astigmatism

[ uh-stig-muh-tiz-uh m ]
/ əˈstɪg məˌtɪz əm /

noun

Also called a·stig·mi·a [uh-stig-mee-uh] /əˈstɪg mi ə/. Ophthalmology. a 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.
Optics. 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.

Origin of astigmatism

First recorded in 1840–50; astigmat(ic) + -ism
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for astigmatism

British Dictionary definitions for astigmatism

astigmatism

astigmia (əˈstɪɡmɪə)

/ (əˈstɪɡməˌtɪzəm) /

noun

a defect of a lens resulting in the formation of distorted images; caused by the curvature of the lens being different in different planes
faulty vision resulting from defective curvature of the cornea or lens of the eye
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for astigmatism

astigmatism
[ ə-stĭgmə-tĭz′əm ]

n.

A visual defect in which the unequal curvature of one or more refractive surfaces of the eye, usually the cornea, prevents light rays from focusing clearly at one point on the retina, resulting in blurred vision.astigmia

Other words from astigmatism

as′tig•matic (ăs′tĭg-mătĭk) adj. n.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for astigmatism

astigmatism
[ ə-stĭgmə-tĭz′əm ]

A visual defect in which the unequal curvature of one or more refractive surfaces of the eye, usually the cornea, prevents light rays from focusing clearly at a single point on the retina, resulting in blurred vision.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Culture definitions for astigmatism

astigmatism
[ (uh-stig-muh-tiz-uhm) ]

A condition in which the curvature of the cornea of the eye is uneven, causing a blurring of vision. Astigmatism is normally corrected by glasses.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.