A 40-year-old man being evaluated for bilateral small pupils is found to have pupils that are irregular, do not react to light, but constrict briskly and fully on accommodation. Syphilis serology is positive. This pupillary finding is classically termed:

• A Adie's tonic pupil
• B Marcus Gunn pupil
• C Horner pupil
• D Argyll Robertson pupil ✓

Explanation

The Argyll Robertson pupil of neurosyphilis shows bilateral small, irregular pupils with light-near dissociation: absent light reflex with preserved accommodation. It localizes to the dorsal midbrain pretectal region where light reflex fibres synapse, sparing the near-response pathway. Adie's tonic pupil is usually unilateral, large, and shows slow, tonic redilation after near effort. A Horner pupil is miotic with ptosis and reacts normally to light.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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