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In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed...

In optics, the refractive index (or refraction index) of an optical medium is the ratio of the apparent speed of light in the air or vacuum to the speed...

ibn-Sahl law, and the law of refraction) is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light...

A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens as its objective to form an image (also referred to a...

Birefringence, also called double refraction, is the optical property of a material having a refractive index that depends on the polarization and propagation...

In optics, negative refraction is the electromagnetic phenomenon where light rays become refracted at an interface that is opposite to their more commonly...

well-characterized refractive index, but these indices often depend strongly upon the frequency of light, causing optical dispersion. Standard refractive index measurements...

Refractive error is a problem with focusing light accurately on the retina due to the shape of the eye and/or cornea. The most common types of refractive...

Seismic refraction is a geophysical principle governed by Snell's Law of refraction. The seismic refraction method utilizes the refraction of seismic waves...

This refraction is due to the velocity of light through air decreasing (the refractive index increases) with increased density. Atmospheric refraction near...

Refractive surgery is an optional eye surgery used to improve the refractive state of the eye and decrease or eliminate dependency on glasses or contact...

A rainbow is an optical phenomenon caused by refraction, internal reflection and dispersion of light in water droplets resulting in a continuous spectrum...

Astigmatism is a type of refractive error due to rotational asymmetry in the eye's refractive power. This results in distorted or blurred vision at any...

Refraction, in acoustics, comparable to the refraction of electromagnetic radiation, is the bending of sound propagation trajectories (rays) in inhomogeneous...

transparent optical element with flat, polished surfaces that are designed to refract light. At least one surface must be angled — elements with two parallel...

In optics, optical power (also referred to as dioptric power, refractive power, focal power, focusing power, or convergence power) is the degree to which...

automated refractor is a computer-controlled machine used during an eye examination to provide an objective measurement of a person's refractive error and...

not exactly equal because of the angular size of the Sun, atmospheric refraction, and the rapidly changing duration of the length of day that occurs at...

is refracted in the same direction as the curvature of Earth's surface. The refractive index of air depends on temperature, giving rise to refraction effects...

Subjective Refraction is a technique to determine the combination of lenses that will provide the best corrected visual acuity (BCVA). It is a clinical...