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ULY CLINIC

21 Septemba 2025, 01:55:08

Argyll Robertson pupil

Argyll Robertson pupil is characterized by a small, irregular pupil that constricts appropriately to near vision (accommodation) but poorly or not at all in response to light. The pupil also shows little or no response to mydriatic agents. It may be unilateral, bilateral, or asymmetric and is classically associated with late neurosyphilis, although other neurologic disorders may cause a similar finding.

Pathophysiology

The light–near dissociation seen in Argyll Robertson pupil results from a lesion in the pretectal region of the midbrain, interrupting fibers mediating the pupillary light reflex while sparing fibers for the near response. In neurosyphilis, chronic meningitis or parenchymal damage affects these pathways. Other conditions (e.g., diabetic neuropathy, midbrain tumors, multiple sclerosis) may cause similar damage, but syphilis remains the classic etiology.

Etiology and Associated Features

Cause	Key Features	Notes
Neurosyphilis (tabes dorsalis, general paresis)	Miotic, irregular pupils; absent light reaction; preserved near response; ataxia, lightning pains, loss of proprioception	Most common classic cause
Diabetic autonomic neuropathy	Small pupils with light-near dissociation	Usually bilateral
Parinaud syndrome / dorsal midbrain lesions	Convergence-retraction nystagmus, upgaze palsy, light-near dissociation	Tumors (pinealoma), infarcts, demyelination
Multiple sclerosis	May produce light-near dissociation if midbrain involved	Other demyelinating signs
Alcoholic neuropathy / chronic meningitis	Rare causes	History and CSF studies help

Clinical examination

Inspect pupil size and shape in ambient light.
Test pupillary light reflex: Shine a bright light into each eye; note sluggish or absent constriction.
Test accommodation response: Ask patient to focus on a near target (e.g., examiner’s finger) — observe brisk pupillary constriction.
Assess symmetry: One or both pupils may be affected, and irregularity is common.
Evaluate for associated neurologic signs: Ataxia, sensory loss, or gait disturbance (tabes dorsalis); cognitive changes (general paresis).

Key point: Preservation of near constriction despite absent light reaction is the hallmark.

Diagnostic approach

Serologic tests for syphilis: VDRL, RPR, FTA-ABS, TP-PA.
CSF analysis if neurosyphilis is suspected.
Neuroimaging (MRI or CT) for dorsal midbrain lesions or other structural causes.
Blood glucose / HbA1c to evaluate diabetic neuropathy.
Consider testing for multiple sclerosis (MRI, CSF oligoclonal bands) in appropriate contexts.

Management

Etiology	Treatment
Neurosyphilis	High-dose intravenous penicillin G (10–14 days), with follow-up CSF studies
Diabetic neuropathy	Optimize glycemic control; symptomatic support
Midbrain lesions (tumor, infarct, MS)	Specific therapy: surgical removal, corticosteroids, or disease-modifying agents
Idiopathic / irreversible	No specific therapy; focus on underlying condition and visual support

Pupillary abnormalities may persist even after successful treatment of the underlying cause.

Patient counseling

Explain that Argyll Robertson pupil is a sign of damage to specific midbrain pathways.
Stress the importance of diagnosing and treating the underlying disorder, especially syphilis.
Recommend regular neurologic and ophthalmologic follow-up, especially if associated with systemic symptoms.

Special considerations

Bilateral involvement is more typical, but asymmetry can occur.
In elderly patients, consider diabetic neuropathy and vascular midbrain lesions.
In younger adults, evaluate for neurosyphilis, demyelinating disease, or tumors.

Key points

Argyll Robertson pupil shows light-near dissociation with small, irregular pupils.
Classic association: neurosyphilis, though modern causes include diabetes and midbrain lesions.
Serology and neuroimaging help identify the cause.
Treatment focuses on the underlying disease; the pupillary defect often persists.

References

Miller NR, Newman NJ, Biousse V, Kerrison JB. Walsh & Hoyt’s Clinical Neuro-Ophthalmology. 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2005.
Biousse V, Newman NJ. Neuro-Ophthalmology Illustrated. 2nd ed. Stuttgart: Thieme; 2012.
Centers for Disease Control and Prevention. Sexually transmitted infections treatment guidelines, 2021. MMWR Recomm Rep. 2021;70(4):1–187.
Ropper AH, Samuels MA, Klein JP. Adams and Victor’s Principles of Neurology. 11th ed. New York: McGraw-Hill; 2019.