anisocoria
Pronunciation: an-eye-so-KOR-ee-ah
Unequal pupil sizes, which may indicate neurological pathology or be a benign anatomical variant.
Full Definition
Anisocoria describes a condition where the pupils are of unequal size, with a difference typically greater than 0.4mm being considered clinically significant. This finding can indicate serious neurological conditions such as third cranial nerve palsy, Horner's syndrome, or increased intracranial pressure, but may also be physiological in approximately 20% of the population. Clinical documentation must specify whether anisocoria is new-onset or chronic, and whether it varies with lighting conditions. The term appears frequently in emergency department notes, neurological examinations, and ophthalmology reports where precise measurement and description are critical.
Usage
Usage note: Distinguish from mydriasis (pupil dilation) and miosis (pupil constriction), which describe pupil size rather than asymmetry.
In Context
- "Examination revealed 2mm anisocoria with the right pupil larger than the left and poorly reactive to light." — Emergency department note
- "The patient's longstanding anisocoria was documented as physiological with no neurological significance." — Ophthalmology consultation