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13 Essential Literary Terms

pterygium

[tuh-rij-ee-uh m] /təˈrɪdʒ i əm/
noun, plural pterygiums, pterygia
[tuh-rij-ee-uh] /təˈrɪdʒ i ə/ (Show IPA).
Ophthalmology
1.
an abnormal triangular mass of thickened conjunctiva extending over the cornea and interfering with vision.
Origin
1650-1660
1650-60; < Neo-Latin < Greek pterýgion little wing or fin, equivalent to pteryg- (stem of ptéryx) wing, fin + -ion diminutive suffix
Related forms
pterygial, adjective
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Examples from the web for pterygium
  • pterygium is known to induce with-the-rule astigmatism.
  • The corneal curvature along the long axis of the pterygium body is flattened.
  • Recurrent or secondary pterygium often has often a growing fibrovascular tissue more exuberant than the primary.
pterygium in Medicine

pterygium pte·ryg·i·um (tə-rĭj'ē-əm)
n. pl. pte·ryg·i·ums or pte·ryg·i·a (-ē-ə)
An abnormal mass of tissue arising from the conjunctiva of the inner corner of the eye that obstructs vision by growing over the cornea.


pte·ryg'i·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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Encyclopedia Article for pterygium

abnormal wing-shaped fold of the conjunctiva (the mucous membrane lining the eyelids and covering most of the front of the eyeball) that invades the surface of the cornea. Often preceded or accompanied by a pinguecula (yellowish growth in the conjunctiva), pterygia arise from the inner (nasal) or outer (temporal) aspects of the eye. The growth can obscure vision if it encroaches upon the centre of the cornea and thus covers the pupil. Pterygia can contract, altering the shape of the corneal surface and causing astigmatism and blurred vision. Pterygia result from exposure to bright sunlight, wind, and dust, as well as from chronic dryness of the eye. Treatment is surgical removal of the membrane, although recurrence is common in this stubborn affliction.

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