emmetropia


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Related to emmetropia: ametropia

emmetropia

 [em″ĕ-tro´pe-ah]
the ideal optical condition, parallel rays coming to a focus on the retina. adj., adj emmetrop´ic.

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]

emmetropia

/em·me·tro·pia/ (em″ĕ-tro´pe-ah) a state of proper correlation between the refractive system of the eye and the axial length of the eyeball, rays of light entering the eye parallel to the optic axis being brought to focus exactly on the retina. Symbol E.emmetrop´ic
Emmetropia.

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.

emmetropia

[em′ətrō′pē·ə]
Etymology: Gk, emmetros, proportioned, opsis, vision
a state of normal vision characterized by the proper relationship between the refractive system of the eyeball and its axial length. This correlation ensures that light rays entering the eye parallel to the optic axis are focused exactly on the retina. Compare amblyopia, hyperopia, myopia. emmetropic, adj.

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]
Enlarge picture
EMMETROPIA, MYOPIA, HYPEROPIA
Enlarge picture
EMMETROPIA, MYOPIA, HYPEROPIA
Enlarge picture
EMMETROPIA, MYOPIA, HYPEROPIA

emmetropia

(em?e-tro'pe-a)
The normal condition of the eye in refraction in which, when the eye is at rest, parallel rays focus exactly on the retina.
See: illustration; astigmatism; myopia

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.

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.

emmetropia

proper coordination of the refractive system and the focal length of the eyeball so that the focused image falls exactly on the retina.
References in periodicals archive ?
34) Thus it has been suggested that it is difficult to conceive how a global process of the eye, such as intraocular pressure or accommodation, could modulate an increase in growth and partial field myopia in one region of the eye while maintaining a normal level of growth towards emmetropia in the remainder of the eye.
Further evidence for the active nature of emmetropisation comes from the observation that, for both spherical refractive errors and astigmatism, the greater the degree of ametropia at birth, the faster the growth tends towards emmetropia.
Another inclusion criterion was that the aim of the surgery was emmetropia.