Astigmatism, computer illustration. Astigmatism is a visual disorder in which the eye does not focus light evenly on the retina (turquoise). Light (red lines) in different planes is focused at multiple points. This results in distorted or blurred vision at all distances. It may be a result of irregular curvature of the cornea (the clear, outer layer of the eye, right), or abnormalities in the lens (blue). Astigmatism can be treated using glasses, contact lenses, or surgery.