Argyll Robertson pupil is a miotic pupil associated with which condition?

• A. Diabetes
• B. Multiple sclerosis
• C. Neurosyphilis
• D. Glaucoma

Answer: (C)

Argyll Robertson pupil shows light-near dissociation: the pupil constricts with accommodation (near response) but has little or no constriction to bright light. This happens when the dorsal midbrain pretectal area, which mediates the light reflex, is damaged while the near reflex pathway remains relatively intact. The classic situation for this pattern is neurosyphilis (tertiary syphilis). Other conditions listed don’t produce this distinctive light-near dissociation pattern. So the association is with neurosyphilis.