ametropia /am·e·tro·pia/ (am″ĕ-tro´pe-ah) a condition of the eye in which images fail to come to a proper focus on the retina, due to a discrepancy between the size and refractive powers of the eye.ametrop´ic
ametropia
am·e·tro·pi·a ( m  -tr  p - )n. An eye abnormality, such as nearsightedness, farsightedness, or astigmatism, resulting from faulty refractive ability of the eye. am e·tropic (-tr pk, -trpk) adj. |
ametropia
[am′itrō′pē·ə]
Etymology: Gk, ametros, irregular, opsis, sight
a condition characterized by an optic defect involving an error of refraction, such as astigmatism, hyperopia, or myopia. ametropic, adj.
ametropia
the state when the image of a distant object is not in focus on the retina; due usually to some defect in the refraction of the optic system of the eye.
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).
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).
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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
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