noun Pathology.
the forward displacement of an organ.

1670–80; < Neo-Latin < Greek próptōsis a fall forward. See pro-2, ptosis

proptosed [prop-tohst] , proptotic [prop-tot-ik] , adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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World English Dictionary
proptosis (prɒpˈtəʊsɪs)
n , pl -ses
pathol See also exophthalmos Compare prolapse the forward displacement of an organ or part, such as the eyeball
[C17: via Late Latin from Greek, from propiptein to fall forwards]

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American Heritage
Medical Dictionary

proptosis prop·to·sis (prŏp-tō'sĭs)
n. pl. prop·to·ses (-sēz)
Forward displacement of an organ, especially an eyeball.

prop·tot·ic (-tŏt'ĭk) adj.
The American Heritage® Stedman's Medical Dictionary
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Encyclopedia Britannica


abnormal protrusion of one or both eyeballs. The most common cause for unilateral or bilateral exophthalmos is thyroid eye disease, or Graves ophthalmopathy. The proptosis arises from inflammation, cellular proliferation, and accumulation of fluid in the tissues that surround the eyeball in its socket, or orbit. The vast majority of people with Graves ophthalmopathy also have (or will later develop) thyroid dysfunction. Other causes of exophthalmos include other orbital inflammatory conditions, spread of infection from the paranasal sinuses or teeth, trauma, various orbital tumours, and vascular (blood vessel) abnormalities of the orbit. It should also be noted that "prominent" eyes can be a normal inherited trait in certain families

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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