ametropia


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Related to ametropia: astigmatism, myopia

ametropia

 [am″ĕ-tro´pe-ah]
an ocular disorder in which parallel rays fail to come to a focus on the retina. adj., adj ametrop´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.

am·e·tro·pi·a

(am-ĕ-trō'pē-ă), Do not confuse this word with emmetropia.
An optic condition in which an error of refraction occurs such that with the eye at rest the retina is not in conjugate focus with light rays from distant objects, that is, only less distant objects are focused on the retina.
[G. ametros, disproportionate, fr. a- priv. + metron, measure, + ōps, eye]
Farlex Partner Medical Dictionary © Farlex 2012

ametropia

(ăm′ĭ-trō′pē-ə)
n.
An eye abnormality, such as nearsightedness, farsightedness, or astigmatism, resulting from faulty refractive ability of the eye.

am′e·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.

am·e·tro·pia

(am'ĕ-trō'pē-ă)
The optic condition in which there is an error of refraction so that with the eye at rest the retina is not in conjugate focus with light rays from distant objects, i.e., only less distant objects are focused on the retina.
[G. ametros, disproportionate, fr. a- priv. + metron, measure, + ōps, eye]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

ametropia

Any deviation, in the relaxed focus of the eye, from the normal state in which distant objects form sharp and clear images on the RETINA. Ametropia may take the form of HYPERMETROPIA, MYOPIA or the meridional visual defect ASTIGMATISM. The state of normal refraction is called emmetropia.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

ametropia 

Anomaly of the refractive state of the eye in which, with relaxed accommodation, the image of objects at infinity is not formed on the retina. Thus vision may be blurred. The ametropias are: astigmatism, hyperopia (hypermetropia) and myopia. The absence of ametropia is called emmetropia. Syn. refractive error; error of refraction; refraction (although not strictly correct since this term may also refer to the lack of ametropia). See hyperopic defocus; myopic defocus; refraction; refractive error; biological-statistical theory; emmetropization theory; nativistic theory.
axial ametropia Ametropia due primarily to an abnormal length of the eye while the refractive power is approximately normal (Fig. A8).
refractive ametropia Ametropia due primarily to an abnormal refractive power of the eye while the length is approximately normal. Refractive ametropias can be attributed to either an abnormal radius of curvature of the surfaces of the cornea, or the crystalline lens (curvature ametropia) or to an abnormal index of refraction of one or more of the ocular media (index ametropia).
Fig. A8 Emmetropia E, axial hyperopia H and axial myopia M. In emmetropia, parallel rays are focused on the retina. In hyperopia, the eye is relatively too short and the principal focus is behind the retinaenlarge picture
Fig. A8 Emmetropia E, axial hyperopia H and axial myopia M. In emmetropia, parallel rays are focused on the retina. In hyperopia, the eye is relatively too short and the principal focus is behind the retina
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
References in periodicals archive ?
Characteristic###Study Population###Group-A (Ametropia)###Group-B (No amteropia)###p-Value
Smith, "Nature of the refractive errors in rhesus monkeys (Macaca mulatta) with experimentally induced ametropias," Vision Research, vol.
Glaucoma 14 Pseudophakia 5 Ametropia 2 Presbiopia 1 Bilateral Retinitis Pigmentosa (BRP) 1 Age related macular degeneration 1 BRP + Psuedophakia 1 Note: Table made from bar graph.
El periodo critico para la instauracion de la ambliopia por deprivacion del estimulo es mas corto que en el estrabismo o las ametropias altas-anisometropias.
Igualmente, se evaluo la respuesta acomodativa o poder dioptrico de compensacion para hallar el valor dinamico neto en la retinoscopia dinamica monocular de Merchan, con la retinoscopia de Nott y MEM en personas menores de 40 anos, a fin de determinar el estado refractivo y el tipo de ametropia en vision lej ana debido a que Merchan utiliza en esta poblacion la compensacion estandar de 1.25 D sin considerar que la respuesta acomodativa mayor a 1.00 D significa que puede haber alguna deficiencia en el mecanismo de acomodacion en este grupo de personas y en mayores de 40 anos de edad (13,14).
After baseline testing, children in the ametropia group received prescription glasses to correct their vision.
Quantification of chick lens [alfa] A - and [delta] crystallins in experimentally induced ametropia. Mol.
This is described as 'defocus-induced' or 'compensatory' ametropia and suggests that blurring of an image on the retina can lead to induction of a refractive error.