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.
Click for a side-by-side comparison of meanings. Use the word comparison feature to learn the differences between similar and commonly confused words.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use astigmatism in a sentence
This is further backed by statistics regarding astigmatism, a condition that affects almost 33% of the US population.
When a child holds his head to one side constantly on looking at objects, astigmatism, an error of eyesight, is usually indicated.The Mother and Her Child | William S. Sadler
This is usually attributed to the presence of an irregular astigmatism situated near the asymmetric meridian.Schweigger on Squint | C. Schweigger
If the subject cannot read up to the twenty-foot line, nearsightedness or astigmatism is indicated.The Science of Human Nature | William Henry Pyle
Short sight or long sight is often associated with astigmatism, so that suitable spectacles cannot be very easily provided.
If the lines appear with unequal distinctness, some irregularity of refraction (astigmatism) is indicated.Physics | Willis Eugene Tower
British Dictionary definitions for astigmatism
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
Scientific definitions for astigmatism
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.
Cultural definitions for astigmatism
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.