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a lens used in refraction to determine the strength and axis of a cylindric lens to correct astigmatism; a combination of concave and convex cylinders of like power with axes that are at right angles to each other.
Farlex Partner Medical Dictionary © Farlex 2012
Two cylindrical lenses at right angles to each other; used in diagnosing astigmatism.
See also: cylinder
Medical Dictionary, © 2009 Farlex and Partners