A 40-year-old man is found to have small, irregular pupils that react poorly to light but constrict briskly and slowly to a near target, with slow redilation. There is no ptosis or anisocoria of significance. This pupillary finding is classically associated with:

• A Multiple sclerosis
• B Diabetes mellitus
• C Chronic alcoholism
• D Neurosyphilis ✓

Explanation

The Argyll Robertson pupil is small, irregular, and shows light-near dissociation with poor light reaction but brisk near response, classically described in tabes dorsalis and general paresis of neurosyphilis. The lesion is thought to be in the dorsal midbrain near the pretectal nuclei, sparing the more ventral near-response fibres. Diabetes can cause pupillary autonomic neuropathy but does not produce this classic dissociation, making option B the tempting distractor to eliminate.

Reference: Kanski's Clinical Ophthalmology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.