pupil

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pupil

 (P) [pu´pil]
the opening in the center of the iris through which light enters the eye; see also Plate 17.
Adie's pupil tonic pupil.
Argyll Robertson pupil one that is miotic and responds to accommodation effort, but not to light.
fixed pupil a pupil that does not react either to light or on convergence, or in accommodation.
Hutchinson's pupil one that is dilated while the other is not.
tonic pupil a usually unilateral condition of the eye in which the affected pupil is larger than the other, responds to accommodation and convergence in a slow, delayed fashion, and reacts to light only after prolonged exposure to dark or light; see also adie's syndrome. Called also Adie's pupil.

pu·pil (p),

(pyū'pĭl), [TA]
The circular orifice in the center of the iris, through which the light rays enter the eye.
Synonym(s): pupilla [TA]
[L. pupilla]

pupil

/pu·pil/ (P) (pu´pil) the opening in the center of the iris through which light enters the eye.pu´pillary
Adie's pupil  tonic p.
Argyll Robertson pupil  one that is miotic and responds to accommodative effort, but not to light.
fixed pupil  one that does not react either to light or on convergence, or in accommodation.
Hutchinson's pupil  one that is dilated while the other is not.
tonic pupil  a usually unilateral condition of the eye in which the affected pupil is larger than the other; responds to accommodation and convergence in a slow, delayed fashion; and reacts to light only after prolonged exposure to dark or light.

pupil

(pyo͞o′pəl)
n.
The apparently black circular opening in the center of the iris of the eye, through which light passes to the retina.

pu′pi·lar, pu′pil·lar·y (-pə-lĕr′ē) adj.

pupil

[pyo̅o̅′pəl]
Etymology: L, pupa, doll
a circular opening in the iris of the eye, located slightly to the nasal side of the center of the iris. Like the iris, the pupil lies posterior to the cornea and the anterior chamber of the eye and is anterior to the lens. Its diameter changes with contraction and relaxation of the muscular fibers of the iris as the eye responds to changes in light, emotional states, and autonomic stimulation. The pupil is the window of the eye through which light passes to the lens and the retina. See also dilator pupillae, sphincter pupillae. pupillary, adj.

pu·pil

(p) (pyū'pil) [TA]
The circular orifice in the center of the iris, through which light rays enter the eye.
Synonym(s): pupilla [TA] .
[L. pupilla]

pupil

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

pupil

The circular opening in the centre of the iris of the eye. The pupil becomes smaller (constricts) in bright light and widens in dim light under the action, respectively of its circular and radial muscle fibres.

pupil

the central opening in the iris of the vertebrate eye through which the light passes to the lens and retina. It changes in size as a result of muscle contraction and expansion moving the iris.

Pupil

The part of the eye that looks like a black circle in the center of the iris. It is actually an opening through which light passes.

pupil 

Aperture within the iris, normally circular, through which light penetrates into the eye. It is located slightly nasally to the centre of the iris. Its diameter can vary from about 2 to 8 mm. It is often slightly smaller in old age. The function of the pupil is to regulate the amount of light admitted into the eye, to optimize the depth of focus and to mitigate ocular aberrations. See acorea; anisocoria; corectopia; dicoria; dyscoria; hippus; iridectomy; microcoria; miosis; dilator pupillae muscle; sphincter pupillae muscle; mydriasis; Edinger-Westphal nucleus; polycoria; polyopia; pupil light reflex.
Adie's pupil A pupil in which the reactions to light, direct or consensual, are almost abolished, with a reaction occurring only after prolonged exposure to light or dark. The reaction of the pupil to a near target is also delayed and slow. The condition is usually unilateral, with the affected pupil being the larger of the two (anisocoria). It may be due to a disease of, or injury to, the ciliary ganglion or to the short ciliary nerves. Other causes include temporal arteritis in elderly patients, syphilis or diabetes. Syn. myotonic pupil; pupillotonia; tonic pupil (some authors use this last term when the cause is known and Adie's pupil when the cause is unidentified). See efferent pupillary defect; Adie's syndrome; pupil light reflex.
amaurotic pupil Miotic pupil that does not react to direct and consensual ipsilateral light stimulation, but does react consensually to contralateral stimulation. It is most often noted in cases of severe optic nerve dysfunction or retinal disease.
apparent pupil See entrance pupil of the eye.
Argyll Robertson pupil Pupil that reacts when the eye accommodates and converges but fails to react directly and consensually to light. The condition is bilateral, the pupils are small and usually unequal. It is usually a sign of neurosyphilis. See iridoplegia; tabes dorsalis.
artificial pupil 1. Pupil made by iridectomy. 2. A circular aperture made in a diaphragm which can be mounted in front of the eye to provide a constant and smaller pupil size. It is used in research but also as a clinical test. See pinhole disc.
pupil block See pupillary block.
pupil constriction See miosis; pupil light reflex.
pupil dilatation See mydriatic; pupil light reflex.
ectopic pupil See corectopia.
entrance pupil of the eye This is the image of the iris aperture formed by the cornea. It is what one sees when one looks at an eye. It is some 13% larger than the real pupil and located slightly in front of it. Syn. apparent pupil (Fig. P23).
exit pupil of the eye This is the image of the iris aperture formed by the crystalline lens. It is slightly larger (,3%) than the real pupil and situated slightly behind it (Fig. P23).
Horner's pupil See syndrome, Horner's.
Hutchinson's pupil A pupil that is dilated and completely inactive to all stimuli. It is associated with lesions of the central nervous system, as may occur in head injury.
keyhole pupil A pupil shaped like a keyhole due to iridectomy in which a section of the iris extending from the pupillary margin to the periphery has been excised, or due to coloboma or trauma to the iris.
pupil light reflex See pupil light reflex.
Marcus Gunn pupil A defect of the pupillary reflex characterized by a smaller constriction of both pupils when the affected eye is stimulated by light as compared to that occurring when the normal eye is stimulated. It is easier, however, to observe this phenomenon when swinging a light from one eye to the other in a darkened room while the subject is fixating a distant object (this is called the swinging flashlight test) (Fig. P24). Stimulation of the normal eye will cause constriction of both pupils whereas rapid stimulation of the affected eye will lead to a small dilatation (a paradoxical reaction, sometimes referred to as pupillary escape). This condition is due to a lesion in one retina or in one of the optic nerves, optic chiasma, optic tract, or the pretectal olivary nucleus that affects the afferent pupillary pathway. It is often the result of central or branch retinal or vein occlusion, extensive retinal detachment, retrobulbar optic neuritis, compressive optic neuropathy, or optic tract lesion, etc. Syn. relative afferent pupillary defect (RAPD), if the magnitude of the effect is partial; afferent pupillary defect (APD), if it is complete.
myotonic pupil See Adie's pupil.
pupil reflex See pupil reflex.
tonic pupil See Adie's pupil.
white pupil See leukocoria.
Fig. P23 The entrance and exit pupils of the eye. E and E′ are the centres of the entrance and exit pupils, respectively (diagram not to scale)enlarge picture
Fig. P23 The entrance and exit pupils of the eye. E and E′ are the centres of the entrance and exit pupils, respectively (diagram not to scale)
Fig. P24 Swinging flashlight test performed in a darkened room. A, stimulation of the normal eye results in bilateral pupil constrictionenlarge picture
Fig. P24 Swinging flashlight test performed in a darkened room. A, stimulation of the normal eye results in bilateral pupil constriction

Table P11 Examples of pupil abnormality
defectappearancelight response*consensual light response*near response
Adie's pupillargeimpairedimpairedslow
Argyll Robertsonboth pupils small, unequal + irregularalmost abolishedalmost abolishednormal
blindness in one eyenormalabolishedabolishednormal
Horner's syndromesmall + ptosisnormalnormalnormal
Hutchinson's pupillargeabolishedabolishedabolished
optic neuritisnormal/largeimpairedimpairednormal
3rd nerve paralysislarge + ptosisabolishedabolishedabolished
*To stimulation of the affected eye.When caused by an aneurysm of the posterior communicating artery.

pu·pil

(pyū'pil) [TA]
Circular orifice in center of iris, through which light rays enter eye.
[L. pupilla]

pupil

the aperture in the center of the iris which regulates the amount of light that reaches the retina.

Adie's pupil
dilated pupil due to parasympathetic denervation.
Argyll Robertson pupil
one that is miotic and responds to accommodation effort, but not to light.
fixed pupil
a pupil that does not react either to light or on convergence, or in accommodation.
multiple p's
polycoria.
occluded pupil
a congenital or acquired pupillary membrane that obstructs the pupil.
secluded pupil
a complete posterior synechia that separates the anterior and posterior chambers of the anterior compartment.
spastic pupil syndrome
anisocoria with pupils that fail to dilate in darkness. Seen in cats infected with feline leukemia virus. The virus has been observed in the short ciliary nerves and ciliary ganglia of some affected cats.
tonic pupil
References in periodicals archive ?
An incident was reported where a child presented with severe proptosis and chemosis, resulting in a sharp decline in vision and a relative afferent pupillary defect.
His visual acuity was 6/6 right and 6/5 left, he had no relative afferent pupillary defect, and his ocular movements were normal.
a Relative afferent pupillary defect b Normal fundal appearance c Papilloedema d Papillitis 03 Considering the history and the fundus photograph shown in Image A, what is the most likely aetiology?
Proptosis was first noticed 10 days prior to his referral, and within 3 days, complete ophthalmoplegia and an afferent pupillary defect appeared in his left eye.
A relative afferent pupillary defect (RAPD) is assessed using a swinging flashlight test, where rapid stimulation of the affected eye will lead to a small dilatation.