Anisocoria

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Anisocoria
Anisocoria0.jpg
A large difference in the size of the pupils following application of tropicamide in the right eye only.
Pronunciation
Specialty Ophthalmology   OOjs UI icon edit-ltr-progressive.svg

Anisocoria is a condition characterized by an unequal size of the eyes' pupils. Affecting up to 20% of the population, anisocoria is often entirely harmless, but can be a sign of more serious medical problems.

Contents

Causes

Anisocoria is a common condition, defined by a difference of 0.4 mm or more between the sizes of the pupils of the eyes. [2]

Anisocoria has various causes: [3]

Diagnosis

Causes of anisocoria range from benign (normal) to life-threatening conditions. Clinically, it is important to establish whether anisocoria is more apparent in dim or bright light to clarify if the larger or smaller pupil is the abnormal one.

A relative afferent pupillary defect (RAPD), also known as a Marcus Gunn pupil, does not cause anisocoria.

If the examiner is unsure whether the abnormal pupil is the constricted or dilated one, and if a one-sided drooping of the eyelid is present, then the abnormally sized pupil can be presumed to be the one on the side of the ptosis. This is because Horner's syndrome and oculomotor nerve lesions both cause ptosis.[ citation needed ]

Anisocoria is usually a benign finding, unaccompanied by other symptoms (physiological anisocoria).[ citation needed ] Old face photographs of patients often help to diagnose and establish the type of anisocoria.

Some of the causes of anisocoria are life-threatening, including Horner's syndrome (which may be due to carotid artery dissection) and oculomotor nerve palsy (due to a brain aneurysm, uncal herniation, or head trauma).[ citation needed ]

Acute onset anisocoria should be considered a medical emergency. These cases may be due to brain mass lesions which cause oculomotor nerve palsy. Anisocoria in the presence of confusion, decreased mental status, severe headache, or other neurological symptoms can forewarn a neurosurgical emergency. This is because a hemorrhage, tumor, or other intracranial mass can enlarge to a size where the third cranial nerve (oculomotor nerve) is compressed, resulting in uninhibited dilatation of the pupil on the same side as the lesion. [8]

Etymology

Anisocoria is composed of prefix, root and suffix:

Thus, anisocoria means the condition of unequal pupil(s).

See also

Related Research Articles

<span class="mw-page-title-main">Pupil</span> Part of an eye

The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina. It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil. The size of the pupil is controlled by the iris, and varies depending on many factors, the most significant being the amount of light in the environment. The term "pupil" was coined by Gerard of Cremona.

<span class="mw-page-title-main">Iris (anatomy)</span> Colored part of an eye

The iris is a thin, annular structure in the eye in most mammals and birds, responsible for controlling the diameter and size of the pupil, and thus the amount of light reaching the retina. In optical terms, the pupil is the eye's aperture, while the iris is the diaphragm. Eye color is defined by the iris.

<span class="mw-page-title-main">Mydriasis</span> Excessive dilation of the pupil

Mydriasis is the dilation of the pupil, usually having a non-physiological cause, or sometimes a physiological pupillary response. Non-physiological causes of mydriasis include disease, trauma, or the use of certain types of drug. It may also be of unknown cause.

<span class="mw-page-title-main">Oculomotor nerve</span> Cranial nerve III, for eye movements

The oculomotor nerve, also known as the third cranial nerve, cranial nerve III, or simply CN III, is a cranial nerve that enters the orbit through the superior orbital fissure and innervates extraocular muscles that enable most movements of the eye and that raise the eyelid. The nerve also contains fibers that innervate the intrinsic eye muscles that enable pupillary constriction and accommodation. The oculomotor nerve is derived from the basal plate of the embryonic midbrain. Cranial nerves IV and VI also participate in control of eye movement.

Cycloplegia is paralysis of the ciliary muscle of the eye, resulting in a loss of accommodation. Because of the paralysis of the ciliary muscle, the curvature of the lens can no longer be adjusted to focus on nearby objects. This results in similar problems as those caused by presbyopia, in which the lens has lost elasticity and can also no longer focus on close-by objects. Cycloplegia with accompanying mydriasis is usually due to topical application of muscarinic antagonists such as atropine and cyclopentolate.

<span class="mw-page-title-main">Pupillary light reflex</span> Eye reflex which alters the pupils size in response to light intensity

The pupillary light reflex (PLR) or photopupillary reflex is a reflex that controls the diameter of the pupil, in response to the intensity (luminance) of light that falls on the retinal ganglion cells of the retina in the back of the eye, thereby assisting in adaptation of vision to various levels of lightness/darkness. A greater intensity of light causes the pupil to constrict, whereas a lower intensity of light causes the pupil to dilate. Thus, the pupillary light reflex regulates the intensity of light entering the eye. Light shone into one eye will cause both pupils to constrict.

<span class="mw-page-title-main">Argyll Robertson pupil</span> Medical condition

Argyll Robertson pupils are bilateral small pupils that reduce in size on a near object, but do not constrict when exposed to bright light. They are a highly specific sign of neurosyphilis; however, Argyll Robertson pupils may also be a sign of diabetic neuropathy. In general, pupils that accommodate but do not react are said to show light-near dissociation (i.e., it is the absence of a miotic reaction to light, both direct and consensual, with the preservation of a miotic reaction to near stimulus.

<span class="mw-page-title-main">Miosis</span> Excessive constriction of the pupil

Miosis, or myosis, is excessive constriction of the pupil. The opposite condition, mydriasis, is the dilation of the pupil. Anisocoria is the condition of one pupil being more dilated than the other.

<span class="mw-page-title-main">Horner's syndrome</span> Facial disorder due to damage of the sympathetic nerves

Horner's syndrome, also known as oculosympathetic paresis, is a combination of symptoms that arises when a group of nerves known as the sympathetic trunk is damaged. The signs and symptoms occur on the same side (ipsilateral) as it is a lesion of the sympathetic trunk. It is characterized by miosis, partial ptosis, apparent anhidrosis, with apparent enophthalmos.

<span class="mw-page-title-main">Ciliary ganglion</span> Bundle of nerves, parasympathetic ganglion

The ciliary ganglion is a parasympathetic ganglion located just behind the eye in the posterior orbit. It is 1–2 mm in diameter and in humans contains approximately 2,500 neurons. The ganglion contains postganglionic parasympathetic neurons. These neurons supply the pupillary sphincter muscle, which constricts the pupil, and the ciliary muscle which contracts to make the lens more convex. Both of these muscles are involuntary since they are controlled by the parasympathetic division of the autonomic nervous system.

<span class="mw-page-title-main">Adie syndrome</span> Neurological disorder

Adie syndrome, also known as Holmes–Adie syndrome, is a neurological disorder characterized by a tonically dilated pupil that reacts slowly to light but shows a more definite response to accommodation. It is frequently seen in females with absent knee or ankle jerks and impaired sweating.

<span class="mw-page-title-main">Short ciliary nerves</span> Nerves of the orbit around the eye

The short ciliary nerves are nerves of the orbit around the eye. They are branches of the ciliary ganglion. They supply parasympathetic and sympathetic nerve fibers to the ciliary muscle, iris, and cornea. Damage to the short ciliary nerve may result in loss of the pupillary light reflex, or mydriasis.

<span class="mw-page-title-main">Apraclonidine</span> Chemical compound

Apraclonidine (INN), also known under the brand name Iopidine, is a sympathomimetic used in glaucoma therapy. It is an α2 adrenergic receptor agonist and a weak α1 adrenergic receptor agonist.

<span class="mw-page-title-main">Ptosis (eyelid)</span> Drooping of the upper eyelid over the eye

Ptosis, also known as blepharoptosis, is a drooping or falling of the upper eyelid. This condition is sometimes called "lazy eye", but that term normally refers to the condition amblyopia. If severe enough and left untreated, the drooping eyelid can cause other conditions, such as amblyopia or astigmatism, so it is especially important to treat the disorder in children before it can interfere with vision development.

<span class="mw-page-title-main">Weber's syndrome</span> Medical condition

Weber's syndrome, also known as midbrain stroke syndrome or superior alternating hemiplegia, is a form of stroke that affects the medial portion of the midbrain. It involves oculomotor fascicles in the interpeduncular cisterns and cerebral peduncle so it characterizes the presence of an ipsilateral lower motor neuron type oculomotor nerve palsy and contralateral hemiparesis or hemiplegia.

<span class="mw-page-title-main">Oculomotor nerve palsy</span> Medical condition

Oculomotor nerve palsy or oculomotor neuropathy is an eye condition resulting from damage to the third cranial nerve or a branch thereof. As the name suggests, the oculomotor nerve supplies the majority of the muscles controlling eye movements. Damage to this nerve will result in an inability to move the eye normally. The nerve also supplies the upper eyelid muscle and is accompanied by parasympathetic fibers innervating the muscles responsible for pupil constriction. The limitations of eye movement resulting from the condition are generally so severe that patients are often unable to maintain normal eye alignment when gazing straight ahead, leading to strabismus and, as a consequence, double vision (diplopia).

<span class="mw-page-title-main">Pupillary response</span> Physiological response that varies the size of the pupil

Pupillary response is a physiological response that varies the size of the pupil, via the optic and oculomotor cranial nerve.

The eye is made up of the sclera, the iris, and the pupil, a black hole located at the center of the eye with the main function of allowing light to pass to the retina. Due to certain muscle spasms in the eye, the pupil can resemble a tadpole, which consists of a circular body, no arms or legs, and a tail.

Physiological anisocoria is when human pupils differ in size. It is generally considered to be benign, though it must be distinguished from congenital Horner's syndrome, pharmacological dilatation, or other conditions connected to the sympathetic nervous system. The prevalence of physiological anisocoria has not been found to be influenced by the sex, age, or iris color of the subject.

<span class="mw-page-title-main">Roots of the ciliary ganglion</span>

The ciliary ganglion is a parasympathetic ganglion located just behind the eye in the posterior orbit. Three types of axons enter the ciliary ganglion but only the preganglionic parasympathetic axons synapse there. The entering axons are arranged into three roots of the ciliary ganglion, which join enter the posterior surface of the ganglion.

References

  1. "anisocoria". Dictionary.com Unabridged (Online). n.d.
  2. Lam, BL; Thompson, HS; Corbett, JJ (Jul 15, 1987). "The prevalence of simple anisocoria". American Journal of Ophthalmology. 104 (1): 69–73. doi:10.1016/0002-9394(87)90296-0. PMID   3605282.
  3. John P.Whitcher; Paul Riordan-Eva (2007-10-18). Vaughan & Asbury's general ophthalmology (17th ed.). McGraw-Hill Medical. p. 293. ISBN   978-0071443142.
  4. London, Richard; Richrer Erringer, Ellen; Wyafr, Harry J. (March 1991). "Variation and Clinical Observation With Different Conditions of Illumination and Accommodation". Investigative Ophthalmology & Visual Science. 32 (3): 501–9.
  5. Anisocoria. Medscape Reference. Accessed April 15, 2012.
  6. . It is also seen in some people who consume diphenydramine (brand name "Benadryl") for an extended period of time, or if an astringent eye drop like Visine is used in one eye and not the other, often in concurrence with the presence of contact lenses.van der Donck, I.; Mulliez, E.; Blanckaert, J. (2004), "Angel's Trumpet (Brugmansia arborea) and mydriasis in a child - A case report", Bulletin de la Société Belge d'Ophtalmologie, 292: 53–56, ISSN   0081-0746
  7. "Anisocoria Differential Diagnoses". emedicine.medscape.com. Retrieved 3 June 2017.
  8. Medscape, online. "Anisocoria Clinical Presentation" . Retrieved 25 November 2012.
  9. Hunt, Kevin (January 11, 2016). "The remarkable story behind David Bowie's most iconic feature". The Conversation . Retrieved January 17, 2016.
  10. Rozas C, Frank H, Heynen AJ, Morales B, Bear MF, Kirkwood A (2001). "Developmental inhibitory gate controls the relay of activity to the superficial layers of the visual cortex". J Neurosci. 21 (17): 6791–6801. doi:10.1523/JNEUROSCI.21-17-06791.2001. PMC   6763109 . PMID   11517267.
  11. My Pupils Archived 2013-05-01 at the Wayback Machine , episode 21 of a show
  12. "My Pupils". YouTube . March 25, 2012. Archived from the original on 2021-12-21.

Further reading