Argyll Robertson pupil is defined by light near dissociation with which feature?

• A. Preserved accommodation
• B. Impaired accommodation
• C. No near response
• D. Pupillary dilation with near effort only

Answer: (A)

This sign reflects light–near dissociation where the pupil fails to constrict to bright light but does constrict during near focus. In Argyll Robertson pupils, the light reflex pathway is damaged, so the pupil doesn’t react to illumination, yet the accommodation-convergence pathway remains intact enough to produce constriction when focusing on a near target. That means accommodation is preserved, which is why the best description is preserved accommodation. The other options don’t fit because the near response is present, not absent or impaired, and the pattern is not simply dilation with near effort only. This finding is classically associated with neurosyphilis involving the dorsal midbrain/pretectal area.