Astigmatism

Astigmatism is a general inability of the eye to clearly focus images from any distance because of unequal curvatures of the cornea. Instead of being spherical, an astigmatic cornea has more curvature in one direction than another. It has two curvatures, similar to a football rather than a well-rounded basketball.

Nobody has a perfectly shaped cornea, but the distortion of most eyes is so slight that it does not significantly affect vision. However, more than a small degree of astigmatism can noticeably blur vision. Astigmatism can occur alone or along with nearsightedness or farsightedness.

Most focusing problems like astigmatism can be corrected with corrective lenses or refractive surgery.