astigmatism


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astigmatism
top: normal eye with light focusing on the retina
bottom: astigmatic eye with light focusing in different places on or in front of the retina

a·stig·ma·tism

 (ə-stĭg′mə-tĭz′əm)
n.
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 one point on the retina, resulting in blurred vision.

[a- + Greek stigma, stigmat-, point (from stizein, stig-, to tattoo; see steig- in Indo-European roots).]

as′tig·mat′ic (ăs′tĭg-măt′ĭk) adj. & n.
as′tig·mat′i·cal·ly adv.

astigmatism

(əˈstɪɡməˌtɪzəm) or

astigmia

n
1. (General Physics) 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. (Pathology) faulty vision resulting from defective curvature of the cornea or lens of the eye

a•stig•ma•tism

(əˈstɪg məˌtɪz əm)

n.
1. Also called a•stig•mi•a (əˈstɪg mi ə) 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. an aberration of a lens or other optical system in which the image of a point is spread out along the axis.
[1840–50]

a·stig·ma·tism

(ə-stĭg′mə-tĭz′əm)
A defect of the eye in which the curvature of the cornea or lens is uneven. This prevents rays of light from being focused at a single point on the retina, resulting in indistinct or imperfect images.

astigmatism

a defect in a lens, eye, or mirror that causes rays from one direction not to focus at one point. — astigmatic, adj.
See also: Eyes
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.astigmatism - (ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea; common in nearsighted people
ophthalmology - the branch of medicine concerned with the eye and its diseases
ametropia - (ophthalmology) faulty refraction of light rays in the eye as in astigmatism or myopia
keratectasia - abnormal bulging of the cornea of the eye
keratoconus - abnormal cone-shaped protrusion of the cornea of the eye; can be treated by epikeratophakia
2.astigmatism - (optics) defect in an optical system in which light rays from a single point fail to converge in a single focal point
optics - the branch of physics that studies the physical properties of light
condition, status - a state at a particular time; "a condition (or state) of disrepair"; "the current status of the arms negotiations"
stigmatism - (optics) condition of an optical system (as a lens) in which light rays from a single point converge in a single focal point
Translations

astigmatism

[æsˈtɪgmətɪzəm] Nastigmatismo m

astigmatism

[əˈstɪgmətɪzəm] nastigmatisme m

astigmatism

astigmatism

[æsˈtɪgmətɪzm] nastigmatismo

a·stig·ma·tism

[MIM*603047]
n. astigmatismo, defecto de la visión a causa de una irregularidad en la curvatura del ojo.

astigmatism

n astigmatismo
References in periodicals archive ?
The new "Transform" campaign illustrates the unique and life-changing benefits of SynergEyes advanced technology contact lenses for both Independent ECPs and their patients, supporting the SynergEyes goal of delivering solutions for astigmatism, presbyopia and irregular corneas.
The Acuvue Oasys range is said to offer coverage for up to 99% of astigmatic and spherical patients, with nearly 5,000 parameter combinations for Acuvue Oasys for Astigmatism.
ASTIGMATISM This is an uneven curvature of the transparent cornea, which covers the front of the eye causing distorted vision that blurs small print.
Food and Drug Administration (FDA) approval and is launching in the United States for the treatment of cataract patients with pre-existing corneal astigmatism.
It means in, less than an hour, the clouds have gone, but patients may still require glasses for reading or to correct astigmatism - this is caused when the eye becomes rugby-ball shaped rather than round.
People with Astigmatism can benefit better with CIBA Visions Air Optix for Astigmatism because of its exceptional comfort and performance resulting to a whiter, healthy looking eyes and clear stable vision.
They bring together ophthalmologists from the US, South America, and Europe in 27 chapters that address all surgical methods for correcting astigmatism, including corneal incisional surgery, laser refractive surgery, and new intraocular toric lenses, and in this edition, the management of irregular corneal astigmatism and corneal thinning.
Adolescent vision screenings may miss farsightedness and astigmatism, according to a study in the July Archives of Ophthalmology.
Many people have slight astigmatism that requires no treatment.
Summary: Since the Lasik procedure emerged nearly two decades ago, millions of myopia and astigmatism sufferers have permanently tossed their glasses and contact lenses aside.
People with astigmatism and cataracts may benefit from a revised Medicare rule extending coverage for the new type of implantable lenses that treats both conditions.
With some tweaking, could nearsightedness and astigmatism be treated as well?