Search results
Results from the WOW.Com Content Network
Main page; Contents; Current events; Random article; About Wikipedia; Contact us; Donate; Pages for logged out editors learn more
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 or by a change in the medium. [ 1 ] Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction.
Snell's law (also known as the Snell–Descartes law, the ibn-Sahl law, [1] and the law of refraction) is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air.
Refraction also occurs in oceans when light passes into the halocline where salinity has impacted the density of the water column. For lenses (such as eye glasses ), a lens made from a high refractive index material will be thinner, and hence lighter, than a conventional lens with a lower refractive index.
By measuring this zone, the autorefractor can determine when a patient's eye properly focuses an image. The instrument changes its magnification until the image comes into focus. The process is repeated in at least three meridians of the eye and the autorefractor calculates the refraction of the eye, sphere, cylinder and axis.
Refraction at interface. Many materials have a well-characterized refractive index, but these indices often depend strongly upon the frequency of light, causing optical dispersion. Standard refractive index measurements are taken at the "yellow doublet" sodium D line, with a wavelength (λ) of 589 nanometers.
Main page; Contents; Current events; Random article; About Wikipedia; Contact us; Donate; Pages for logged out editors learn more
Following that "objective refraction" the clinician typically shows the person lenses of progressively higher or weaker powers in a process known as subjective refraction. Cycloplegic agents are frequently used to more accurately determine the amount of refractive error, particularly in children [24]