at a football there are two different shapes or curves that are 90 degrees apart.  Since there are two curves, when the light rays hit the cornea, it causes the light to come to a focus at two different points.  Your eyeglasses or contact lenses must have two different curvatures to bring the light rays back to a single focus.