astigmatism

noun

astig·​ma·​tism ə-ˈstig-mə-ˌti-zəm How to pronounce astigmatism (audio)
1
: a defect of an optical system (such as a lens) causing rays from a point to fail to meet in a focal point resulting in a blurred and imperfect image
2
: a defect of vision due to astigmatism of the refractive system of the eye and especially to corneal irregularity
3
: distorted understanding suggestive of the blurred vision of an astigmatic person

Examples of astigmatism in a Sentence

Recent Examples on the Web The holiday season may pose a unique obstacle for people with astigmatism. Kaitlin Vogel, Health, 21 Dec. 2023 However, there is one thing that can put a damper on your holiday cheer: driving at night with astigmatism. Kaitlin Vogel, Health, 21 Dec. 2023 Glasses prescriptions typically include values for sphere, cylinder, axis and pupillary distance, indicating the lens power, astigmatism correction and the distance between the eyes. Nicole F. Roberts, Forbes, 30 Nov. 2023 Other types of cataract surgery lenses that are not covered by Medicare include toric (for astigmatism) and multifocal, which can correct both near and distance vision. Margie Zable Fisher, Fortune Well, 26 July 2023 It is intended to help optometrists better pinpoint the lenses needed to correct astigmatism, a common imperfection in the eye’s curvature that can make vision blurry and happens to run in Plekhanov’s family. oregonlive, 26 Jan. 2023 Those glasses are real Not unlike this reporter, Beatriz has astigmatism. Rory Appleton, The Indianapolis Star, 25 May 2023 Fichman operates from what looks like a command center that displays images of the eye and makes calculations to break up the cataract with laser energy and address astigmatism. Jake Dressler, Hartford Courant, 7 Oct. 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. Lauren Weber, Fortune, 19 Sep. 2022

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'astigmatism.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

a- entry 2 + Greek stigmat-, stígma "mathematical point, mark, tattoo mark" (more usually stigmḗ in this sense; referring to the point on the retina at which light rays converge in a normal eye) + -ism — more at stigma

Note: The term astigmatism was introduced by the British astronomer George Biddell Airy (1801-92), who performed a pioneering measurement and description of an astigmatism in his own eye ("On a Peculiar Defect of the Eye and a Mode of Correcting It," Transactions of the Cambridge Philosophical Society, vol. 2 [1827], pp. 267-71). Airy did not use the word in the article, however, and it does not seem to appear under his name until a much later article on the same subject, "On a Change in the State of an Eye affected with a Mal-formation [Read May 25, 1846]," Transactions of the Cambridge Philosophical Society, vol. 8 (1849), pp. 361-62. In the latter article Airy describes "the nature of the effect" as "a geometrical phenomenon, to which the term astigmatism was very happily affixed by the present Master of Trinity College." The "Master of Trinity College," Cambridge, was the clergyman and polymath William Whewell (1794-1866), to whom a number of other scientific neologisms are credited. The word was evidently in oral circulation prior to Airy's use of it in print; in 1831, an unsigned article in The British Critic, Quarterly Theological Review, and Eccesiastical Record (vol. 9, p. 82) mentions astigmatism, "employing a word which we believe Professor Airy is in the habit of using in his lectures on this subject [optics]." For details on Airy and astigmatism, see John R. Levene, "Sir George Biddell Airy, F.R.S. (1801-1892) and the Discovery and Correction of Astigmatism," Notes and Records of the Royal Society of London, Vol. 21, No. 2 (December, 1966), pp. 180-199.

First Known Use

1831, in the meaning defined at sense 1

Time Traveler
The first known use of astigmatism was in 1831

Dictionary Entries Near astigmatism

Cite this Entry

“Astigmatism.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/astigmatism. Accessed 21 Jun. 2024.

Kids Definition

astigmatism

noun
astig·​ma·​tism ə-ˈstig-mə-ˌtiz-əm How to pronounce astigmatism (audio)
: a defect of an optical system (as of the eye) that prevents light from focusing accurately and results in a blurred image or unclear vision
astigmatic
ˌas-tig-ˈmat-ik
adjective

Medical Definition

astigmatism

noun
astig·​ma·​tism ə-ˈstig-mə-ˌtiz-əm How to pronounce astigmatism (audio)
1
: a defect of an optical system (as a lens) causing rays from a point to fail to meet in a focal point resulting in a blurred and imperfect image
2
: a defect of vision due to astigmatism of the refractive system of the eye and especially to corneal irregularity compare emmetropia, myopia
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