emmetropia
[em″ĕ-tro´pe-ah] the ideal optical condition, parallel rays coming to a focus on the retina. adj., adj emmetrop´ic.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
em·me·tro·pi·a
(em'ĕ-trō'pē-ă), Do not confuse this word with ametropia.The state of refraction of the eye in which parallel rays, when the eye is at rest, are focused exactly on the retina.
[G. emmetros, according to measure, + ōps, eye]
Farlex Partner Medical Dictionary © Farlex 2012
emmetropia
(ĕm′ĭ-trō′pē-ə)n. The condition of the normal eye when parallel rays of light are focused exactly on the retina and vision is perfect.
em′me·trop′ic (-trŏp′ĭk, -trō′pĭk) adj.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
em·me·tro·pi·a
(em'ĕ-trō'pē-ă) The state of refraction of the eye in which parallel rays, when the eye is at rest, are focused exactly on the retina.
[G. emmetros, according to measure, + ōps, eye]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
emmetropia
The state of the normal eye, with relaxed ACCOMMODATION, in which light rays from a distance (parallel rays) focus accurately on the retina giving perfect vision.Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
emmetropia
The refractive state of the eye in which, with accommodation relaxed, the conjugate focus of the retina is at infinity. Thus, the retina lies in the plane of the posterior principal focus of the eye and distant objects are sharply focused on the retina. This is the ideal refractive state of the eye.
Note: the concept of emmetropia is not simple because accommodation is not inactive when fixating at distance (tonic accommodation). In fact, some authors consider hypermetropia of up to 1.00 D, in a pre-presbyope, as emmetropia.
See resting state of accommodation;
ametropia;
conjugate distances.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann