Lt Col Reynolds
Astigmatism is a condition in which the uneven curvature of the cornea blurs and distorts both distant and near objects. Half or more of Americans have some amount of astigmatism. Dr. Flemings, what else can you tell us about astigmatism?

Lt Col Flemings
Well, Dr. Reynolds, a cornea without astigmatism is round, with even curves from side to side and top to bottom. With astigmatism, the cornea is shaped more like the back of a spoon, curved more in one direction than in another. You may hear astigmatism described as the condition where the cornea is shaped like a football instead of a basketball.

This uneven curvature causes light rays to have more than one focal point, which means the resulting image lands in more than one place on the retina. Astigmatism may be all myopic, or nearsighted; all hyperopic, or farsighted; or a combination of both, or mixed.

Corrections for astigmatism bring all rays of light from different focal points to one focal point. Refractive surgery treatments alter the central cornea by different amounts at different radial orientations to correct for the uneven focus of light rays.