ocular refraction


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refraction

 [re-frak´shun]
the act or process of refracting; specifically, the determination of the refractive errors of the eye and their correction with glasses.
the deviation of light in passing obliquely from one medium to another of different density.
cycloplegic refraction a type of static refraction, measured after lens accommodation is paralyzed by administration of cycloplegic eye drops.
double refraction refraction in which incident rays are divided into two refracted rays.
dynamic refraction refraction of the eye during accommodation.
ocular refraction the refraction of light produced by the media of the normal eye and resulting in the focusing of images upon the retina.
static refraction refraction of the eye when its accommodation is paralyzed.

ocular refraction

Etymology: L, oculus, eye, refringere, to break apart
an examination of vision to determine the need for corrective lenses.

refraction

(ri-frak'shon) [L. refractio, a breaking back]
1. Deflection from a straight path, as of light rays as they pass through media of different densities; the change in direction of a ray when it passes from one medium to another of a different density.
2. Determination of the amount of ocular refractive errors and their correction.

double refraction

Possession of more than one refractive index, resulting in a double image.
See: birefractive; birefringence

dynamic refraction

The static refraction of the eye plus that accomplished by accommodation; the reciprocal of the near-point distance.

refraction of eye

The refraction brought about by the refractive media of the eye (cornea, aqueous humor, crystalline lens, vitreous body). Synonym: ocular refraction
See: vision pathway

ocular refraction

Refraction of eye.

static refraction

Refraction of the eye when accommodation is at rest or paralyzed.

refractive error 

The dioptric power (K) of the ametropia of the eye. It is equal to 1/k in dioptres, where k is the distance between the far point and either the spectacle plane (spectacle refraction), or the principal point of the eye, or the refracting surface of the reduced eye (ocular refraction), in metres. Thus
K = 1/k
when the eye is situated in air. Syn. ametropia (although this is not strictly so as ametropia is the anomaly); refraction of the eye; refractive status; static refraction. See far point of accommodation; Scheiner's experiment.