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href="https://ca.wikipedia.org/wiki/Pot%C3%A8ncia_%C3%B2ptica" title="Potència òptica – Catalan" lang="ca" hreflang="ca" data-title="Potència òptica" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Optick%C3%A1_mohutnost" title="Optická mohutnost – Czech" lang="cs" hreflang="cs" data-title="Optická mohutnost" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Optiline_tugevus" title="Optiline tugevus – Estonian" lang="et" hreflang="et" data-title="Optiline tugevus" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%9F%CF%80%CF%84%CE%B9%CE%BA%CE%AE_%CE%B9%CF%83%CF%87%CF%8D%CF%82" title="Οπτική ισχύς – Greek" lang="el" hreflang="el" data-title="Οπτική ισχύς" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Potencia_(%C3%B3ptica)" title="Potencia (óptica) – Spanish" lang="es" hreflang="es" data-title="Potencia (óptica)" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Puissance_optique" title="Puissance optique – French" lang="fr" hreflang="fr" data-title="Puissance optique" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EA%B5%B4%EC%A0%88%EB%A0%A5" title="굴절력 – Korean" lang="ko" hreflang="ko" data-title="굴절력" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D5%95%D5%BA%D5%BF%D5%AB%D5%AF%D5%A1%D5%AF%D5%A1%D5%B6_%D5%B8%D6%82%D5%AA" title="Օպտիկական ուժ – Armenian" lang="hy" hreflang="hy" data-title="Օպտիկական ուժ" data-language-autonym="Հայերեն" data-language-local-name="Armenian" class="interlanguage-link-target"><span>Հայերեն</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Jakost_le%C4%87e" title="Jakost leće – Croatian" lang="hr" hreflang="hr" data-title="Jakost leće" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Daya_optis" title="Daya optis – Indonesian" lang="id" hreflang="id" data-title="Daya optis" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%A2%D7%95%D7%A6%D7%9E%D7%94_%D7%90%D7%95%D7%A4%D7%98%D7%99%D7%AA" title="עוצמה אופטית – Hebrew" lang="he" hreflang="he" data-title="עוצמה אופטית" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%9B%D0%B8%D0%BD%D0%B7%D0%B0%D0%BD%D1%8B%D2%A3_%D0%BE%D0%BF%D1%82%D0%B8%D0%BA%D0%B0%D0%BB%D1%8B%D2%9B_%D0%BA%D2%AF%D1%88%D1%96" title="Линзаның оптикалық күші – Kazakh" lang="kk" hreflang="kk" data-title="Линзаның оптикалық күші" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target"><span>Қазақша</span></a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/Optiskais_stiprums" title="Optiskais stiprums – Latvian" lang="lv" hreflang="lv" data-title="Optiskais stiprums" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target"><span>Latviešu</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%9E%D0%BF%D1%82%D0%B8%D1%87%D0%BA%D0%B0_%D0%BC%D0%BE%D1%9C" title="Оптичка моќ – Macedonian" lang="mk" hreflang="mk" data-title="Оптичка моќ" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%92%E0%B4%AA%E0%B5%8D%E0%B4%B1%E0%B5%8D%E0%B4%B1%E0%B4%BF%E0%B4%95%E0%B5%8D%E0%B4%95%E0%B5%BD_%E0%B4%AA%E0%B4%B5%E0%B5%BC" title="ഒപ്റ്റിക്കൽ പവർ – Malayalam" lang="ml" hreflang="ml" data-title="ഒപ്റ്റിക്കൽ പവർ" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target"><span>മലയാളം</span></a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/%D0%9E%D0%BF%D1%82%D0%B8%D0%BA_%D1%85%D2%AF%D1%87" title="Оптик хүч – Mongolian" lang="mn" hreflang="mn" data-title="Оптик хүч" data-language-autonym="Монгол" data-language-local-name="Mongolian" class="interlanguage-link-target"><span>Монгол</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E5%B1%88%E6%8A%98%E5%8A%9B" title="屈折力 – Japanese" lang="ja" hreflang="ja" data-title="屈折力" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Linsestyrke" title="Linsestyrke – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Linsestyrke" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Zdolno%C5%9B%C4%87_skupiaj%C4%85ca" title="Zdolność skupiająca – Polish" lang="pl" hreflang="pl" data-title="Zdolność skupiająca" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Putere_optic%C4%83" title="Putere optică – Romanian" lang="ro" hreflang="ro" data-title="Putere optică" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%9E%D0%BF%D1%82%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B0%D1%8F_%D1%81%D0%B8%D0%BB%D0%B0" title="Оптическая сила – Russian" lang="ru" hreflang="ru" data-title="Оптическая сила" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Optical_power" title="Optical power – Simple English" lang="en-simple" hreflang="en-simple" data-title="Optical power" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Optick%C3%A1_mohutnos%C5%A5" title="Optická mohutnosť – Slovak" lang="sk" hreflang="sk" data-title="Optická mohutnosť" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9E%D0%BF%D1%82%D0%B8%D1%87%D0%BD%D0%B0_%D1%81%D0%B8%D0%BB%D0%B0" title="Оптична сила – Ukrainian" lang="uk" hreflang="uk" data-title="Оптична сила" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E5%85%89%E5%AD%B8%E5%80%8D%E7%8E%87" title="光學倍率 – Chinese" lang="zh" hreflang="zh" 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from <a href="/w/index.php?title=Refractive_power&redirect=no" class="mw-redirect" title="Refractive power">Refractive power</a>)</span></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Degree to which an optical system converges or diverges light</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">For magnifying power, see <a href="/wiki/Magnification" title="Magnification">Magnification</a>. For the power of light, see <a href="/wiki/Radiant_flux" title="Radiant flux">Radiant flux</a> and <a href="/wiki/Luminous_flux" title="Luminous flux">Luminous flux</a>.</div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Optical_power_of_a_lens.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/7d/Optical_power_of_a_lens.svg/220px-Optical_power_of_a_lens.svg.png" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/7d/Optical_power_of_a_lens.svg/330px-Optical_power_of_a_lens.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/7d/Optical_power_of_a_lens.svg/440px-Optical_power_of_a_lens.svg.png 2x" data-file-width="512" data-file-height="384" /></a><figcaption>Illustration of the relationship between optical power in diopters and focal length in meters.</figcaption></figure> <p>In <a href="/wiki/Optics" title="Optics">optics</a>, <b>optical power</b> (also referred to as <b>dioptric power</b>, <b>refractive power</b>, <b>focusing power</b>, or <b>convergence power</b>) is the degree to which a <a href="/wiki/Lens_(optics)" class="mw-redirect" title="Lens (optics)">lens</a>, <a href="/wiki/Mirror" title="Mirror">mirror</a>, or other optical system converges or diverges light. It is equal to the <a href="/wiki/Multiplicative_inverse" title="Multiplicative inverse">reciprocal</a> of the <a href="/wiki/Focal_length" title="Focal length">focal length</a> of the device: <span class="texhtml"><span class="nowrap"><i>P</i> = 1/<i>f</i></span></span>.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> High optical power corresponds to short focal length. The SI unit for optical power is the <a href="/wiki/Inverse_metre" class="mw-redirect" title="Inverse metre">inverse metre</a> (m<sup>−1</sup>), which is commonly called the <i><a href="/wiki/Dioptre" title="Dioptre">dioptre</a></i> (symbol: dpt). </p><p><a href="/wiki/Converging_lens" class="mw-redirect" title="Converging lens">Converging lenses</a> have positive optical power, while <a href="/wiki/Diverging_lens" class="mw-redirect" title="Diverging lens">diverging lenses</a> have negative power. When a lens is immersed in a <a href="/wiki/Medium_(optics)" class="mw-redirect" title="Medium (optics)">refractive medium</a>, its optical power and focal length change. </p><p>For two or more <a href="/wiki/Thin_lens" title="Thin lens">thin lenses</a> close together, the optical power of the combined lenses is approximately equal to the sum of the optical powers of each lens: <span class="texhtml"><span class="nowrap"><i>P</i> = <i>P</i><sub>1</sub> + <i>P</i><sub>2</sub></span></span>. 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 <a href="/wiki/Optometry" title="Optometry">optometry</a>. </p><p>An <a href="/wiki/Eye" title="Eye">eye</a> that has too much or too little refractive power to <a href="/wiki/Focus_(optics)" title="Focus (optics)">focus</a> light onto the <a href="/wiki/Retina" title="Retina">retina</a> has a <a href="/wiki/Refractive_error" title="Refractive error">refractive error</a>. A <a href="/wiki/Myopic" class="mw-redirect" title="Myopic">myopic</a> eye has too much power so light is focused in front of the retina. This is noted as a minus power. Conversely, a <a href="/wiki/Hyperopic" class="mw-redirect" title="Hyperopic">hyperopic</a> 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 <a href="/wiki/Meridian_(perimetry,_visual_field)" title="Meridian (perimetry, visual field)">meridian</a> that is different from the refractive power of the other meridians has <a href="/wiki/Astigmatism_(eye)" class="mw-redirect" title="Astigmatism (eye)">astigmatism</a>. This is also known as a cylindrical power. <a href="/wiki/Anisometropia" title="Anisometropia">Anisometropia</a> is the condition in which one eye has a different refractive power than the other eye. </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_power&action=edit&section=1" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Accommodation_of_the_eye" class="mw-redirect" title="Accommodation of the eye">Accommodation of the eye</a></li> <li><a href="/wiki/Lens_clock" title="Lens clock">Lens clock</a></li> <li><a href="/wiki/Lensmeter" title="Lensmeter">Lensmeter</a></li> <li><a href="/wiki/Plate_scale" title="Plate scale">Plate scale</a></li> <li><a href="/wiki/Vergence_(optics)" title="Vergence (optics)">Vergence</a></li> <li><a href="/wiki/Vertometer" class="mw-redirect" title="Vertometer">Vertometer</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_power&action=edit&section=2" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFGreivenkamp2004" class="citation book cs1">Greivenkamp, John E. (2004). <i>Field Guide to Geometrical Optics</i>. SPIE Field Guides vol. <b>FG01</b>. SPIE. p. 7. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-8194-5294-7" title="Special:BookSources/0-8194-5294-7"><bdi>0-8194-5294-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Field+Guide+to+Geometrical+Optics&rft.pages=7&rft.pub=SPIE&rft.date=2004&rft.isbn=0-8194-5294-7&rft.aulast=Greivenkamp&rft.aufirst=John+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOptical+power" class="Z3988"></span></span> </li> </ol></div></div> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output 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