[ mi-drahy-uh-sis, mahy- ]
/ mɪˈdraɪ ə sɪs, maɪ- /

noun Medicine/Medical.

excessive dilatation of the pupil of the eye, as the result of disease, drugs, or the like.
Compare miosis.

Origin of mydriasis

1650–60; < Latin mydriāsis < Greek mydríāsis Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for mydriasis

British Dictionary definitions for mydriasis


/ (mɪˈdraɪəsɪs, maɪ-) /


abnormal dilation of the pupil of the eye, produced by drugs, coma, etc

Word Origin for mydriasis

C17: via Late Latin from Greek; origin obscure
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

Medicine definitions for mydriasis


[ mĭ-drīə-sĭs ]


Prolonged abnormal dilation of the pupil of the eye induced by a drug or caused by disease.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.