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

Though his vision was 20/12, astigmatism in his right eye had made him left-eye dominant, a subtle but limiting dynamic for a left-handed hitter.

From Los Angeles Times • Jun. 30, 2025

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

But the former English professor said her 2019 surgery with Ophthalmology Consultants didn't get her to 20/20 vision or fix her astigmatism — despite a $3,000 out-of-pocket charge for the astigmatism surgical upgrade.

From Salon • Oct. 6, 2022

When he opened his eyes again, he realized his glasses were gone, and between the dizziness and his astigmatism, the letters before him started dancing.

From "An Abundance of Katherines" by John Green