pterygium

[tuh-rij-ee-uhm]
noun, plural pterygiums, pterygia [tuh-rij-ee-uh] . Ophthalmology.
an abnormal triangular mass of thickened conjunctiva extending over the cornea and interfering with vision.

Origin:
1650–60; < Neo-Latin < Greek pterýgion little wing or fin, equivalent to pteryg- (stem of ptéryx) wing, fin + -ion diminutive suffix

pterygial, adjective
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Cite This Source Link To pterygium
American Heritage
Medical Dictionary

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.
Cite This Source
Encyclopedia Britannica
Encyclopedia

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.
Cite This Source
Example sentences
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.
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature