Anisocoria Workup

Updated: Mar 29, 2021
  • Author: Eric R Eggenberger, DO, MS, FAAN; Chief Editor: Edsel B Ing, MD, PhD, MBA, MEd, MPH, MA, FRCSC  more...
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Laboratory Studies

Lab studies depend upon the specific etiology.


Imaging Studies

The use of imaging studies depends entirely upon the underlying cause of anisocoria.

Horner syndrome due to lateral medullary syndrome usually can be confirmed by MRI of the head. Imaging of the entire sympathetic pathway with MRI, CT or a combinaiton of these is common in the workup of Horner syndrome. [10]

Carotid dissection may be confirmed with magnetic resonance imaging (MRI) or angiography (MRA), computerized tomography angiography (CTA), contrast angiography, or occasionally Doppler ultrasound, depending on the segment involved, the level of suspicion, and the availability of imaging modalities. A T1-weighted MRI with fat saturation through the carotid course is very helpful sequence when dissection is suspected.

Third nerve palsies with pupillary involvement should be presumed compressive in origin. An enlarging or leaking berry aneurysm, if suggested by the presentation, is often the compressive lesion that requires most immediate diagnosis.

The choice of imaging type is dependent on the suspected pathophysiology: a cerebral aneurysm would be best imaged with angiography, while skull-based neoplasms are best demonstrated by MRI. Imaging decisions are best made in consultation with the local radiologist after a discussion including the region and lesion of interest.



Procedures depend upon the specific etiology.


Histologic Findings

Histologic findings depend upon the specific etiology


Other Tests

Pupillometers can be used to accurately measure pupil size under various lighting conditions. [11]