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cornea

[kawr-nee-uh] /ˈkɔr ni ə/
noun, Anatomy
1.
the transparent anterior part of the external coat of the eye covering the iris and the pupil and continuous with the sclera.
Origin
1350-1400
1350-1400; Middle English < Medieval Latin cornea (tēla, later tunica) horny (web or tunic), feminine of corneus corneous
Related forms
corneal, adjective
multicorneal, adjective
precorneal, adjective
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Examples from the web for cornea
  • Cocaine is rarely used today as an anesthetic, both because of its addictive potential and because it degrades the cornea.
  • Patients with impaired vision because of a damaged cornea could soon regain their sight without need of a human donor transplant.
  • They can even grow blood vessels in the cornea of the eye, where otherwise none will grow.
  • Adult stem cells and cornea stem cells are two other possible sources for generating immature photoreceptor cells.
  • We produce tears in response to insults to the eyes-the sting of onion fumes, a tiny insect that flew into your cornea.
  • The procedure reshapes the cornea by vaporizing cells so that light focuses onto the retina properly.
  • Keratoconus is degeneration of the structure of the cornea.
  • cornea transplants are rarely rejected because the cornea has no blood supply.
  • In this condition, deeper layers of the cornea are involved.
  • The doctor first applies numbing drops to the eye and then uses an ultrasonic wave instrument to measure cornea thickness.
British Dictionary definitions for cornea

cornea

/ˈkɔːnɪə/
noun (pl) -neas (-nɪəz), -neae (-nɪˌiː)
1.
the convex transparent membrane that forms the anterior covering of the eyeball and is continuous with the sclera
Derived Forms
corneal, adjective
Word Origin
C14: from Medieval Latin cornea tēla horny web, from Latin cornūhorn
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for cornea
n.

late 14c., from Medieval Latin cornea tela "horny web or sheath," from Latin cornu (genitive cornus) "horn" (see horn (n.)). So called for its consistency. Related: Corneal.

Online Etymology Dictionary, © 2010 Douglas Harper
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cornea in Medicine

cornea cor·ne·a (kôr'nē-ə)
n.
The transparent, convex, anterior portion of the outer fibrous coat of the eyeball that covers the iris and the pupil and is continuous with the sclera.


cor'ne·al adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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cornea in Science
cornea
  (kôr'nē-ə)   
The tough transparent membrane of the outer layer of the eyeball that covers the iris and the pupil.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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cornea in Culture
cornea [(kawr-nee-uh)]

The transparent outer covering of the front of the eye that covers the iris and pupil.

The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Encyclopedia Article for cornea

dome-shaped transparent membrane about 12 mm (0.5 inch) in diameter that covers the front part of the eye. Except at its margins, the cornea contains no blood vessels, but it does contain many nerves and is very sensitive to pain or touch. It is nourished and provided with oxygen anteriorly by tears and is bathed posteriorly by aqueous humour. It protects the pupil, the iris, and the inside of the eye from penetration by foreign bodies and is the first and most powerful element in the eye's focusing system. As light passes through the cornea, it is partially refracted before reaching the lens. The curvature of the cornea, which is spherical in infancy but changes with age, gives it its focusing power; when the curve becomes irregular, it causes a focusing defect called astigmatism, in which images appear elongated or distorted.

Learn more about cornea with a free trial on Britannica.com
Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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