What is astigmatism?

Astigmatism arises from a defect in the cornea, or sometimes the lens. It is as if the eyes were not spherical like a football, but instead resembled a rugby ball. 

Vision is blurry at all distances. Eye strain and headaches may reveal astigmatism. There is sensitivity to light and confusion between certain letters. Some lines (for example, vertical ones) appear blurry while others (in this case, horizontal ones) appear sharp. 

Astigmatism is congenital or acquired (for example, following cataract surgery, a transplant, or an accident). 

Surgical correction of astigmatism is achieved by modifying the shape of the corneal surface to regularize the central area, by steepening the flattest meridian and flattening the most curved one.