A strange word that causes strange effects to your vision.
Astigmatism is also a refractive error, just like hyperopia and myopia, but it has to do with the curvature of the cornea (the clear part on the front of your eye) and the crystalline lens (inside your eye, behind the iris). There are two different curvatures that focus the image in two different places. This makes vision blurry at all distances. A good example is your facial reflection on the backside of a spoon. The flatter longer curve on the spoon (flatter means less focusing power) will stretch your face reflection. While the steeper shorter curve on the spoon (steeper means more focusing power) will squish your face image. This is why a person with astigmatism needs a multiple-numbered prescription such as -2.00 -1.00 x 180 to see clearly.