refractive error

(redirected from spectacle refraction)

refractive error

[rifrak′tiv]
a defect in the ability of the lens of the eye to focus an image accurately, as occurs in nearsightedness and farsightedness.

refractive error

Ametropia, 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.

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.

refractive

capacity to refract light.

refractive error
a difference between the focal length of the cornea and lens, and the length of the eye, resulting in myopia or hyperopia.
refractive media
of the eye include the vitreous humor and the lens.
References in periodicals archive ?
Simply enter the spectacle refraction (without BVD) for right and left eyes, including reading add and dominant eye, and the app gives an initial lens power recommendation.
Users select the lens type they want, enter the spectacle refraction and the recommended trial lens power is shown in a bar below.
SAUFLON HAS launched an online calculator which is designed to assist practitioners in accurate contact lens selection for its core or XR toric prescriptions by simply inputting spectacle refraction and back vertex distance values.
Most laboratories will need to be provided with spectacle refraction, along with the back vertex distance (BVD), as well as the K readings (to two decimal places).
Terminology Explanation Spectacle refraction The spherical and cylindrical combination required, at a stated vertex distance, to correct the patient's ametropia Ocular refraction The spectacle refraction adjusted by compensating for the back vertex distance (BVD) Spectacle astigmatism Can occur either from corneal and/or lenticular astigmatism.
75DS spectacle refraction if contact lenses are worn), and the uncorrected vision must be at least 6/20 (0.
A 54-year-old patient has the spectacle refraction shown in Image C.
If the patient in Question 5 and with the spectacle refraction shown in Image C decides to opt for monovision correction, which of the following would be the MOST appropriate lens powers to select initially?
RGP fittings are usually done from a trial set or ordering empirically from the "K" readings (keratometer reading) along with the spectacle refraction and back vertex distance (BVD).