Astigmatism

Astigmatism occurs because the cornea has more curvature in one direction or meridian than in the other. Instead of being spherical in shape like a basketball, the cornea is shaped more like a football, and this causes distortion of vision which is called astigmatism. Nobody has a perfectly shaped cornea, but the distortion of most eyes is so slight that it does not significantly affect the quality of vision. However, a significant degree of astigmatism can result in major focusing problems. Astigmatism can occur by itself but often occurs in conjunction with nearsightedness and farsightedness.