Related Searches
on Ask.com
astigmatism - 8 dictionary results
a⋅stig⋅ma⋅tism
[uh-stig-muh-tiz-uh
m]
–noun
| 2. | Optics. an aberration of a lens or other optical system in which the image of a point is spread out along the axis of the system. |
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2009.
Cite This Source
Based on the Random House Dictionary, © Random House, Inc. 2009.
Cite This Source
|
Link To astigmatism
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source
Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source
Astigmatism
A*stig"ma*tism\, n. [Gr. 'a priv. + ?, ?, a prick of a pointed instrument, a spot, fr. ? to prick: cf. F. astigmatisme.] (Med. & Opt.) A defect of the eye or of a lens, in consequence of which the rays derived from one point are not brought to a single focal point, thus causing imperfect images or indistinctness of vision. Note: The term is applied especially to the defect causing images of lines having a certain direction to be indistinct, or imperfectly seen, while those of lines transverse to the former are distinct, or clearly seen.
Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.
Cite This Source
Cite This Source
The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source
astigmatism
coined (in form astigmatic) 1849 by English scientist William Whewell (1794-1866), from Gk. a- "without" + stigmatos gen. of stigma "a mark, spot, puncture."
Online Etymology Dictionary, © 2001 Douglas Harper
Cite This Source
Cite This Source
Main Entry: astig·ma·tism
Pronunciation: &-'stig-m&-"tiz-&m
Function: noun
1 : a defect of an optical system (as a lens)causing rays from a point to fail to meet in a focal point resulting in a blurred and imperfect image
2 : a defect of vision due to astigmatism of the refractive system of the eyeand especially to corneal irregularity —compare EMMETROPIA,
Merriam-Webster's Medical Dictionary, © 2002 Merriam-Webster, Inc.
Cite This Source
Cite This Source
astigmatism a·stig·ma·tism (ə-stĭg'mə-tĭz'əm)
n.
A condition in which unequal curvatures along the different meridians in one or more of the refractive surfaces of the eye cause the rays from a light source not to be focused at a single point on the retina. Also called astigmia.
as'tig·mat'ic (ās'tĭg-māt'ĭk) adj. & n.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source
astigmatism (ə-stĭg'mə-tĭz'əm) Pronunciation Key
(click for larger image in new window) A visual defect in which the unequal curvature of one or more refractive surfaces of the eye, usually the cornea, prevents light rays from focusing clearly at a single point on the retina, resulting in blurred vision. |
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
LasikPlus™- Summer Offer
$200 Off, $0 Down 0% for 24 Months. Free LASIK Exam. Call 800-550-3045.
www.LasikPlus.com/California
$200 Off, $0 Down 0% for 24 Months. Free LASIK Exam. Call 800-550-3045.
www.LasikPlus.com/California
Copyright © 2009, Dictionary.com, LLC. All rights reserved.


