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the contractile aperture in the center of the iris of the eye; resembles a large black dot
young of any of various canines such as a dog or wolf (同)whelp

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(一般にschoolに学ぶ)『生徒』;(個人指導を受けている)生徒,門下生,弟子
ひとみ,瞳孔(どうこう)
=puppy / (キツネ・オオカミ・アザラシなどの)子 / 〈雌犬が〉子犬を生む
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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/12/16 13:05:57」(JST)

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Marcus Gunn pupil or relative afferent pupillary defect (RAPD) is a medical sign observed during the swinging-flashlight test^[1] whereupon the patient's pupils constrict less (therefore appearing to dilate) when a bright light is swung from the unaffected eye to the affected eye. The affected eye still senses the light and produces pupillary sphincter constriction to some degree, albeit reduced.

The most common cause of Marcus Gunn pupil is a lesion of the optic nerve (between the retina and the optic chiasm) or severe retinal disease. It is named after Scottish ophthalmologist Robert Marcus Gunn.^[2]

Examination

The Marcus Gunn pupil is a relative afferent pupillary defect indicating a decreased pupillary response to light in the affected eye.^[3]

In the swinging flashlight test, a light is alternately shone into the left and right eyes. A normal response would be equal constriction of both pupils, regardless of which eye the light is directed at. This indicates an intact direct and consensual pupillary light reflex. When the test is performed in an eye with an afferent pupillary defect, light directed in the affected eye will cause only mild constriction of both pupils (due to decreased response to light from the afferent defect), while light in the unaffected eye will cause a normal constriction of both pupils (due to an intact efferent path, and an intact consensual pupillary reflex). Thus, light shone in the affected eye will produce less pupillary constriction than light shone in the unaffected eye.

A Marcus Gunn Pupil is distinguished from a total CN II lesion, in which the affected eye perceives no light. In that case, shining the light in the affected eye produces no effect.

Anisocoria is absent. A Marcus Gunn pupil is seen, among other conditions, in optic neuritis. It is also common in retrobulbar optic neuritis due to multiple sclerosis but only for 3–4 weeks, until the visual acuity begins to improve in 1–2weeks and may return to normal.^[4]

References

^ "Pupillary Responses". Stanford University School of Medicine. Retrieved 2015-11-04.
^ doctor/2687 at Who Named It?
^ Pearce J (November 1996). "The Marcus Gunn pupil". J. Neurol. Neurosurg. Psychiatr. 61 (5): 520. doi:10.1136/jnnp.61.5.520. PMC 1074053. PMID 8937350.
^ Mumenthaler Neurology 4ed, Thieme 2004, page 486 Demyelinating diseases

External links

1611005962 at GPnotebook

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UpToDate Contents

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1. 成人における詳細な神経学的検査 the detailed neurologic examination in adults
2. 視神経炎：病態生理、臨床的特徴、および診断 optic neuritis pathophysiology clinical features and diagnosis
3. 瞳孔不同患者へのアプローチ approach to the patient with anisocoria
4. 視神経症 optic neuropathies
5. 眼球開放創：緊急評価および初期マネージメント open globe injuries emergent evaluation and initial management

English Journal

Lyme neuroborreliosis: a treatable cause of acute ocular motor disturbances in children.

Correll MH1, Datta N2, Arvidsson HS3, Melsom HA3, Thielberg AK4, Bjerager M4, Brodsky MC5, Saunte JP1.
The British journal of ophthalmology.Br J Ophthalmol.2015 Oct;99(10):1401-4. doi: 10.1136/bjophthalmol-2015-306855. Epub 2015 Apr 13.
BACKGROUND: Lyme neuroborreliosis (LNB) designates central nervous system involvement caused by the tick-borne spirochaete Borrelia burgdorferi (Bb). The present study describes a spectrum of acquired ocular motor disorders in children with LNB.METHODS: Six paediatric patients (age 3-15 years) wit
PMID 25868792

Post-illumination pupil response after blue light: Reliability of optimized melanopsin-based phototransduction assessment.

van der Meijden WP1, Te Lindert BH2, Bijlenga D3, Coppens JE2, Gómez-Herrero G2, Bruijel J2, Kooij JJ3, Cajochen C4, Bourgin P5, Van Someren EJ6.
Experimental eye research.Exp Eye Res.2015 Oct;139:73-80. doi: 10.1016/j.exer.2015.07.010. Epub 2015 Jul 23.
Melanopsin-containing retinal ganglion cells have recently been shown highly relevant to the non-image forming effects of light, through their direct projections on brain circuits that regulate alertness, mood and circadian rhythms. A quantitative assessment of functionality of the melanopsin-signal
PMID 26209783

Pupillary Responses to High-Irradiance Blue Light Correlate with Glaucoma Severity.

Rukmini AV1, Milea D2, Baskaran M3, How AC4, Perera SA4, Aung T3, Gooley JJ5.
Ophthalmology.Ophthalmology.2015 Sep;122(9):1777-85. doi: 10.1016/j.ophtha.2015.06.002.
PURPOSE: To evaluate whether a chromatic pupillometry test can be used to detect impaired function of intrinsically photosensitive retinal ganglion cells (ipRGCs) in patients with primary open-angle glaucoma (POAG) and to determine if pupillary responses correlate with optic nerve damage and visual
PMID 26299721

Related Pictures

★リンクテーブル★

リンク元	「交互点滅対光反射試験」「マーカス・ガン瞳孔」
拡張検索	「Marcus-Gunn pupil」
関連記事	「pup」

「交互点滅対光反射試験」

Marcus Gunn pupil
	The left optic nerve and the optic tracts. A Marcus Gunn pupil indicates an afferent defect, usually at the level of the retina or optic nerve. Moving a bright light from the unaffected eye to the affected eye would cause both eyes to dilate, because the ability to perceive the bright light is diminished.
Classification and external resources
DiseasesDB	29599

　　[★]

英: swinging flashlight test
同: 交互対光反射試験
関: 相対的瞳孔求心路障害 relative afferent pupillary defect RAPD。マーカスガン瞳孔 Marcus Gunn pupil

検査方法：左右の眼に交互に光を当てる。
異常の判断：患側に光を入れても患側の瞳孔が収縮しない。

正常：光＞　・　　○

　　　　　　○　　・　＜光

異常：　　　　　(右眼)
　　　光＞　・　　○

　　　　　　○　　◎　＜光

　　　光＞　・　　○

異常が出るメカニズム：患側の直接反応は、健側の間接反応の方が弱い。そのため、健側から患側に光を当てると、患側の瞳孔が拡張する。
視神経障害(外傷性視神経障害、視神経炎、末期緑内障など)、広範な網膜障害(重度の網膜剥離)
異常がある場合、相対的求心路瞳孔反応異常あり(RAPD relative afferent papillary defect)という。

「マーカス・ガン瞳孔」

　　[★]

英: Marcus-Gunn pupil, Marcus Gunn pupil
同: Marcus-Gunn瞳孔、ガン瞳孔 Gunn pupil
関: 固定瞳孔 fixed pupil、瞳孔疾患 pupil disorder pupillary disorder、瞳孔障害、求心性瞳孔障害 afferent pupillary defect、、

視交差より末梢側の障害による対光反射での瞳孔径不同

「Marcus-Gunn pupil」

　　[★] マーカス・ガン瞳孔

「pup」

　　[★]

子

関: child、filial

[1] "Pupillary Responses". Stanford University School of Medicine. Retrieved 2015-11-04.

[2] doctor/2687 at Who Named It?

[pmid8937350-3] Pearce J (November 1996). "The Marcus Gunn pupil". J. Neurol. Neurosurg. Psychiatr. 61 (5): 520. doi:10.1136/jnnp.61.5.520. PMC 1074053. PMID 8937350.

[4] Mumenthaler Neurology 4ed, Thieme 2004, page 486 Demyelinating diseases

匿名

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案内

案内

Marcus Gunn pupil