Marcus Gunn pupil

Mar·cus Gunn pu·pil

(mar'kŭs gŭn),

relative afferent pupillary defect.

Synonym(s): Gunn pupil

Marcus Gunn pupil

A change in the pupillary reflex, caused by unilateral optic nerve or retinal disease.

Method
A light is shone, first on one eye and then the other, with the opposite eye covered; the affected eye demonstrates a slight contraction or dilation of the pupil.

Gunn, Robert Marcus

(gun)

Brit. ophthalmologist, 1850–1909.

Gunn dots

White spots occurring on the retina of the eye, close to the macula.

Gunn pupil

, Marcus Gunn pupil

Diminished pupillary reaction to direct light; the symptom is secondary to optic nerve disease.

See: swinging flashlight test

Gunn syndrome

, Marcus Gunn syndrome

A congenital condition in which a ptotic eyelid retracts briefly when the mouth is opened or the jaw is moved to one side. The person appears to wink each time the jaw is opened.

See: jaw winking

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Gunn pupil

, Marcus Gunn pupil

Diminished pupillary reaction to direct light; the symptom is secondary to optic nerve disease.

See: swinging flashlight test

See also: Gunn, Robert Marcus

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pupil

(pu'pil) [L. pupilla, little doll (the reflection in the pupil)]

PUPIL DILATION

The contractile opening at the center of the iris of the eye. It is constricted when exposed to strong light and when the focus is on a near object; is dilated in the dark and when the focus is on a distant object. Average diameter is 4 to 5 mm. The pupils should be equal. See: pupilla; illustration

Differential Diagnosis

Constriction of the pupil occurs, for example, in bright light and after exposure to drugs such as morphine, pilocarpine, physostigmine, eserine, and other miotics.

Dilation of the pupil is most often observed after treatment with mydriatic drugs (such as atropine, scopolamine, or homatropine), but may also be caused by paralysis of cranial nerve III, intracranial masses or trauma, sympathetic nervous system stimulation, and other pupillary stimuli.

Adie pupil

See: Adie, William John

Argyll Robertson pupil

See: Argyll Robertson pupil

artificial pupil

A pupil made by iridectomy when the normal pupil is occluded.

bounding pupil

Rapid dilatation of a pupil, alternating with contraction.

Bumke pupil

Dilatation of the pupil owing to psychic stimulus.

cat's-eye pupil

A pupil that is narrow and slitlike.

cornpicker's pupils

Dilated pupils found in agricultural workers who are exposed to dust from jimsonweed. The dust contains stramonium, a mydriatic.

fixed pupil

A pupil that does not react to stimuli.

Gunn pupil

See: Gunn, Robert Marcus

keyhole pupil

A pupil with an artificial coloboma at the pupillary margin.

luetic pupil

Argyll Robertson pupil.

Marcus Gunn pupil

See: Gunn, Robert Marcus

pinhole pupil

A pupil of minute size; one excessively constricted; seen after use of miotics, in opium poisoning, and in certain brain disorders.

Robertson pupil

See: Argyll Robertson pupil

stiff pupil

Argyll Robertson pupil.

tonic pupil

Adie pupil

Gunn,

Robert Marcus, English ophthalmologist, 1850-1909.

Gunn dots - minute, highly glistening, white or yellowish specks usually seen in the posterior part of the fundus.

Gunn phenomenon - an increase in the width of the eyelids during chewing. Synonym(s): Gunn syndrome; jaw-winking syndrome; Marcus Gunn syndrome

Gunn pupil - Synonym(s): Marcus Gunn pupil

Gunn sign - compression of the underlying vein at arteriovenous crossings seen ophthalmoscopically in arteriolar sclerosis. Synonym(s): Marcus Gunn sign

Gunn syndrome - Synonym(s): Gunn phenomenon

Marcus Gunn pupil - relative afferent pupillary defect. Synonym(s): Gunn pupil

Marcus Gunn sign - Synonym(s): Gunn sign

Marcus Gunn syndrome - Synonym(s): Gunn phenomenon