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astigmatism

[uh-stig-muh-tiz-uh m]
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noun
  1. 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.
  2. 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. 2018

Examples from the Web for astigmatism

Historical Examples

  • If you don't just see things as they see them, you're troubled with astigmatism.

    The Trail of '98</p>

    Robert W. Service

  • You must see some good oculist about your astigmatism, my dear.

  • To her it was as though her own eyesight were normal, and astigmatism the rule among other people.

    Athalie

    Robert W. Chambers

  • To such let me explain that I am suffering from astigmatism.

    Humorous Ghost Stories

    Dorothy Scarborough

  • A diagram similar to Fig. 394 is used as a test for astigmatism.

    Physics

    Willis Eugene Tower


British Dictionary definitions for astigmatism

astigmatism

astigmia (əˈstɪɡmɪə)

noun
  1. a defect of a lens resulting in the formation of distorted images; caused by the curvature of the lens being different in different planes
  2. 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

Word Origin and History for astigmatism

n.

1849, coined by the Rev. William Whewell (1794-1866), English polymath, from Greek a- "without" (see a- (3)) + stigmatos genitive of stigma "a mark, spot, puncture" (see stick (v.)).

Online Etymology Dictionary, © 2010 Douglas Harper

astigmatism in Medicine

astigmatism

([object Object])
n.
  1. 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
Related formsas′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.

astigmatism in Science

astigmatism

[ə-stĭgmə-tĭz′əm]
  1. 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.

astigmatism in Culture

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.