Table: Common Pupillary Abnormalities-MSD Manual Professional Edition

Common Pupillary Abnormalities

Finding	Explanation
Asymmetry of 1–2 mm between pupils, preserved light responses, and no symptoms	Normal variant (physiologic anisocoria)
Asymmetry, impaired light responses, and preserved response to accommodation (light-near dissociation or Argyll Robertson pupil)	Neurosyphilis (possibly)
Bilateral constriction	Opioids Miotic eye drops for glaucoma (most common; causing unilateral constriction if single eye is dosed) Pontine hemorrhage (damaging the central sympathetic pathways that dilate pupils) Organophosphate or cholinergic toxins
Bilateral dilation with preserved light reflexes
Bilateral dilation with impaired direct light response	Brain herniation Hypoxic or ischemic encephalopathy
Unilateral dilation with afferent pupillary defect	Lesions of the eye, retina, or 2nd cranial (optic) nerve
Unilateral dilation with efferent pupillary defect	Third cranial (oculomotor) nerve palsies, often due to compression (eg, due to aneurysm of the posterior communicating artery or to transtentorial herniation) Iris trauma (also irregular pupil) Mydriatic eye drops*
Unilateral dilation with minimal or slow direct and consensual light reflexes and pupil constriction in response to accommodation	Tonic (Adie) pupil†

† Tonic (Adie) pupil is permanent but nonprogressive abnormal dilation of the pupil due to damage of the ciliary ganglion. It typically occurs in women aged 20 to 40. Onset is usually sudden. The only findings are slight blurring of vision, impaired dark adaptation, and sometimes absent deep tendon reflexes.

Finding

Explanation

Asymmetry of 1–2 mm between pupils, preserved light responses, and no symptoms

Normal variant (physiologic anisocoria)

Asymmetry, impaired light responses, and preserved response to accommodation (light-near dissociation or Argyll Robertson pupil)

Neurosyphilis (possibly)

Bilateral constriction

Opioids

Miotic eye drops for glaucoma (most common; causing unilateral constriction if single eye is dosed)

Pontine hemorrhage (damaging the central sympathetic pathways that dilate pupils)

Organophosphate or cholinergic toxins

Bilateral dilation with preserved light reflexes

Bilateral dilation with impaired direct light response

Brain herniation

Hypoxic or ischemic encephalopathy

Unilateral dilation with afferent pupillary defect

Lesions of the eye, retina, or 2nd cranial (optic) nerve

Unilateral dilation with efferent pupillary defect

Third cranial (oculomotor) nerve palsies, often due to compression (eg, due to aneurysm of the posterior communicating artery or to transtentorial herniation)

Iris trauma (also irregular pupil)

Mydriatic eye drops*

Unilateral dilation with minimal or slow direct and consensual light reflexes and pupil constriction in response to accommodation

Tonic (Adie) pupil†

† Tonic (Adie) pupil is permanent but nonprogressive abnormal dilation of the pupil due to damage of the ciliary ganglion. It typically occurs in women aged 20 to 40. Onset is usually sudden. The only findings are slight blurring of vision, impaired dark adaptation, and sometimes absent deep tendon reflexes.