Astigmatism is the result of the inability of the cornea to properly focus an image on the retina of the eye. The result is a blurred image.

The cornea is the outermost part of the eye. It is a transparent layer that covers the colored part of the eye (iris), pupil, and lens. The cornea bends light and helps to focus it onto the retina where specialized cells (photo receptors) detect light and transmit nerve impulses via the optic nerve to the brain where the image is formed. The cornea is dome shaped. Any incorrect shaping of the cornea results in an incorrect focusing of the light that passes through that part of the cornea.

Astigmatism is an image distortion that results from an improperly shaped cornea. Usually the cornea is spherical, like a baseball. In astigmatism, the cornea is elliptically shaped, more like a football. This causes...