Classification and external resources
Pronunciation /ænˌsˈkɔːriə/
Specialty ophthalmology
ICD-10 H57.0
ICD-9-CM 379.41
OMIM 106240
DiseasesDB 724
MedlinePlus 003314
eMedicine emerg/29 neuro/479 oph/160
MeSH D015875

Anisocoria is a condition characterized by an unequal size of the eyes' pupils. Affecting 20% of the population, it can be an entirely harmless condition or a symptom of more serious medical problems.


Anisocoria is composed of prefix, root and suffix:

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


Anisocoria is a common condition, defined by a difference of 0.4 mm or more between the sizes of the pupils of the eyes.[1]

Anisocoria has various causes:[2]


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:

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

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

If the examiner is unsure whether the abnormal pupil is the constricted or dilated one, and if a one-sided ptosis 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.

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

It should be considered an emergency if a patient develops acute onset anisocoria. 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 another intracranial mass can enlarge to a size where the third cranial nerve (CN III) is compressed, which results in uninhibited dilatation of the pupil on the same side as the lesion.[6]

Anisocoria in popular culture

• English singer David Bowie exhibited anisocoria, owing to a teenage injury.[7] Actor Judd Hirsch is also afflicted by this condition.

• In the season 10 Big Bang Theory Comic-Con special, Steve Molaro told a story about how he first met Judd Hirsch and was taken aback by his dilated pupil. One of the other writers researched it and discovered that Judd Hirsch suffers from anisocoria.

See also


  1. 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.
  2. John P.Whitcher; Paul Riordan-Eva. Vaughan & Asbury's general ophthalmology. (17th ed.). McGraw-Hill Medical. p. 293. ISBN 978-0071443142.
  3. 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.
  4. Anisocoria. Medscape Reference. Accessed April 15, 2012.
  5. . 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 Societe Belge d'Ophtalmologie, 292: 53–56, ISSN 0081-0746
  6. Medscape, online. "Anisocoria Clinical Presentation". Retrieved 25 November 2012.
  7. Hunt, Kevin (January 11, 2016). "The remarkable story behind David Bowie's most iconic feature". The Conversation. Retrieved January 17, 2016.

Further reading

External links

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