astigmatism: Meaning and Definition of

a•stig•ma•tism

Pronunciation: (u-stig'mu-tiz"um), [key]
— n.
  1. Also calleda refractive error of the eye in which parallel rays of light from an external source do not converge on a single focal point on the retina.
  2. an aberration of a lens or other optical system in which the image of a point is spread out along the axis of the system.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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