astigmatism

American  

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

noun

1. Also called astigmia.  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.

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astigmatism British  

/ əˈstɪɡmɪə, əˈstɪɡməˌtɪzəm /

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

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astigmatism Scientific  

/ ə-stĭg′mə-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.

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astigmatism Cultural  

1. 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.

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Etymology

Origin of astigmatism

First recorded in 1840–50; astigmat(ic) + -ism

Compare meaning

How does astigmatism compare to similar and commonly confused words? Explore the most common comparisons:

• astigmatism vs. myopia

Example Sentences

Lasik was first performed in 1990 to fix near- and farsightedness and astigmatism.

From The Wall Street Journal • Jan. 11, 2026

Schanuel struggled in 2022 with the Harbor Hawks while unknowingly playing with an astigmatism in his right eye.

From Los Angeles Times • Aug. 18, 2023

The professional organization representing optometrists, who perform vision tests and prescribe eyeglasses and contact lenses, praised the draft and recommended adding even more precautions about Lasik surgery for pregnant patients and those with irregular astigmatism.

From New York Times • Dec. 7, 2022

For example, doctors can use lasers instead of cutting eye lenses manually, offer multifocal eye lenses that can eliminate the need for glasses, or recommend the astigmatism fix that Green said she was sold.

From Salon • Oct. 6, 2022

My eyeglasses correct the astigmatism that I got from all the reading in prison.

From "The Autobiography of Malcolm X" by Alex Malcolm X;Hailey