WordNet

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

PrepTutorEJDIC

(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）』「2015/10/03 05:54:42」(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

^ "utah.edu". Retrieved 2009-05-27.
^ 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

This medical sign article is a stub. You can help Wikipedia by expanding it.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 成人における詳細な神経学的検査 the detailed neurologic examination in adults
2. 瞳孔不同患者へのアプローチ approach to the patient with anisocoria
3. Overview of eye injuries in the emergency department
4. 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
5. 成人における多発性硬化症の臨床的特徴 clinical features of multiple sclerosis in adults

English Journal

Eye drop neurology.

Bennetto L1, Guly C, Ormerod I, Plant GT.
Practical neurology.Pract Neurol.2014 Jun;14(3):145-51. doi: 10.1136/practneurol-2013-000763. Epub 2014 Feb 11.
Eye drops can help to diagnose and prevent complications of neurological disorders. Guttae ophthalmicae (eye drops) are generally safe because the drugs rarely achieve significant systemic concentrations, although there are rare exceptions. This article covers contemporary pharmacological pupil test
PMID 24520179

PRESBYOPIA-CORRECTING INTRAOCULAR LENSES AND CORNEAL REFRACTIVE PROCEDURES: A Review for Retinal Surgeons.

Ahmad BU1, Shah GK, Hardten DR.
Retina (Philadelphia, Pa.).Retina.2014 Jun;34(6):1046-54. doi: 10.1097/IAE.0000000000000237.
PURPOSE: To review the specific challenges and pitfalls that vitreoretinal surgeons may face when operating on eyes with presbyopia-correcting intraocular lenses or previous corneal refractive surgery. In addition, this review aims to familiarize vitreoretinal surgeons with specifications of current
PMID 24849701

A child with a white pupil.

Lahrouchi N, Bosscha MI, Moll AC.
JAMA : the journal of the American Medical Association.JAMA.2014 May 7;311(17):1799-800. doi: 10.1001/jama.2013.286248.
PMID 24794374

Related Pictures

★リンクテーブル★

リンク元	「マーカス・ガン瞳孔」「afferent pupillary defect」「pupillary disorder」「fixed pupil」「pupil disorder」
関連記事	「pup」

「マーカス・ガン瞳孔」

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