101:
390:
482:. If both surfaces of the lens are curved, consider their curvatures as positive toward the lens and add them. This gives approximately the right result, as long as the thickness of the lens is much less than the
574:
304:(nearsighted) person requires a basic correction of, say, −2 dioptres to restore normal distance vision, might then make a further prescription of 'add 1' for reading, to make up for lack of
217:
are placed close together their powers approximately add. Thus, a thin 2.0-dioptre lens placed close to a thin 0.5-dioptre lens yields almost the same focal length as a single 2.5-dioptre lens.
194:
metre. A flat window has an optical power of zero dioptres, as it does not cause light to converge or diverge. Dioptres are also sometimes used for other reciprocals of distance, particularly
670:
296:
optical power, rather than doing a detailed analysis of the entire optical system (the eye and the lens). Optical power can also be used to adjust a basic
690:
Monoyer, F. (1872). "Sur l'introduction du système métrique dans le numérotage des verres de lunettes et sur le choix d'une unité de réfraction".
736:
866:
835:
251:
The idea of numbering lenses based on the reciprocal of their focal length in metres was first suggested by
Albrecht Nagel in 1866. The term
580:
This is approximately the magnification observed when a person with normal vision holds the magnifying glass close to his or her eye.
339:
is about 11 to 16 dioptres at age 15, decreasing to about 10 dioptres at age 25, and to around 1 dioptre above age 60.
228:, it has not been included in the standard, so that there is no international name or symbol for this unit of measurement—within the
653:
437:
237:
332:
415:
533:
899:
589:
229:
221:
904:
672:
The history & traditions of the
Moorfields Eye Hospital: one hundred years of ophthalmic discovery & development
483:
195:
400:
743:
336:
419:
404:
676:
801:
411:
31:
775:
308:(ability to alter focus). This is the same as saying that −1 dioptre lenses are prescribed for reading.
335:. This results in increased convexity of the lens which in turn increases the optical power of the eye. The
236:(m). However most languages have borrowed the original name and some national standardization bodies like
169:
354:
297:
285:
462:
with a radius of 1/2 metre has a curvature of 2 dioptres. If the curvature of a surface of a lens is
747:
467:
324:
305:
137:
133:
858:
368:(nearsightedness). Typical glasses for mild myopia have a power of −0.50 to −3.00 dioptres.
213:
has the object distance, image distance, and focal length all as reciprocals. Additionally, when
872:
862:
841:
831:
649:
259:
210:
199:
165:
141:
125:
104:
Illustration of the relationship between optical power in dioptres and focal length in metres.
619:
520:
507:
373:
328:
145:
113:
315:
accounts for approximately two-thirds of this refractive power (about 40 dioptres) and the
894:
289:
269:
256:
710:
311:
In humans, the total optical power of the relaxed eye is approximately 60 dioptres. The
100:
320:
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888:
503:
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342:
233:
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157:
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181:
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369:
241:
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599:
357:
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209:
The main benefit of using optical power rather than focal length is that the
876:
845:
614:
604:
594:
451:
346:
264:
214:
232:, this unit for optical power would need to be specified explicitly as the
319:
contributes the remaining one-third (about 20 dioptres). In focusing, the
30:
This article is about the unit of measure in optics. For other uses, see
17:
609:
487:
459:
455:
365:
353:(the limited accommodation of advancing age) to read at close range.
312:
301:
300:
for reading. Thus an eye care professional, having determined that a
161:
779:
646:
Spectacles and Other Vision Aids: A History and Guide to
Collecting
177:
99:
827:
345:
have positive dioptric value and are generally used to correct
383:
293:
118:
569:{\displaystyle V=0.25\ \mathrm {m} \times \varphi +1}
536:
376:
using lenses graded in steps of 0.25 dioptres.
364:have negative dioptric value and generally correct
240:specify a unit name (dioptrie, dioptria, etc.). In
84:
62:
54:
46:
41:
568:
826:. SPIE Field Guides vol. FG01. Bellingham, Wash:
450:The dioptre can also be used as a measurement of
180:. For example, a 3-dioptre lens brings parallel
280:The fact that optical powers are approximately
8:
418:. Unsourced material may be challenged and
360:are rated at +1.00 to +4.00 dioptres.
262:in 1872, based on earlier use of the term
38:
769:
767:
549:
535:
438:Learn how and when to remove this message
349:(farsightedness) or to allow people with
636:
620:Prism correction § Prism dioptres
853:Hecht, Eugene; Alfred, Zając (1987).
800:Palanker, Daniel (October 28, 2013).
508:Magnifying glass § Magnification
152:. It is normally used to express the
7:
416:adding citations to reliable sources
27:Unit of measurement of optical power
804:. American Academy of Ophthalmology
458:measured in metres. For example, a
220:Though the dioptre is based on the
737:"Measuring Vision and Vision Loss"
550:
25:
824:Field Guide to Geometrical Optics
669:Collins, Edward Treacher (1929).
66:
776:"Clinical optics and refraction"
523:is related to its optical power
388:
857:(2nd ed.). Reading, Mass:
802:"Optical Properties of the Eye"
715:La médecine à Nancy depuis 1872
454:equal to the reciprocal of the
331:transferred to the lens by the
644:Rosenthal, J. William (1996).
486:of one of the surfaces. For a
292:as a simple correction to the
1:
230:international system of units
822:Greivenkamp, John E (2004).
498:Relation to magnifying power
474:, the optical power is φ = (
119:
921:
744:Smith-Kettlewell Institute
677:H. K. Lewis & Co. Ltd.
501:
490:the optical power is φ = 2
337:amplitude of accommodation
29:
80:
778:. Eyeweb. Archived from
323:contracts to reduce the
32:Diopter (disambiguation)
255:was proposed by French
735:Colenbrander, August.
692:Annales d'Oculistiques
648:. Norman. p. 32.
570:
215:relatively thin lenses
105:
571:
502:Further information:
286:eye care professional
184:of light to focus at
103:
900:Units of measurement
711:"Monoyer, Ferdinand"
534:
412:improve this section
333:suspensory ligaments
276:In vision correction
248:is frequently used.
144:, equivalent to one
905:Non-SI metric units
484:radius of curvature
468:index of refraction
134:unit of measurement
75:... is equal to ...
566:
196:radii of curvature
106:
92:
86:
868:978-0-201-11609-0
837:978-0-8194-5294-8
548:
448:
447:
440:
290:corrective lenses
260:Ferdinand Monoyer
211:thin lens formula
166:physical quantity
142:reciprocal length
126:American spelling
98:
97:
63:Conversions
16:(Redirected from
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880:
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746:. Archived from
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521:magnifying glass
518:
514:magnifying power
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392:
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374:refractive error
372:usually measure
355:Over the counter
317:crystalline lens
193:
192:
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151:
146:reciprocal metre
122:
121:
114:British spelling
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21:
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358:reading glasses
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270:Johannes Kepler
257:ophthalmologist
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186:
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176:, expressed in
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91:
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35:
28:
23:
22:
15:
12:
11:
5:
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867:
859:Addison–Wesley
850:
836:
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792:
774:Najjar, Dany.
763:
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396:
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381:
378:
362:Concave lenses
321:ciliary muscle
277:
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96:
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65:
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59:
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52:
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44:
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26:
24:
14:
13:
10:
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6:
4:
3:
2:
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843:
839:
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829:
825:
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819:
803:
796:
793:
782:on 2008-03-23
781:
777:
770:
768:
764:
753:on 2014-12-04
749:
745:
738:
731:
728:
716:
712:
705:
702:
698:. Paris: 101.
697:
694:(in French).
693:
686:
683:
678:
674:
673:
665:
662:
657:
655:9780930405717
651:
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504:Magnification
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473:
469:
465:
461:
457:
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407:
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397:This section
395:
391:
386:
385:
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375:
371:
367:
363:
359:
356:
352:
348:
344:
343:Convex lenses
340:
338:
334:
330:
326:
322:
318:
314:
309:
307:
306:accommodation
303:
299:
295:
291:
288:to prescribe
287:
283:
275:
273:
271:
267:
266:
261:
258:
254:
249:
247:
243:
239:
235:
234:inverse metre
231:
227:
226:metric system
223:
218:
216:
212:
207:
205:
204:optical beams
201:
197:
183:
179:
175:
171:
168:equal to the
167:
164:, which is a
163:
159:
155:
154:optical power
147:
143:
139:
135:
131:
127:
123:
115:
111:
102:
90:
83:
79:
76:
73:
71:
67:
61:
57:
53:
50:optical power
49:
45:
40:
37:
33:
19:
854:
823:
806:. Retrieved
795:
784:. Retrieved
780:the original
755:. Retrieved
748:the original
730:
719:. Retrieved
714:
704:
695:
691:
685:
679:p. 116.
671:
664:
645:
639:
579:
519:of a simple
513:
511:
491:
479:
475:
471:
463:
449:
434:
428:January 2015
425:
410:Please help
398:
370:Optometrists
341:
310:
298:prescription
279:
263:
252:
250:
245:
219:
208:
174:focal length
129:
117:
109:
107:
74:
69:
58:dpt, D
47:Unit of
36:
717:(in French)
709:Thomas, C.
590:Astigmatism
284:enables an
244:the symbol
242:vision care
150:1 dpt = 1 m
68:1 dpt
889:Categories
808:2017-10-16
786:2008-03-25
757:2009-07-10
721:2011-04-26
675:. London:
631:References
625:Vertometer
600:Lens clock
351:presbyopia
170:reciprocal
160:or curved
128:), symbol
615:Optometry
605:Lensmeter
595:Dioptrics
558:φ
555:×
452:curvature
399:does not
380:Curvature
347:hyperopia
265:dioptrice
138:dimension
877:13761389
846:53896720
584:See also
466:and the
282:additive
200:vergence
198:and the
88:SI units
420:removed
405:sources
325:tension
253:dioptre
189:⁄
172:of the
132:, is a
120:diopter
110:dioptre
42:dioptre
18:Diopter
895:Optics
875:
865:
855:Optics
844:
834:
652:
610:Optics
547:
488:mirror
460:circle
456:radius
366:myopia
329:stress
313:cornea
302:myopic
178:metres
162:mirror
70:in ...
55:Symbol
751:(PDF)
740:(PDF)
294:eye's
156:of a
136:with
116:) or
873:OCLC
863:ISBN
842:OCLC
832:ISBN
828:SPIE
650:ISBN
544:0.25
512:The
506:and
478:− 1)
403:any
401:cite
182:rays
158:lens
527:by
470:is
414:by
327:or
268:by
238:DIN
202:of
140:of
130:dpt
94:1 m
891::
871:.
861:.
840:.
830:.
766:^
742:.
713:.
696:68
494:.
272:.
222:SI
206:.
148:,
108:A
879:.
848:.
811:.
789:.
760:.
724:.
658:.
576:.
564:1
561:+
551:m
541:=
538:V
525:φ
517:V
492:C
480:C
476:n
472:n
464:C
441:)
435:(
430:)
426:(
422:.
408:.
246:D
224:-
191:3
187:1
124:(
112:(
34:.
20:)
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