refractive error(redirected from spectacle refraction)
a defect in the ability of the lens of the eye to focus an image accurately, as occurs in nearsightedness and farsightedness.
refractive errorAmetropia, myopic shift Ophthalmology The inability of images to focus properly on the retina, often corrected by glasses contact lenses, or refractive surgery. See Astigmatism, Farsightedness, Myopia, Presbyopia.
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/kwhen 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.
capacity to refract light.
a difference between the focal length of the cornea and lens, and the length of the eye, resulting in myopia or hyperopia.
of the eye include the vitreous humor and the lens.