astigmatism

[ uh-stig-muh-tiz-uhm ]

noun

1. Also called a·stig·mi·a [uh, -, stig, -mee-, uh]. 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.

astigmatism

/ 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

astigmatism

/ 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.

astigmatism

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.

Word History and Origins

Origin of astigmatism¹

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

Example Sentences

Lo and behold, Hernández learned his right eye had astigmatism, a condition caused by imperfections in the curvature of the eye that can result in blurred vision.

From Los Angeles Times

This past winter, Schanuel went to an eye doctor and learned he had astigmatism in his right eye, which was increasingly affecting his ability to see the ball.

From Los Angeles Times

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

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

“He has astigmatism, hypertension, age-related deafness,” his daughter told the newspaper, saying the family had hoped he would be granted a medical dispensation.

From Washington Post