In optics, optical power (also referred to as dioptric power, refractive power, focusing power, or convergence power) is the degree to which a lens, mirror, or other optical system converges or diverges light. It is equal to the reciprocal of the focal length of the device: P = 1/f.[1] High optical power corresponds to short focal length. The SI unit for optical power is the inverse metre (m−1), which is commonly called the dioptre (symbol: dpt).
Illustration of the relationship between optical power in diopters and focal length in meters.
For two or more thin lenses close together, the optical power of the combined lenses is approximately equal to the sum of the optical powers of each lens: P = P1 + P2. Similarly, the optical power of a single lens is roughly equal to the sum of the powers of each surface. These approximations are commonly used in optometry.
An eye that has too much or too little refractive power to focus light onto the retina has a refractive error. A myopic eye has too much power so light is focused in front of the retina. This is noted as a minus power. Conversely, a hyperopic eye has too little power so when the eye is relaxed, light is focused behind the retina. An eye with a refractive power in one meridian that is different from the refractive power of the other meridians has astigmatism. This is also known as a cylindrical power. Anisometropia is the condition in which one eye has a different refractive power than the other eye.
^Greivenkamp, John E. (2004). Field Guide to Geometrical Optics. SPIE Field Guides vol. FG01. SPIE. p. 7. ISBN0-8194-5294-7.
January 01, 1970
optical, power, magnifying, power, magnification, power, light, radiant, flux, luminous, flux, optics, optical, power, also, referred, dioptric, power, refractive, power, focusing, power, convergence, power, degree, which, lens, mirror, other, optical, system,. For magnifying power see Magnification For the power of light see Radiant flux and Luminous flux In optics optical power also referred to as dioptric power refractive power focusing power or convergence power is the degree to which a lens mirror or other optical system converges or diverges light It is equal to the reciprocal of the focal length of the device P 1 f 1 High optical power corresponds to short focal length The SI unit for optical power is the inverse metre m 1 which is commonly called the dioptre symbol dpt Illustration of the relationship between optical power in diopters and focal length in meters Converging lenses have positive optical power while diverging lenses have negative power When a lens is immersed in a refractive medium its optical power and focal length change For two or more thin lenses close together the optical power of the combined lenses is approximately equal to the sum of the optical powers of each lens P P1 P2 Similarly the optical power of a single lens is roughly equal to the sum of the powers of each surface These approximations are commonly used in optometry An eye that has too much or too little refractive power to focus light onto the retina has a refractive error A myopic eye has too much power so light is focused in front of the retina This is noted as a minus power Conversely a hyperopic eye has too little power so when the eye is relaxed light is focused behind the retina An eye with a refractive power in one meridian that is different from the refractive power of the other meridians has astigmatism This is also known as a cylindrical power Anisometropia is the condition in which one eye has a different refractive power than the other eye See also editAccommodation of the eye Lens clock Lensmeter Plate scale Vergence VertometerReferences edit Greivenkamp John E 2004 Field Guide to Geometrical Optics SPIE Field Guides vol FG01 SPIE p 7 ISBN 0 8194 5294 7 Retrieved from https en wikipedia org w index php title Optical power amp oldid 1181596208, wikipedia, wiki, book, books, library,
