Argyll Robertson pupils refers to pupils that are bilateral small pupils that reduce in size on a near object but do not constrict when exposed to bright light.
The pupils do not react to light.
AR pupils are a highly specific sign of neurosyphilis.
Argyll Robertson pupils may also be a sign of diabetic neuropathy.
Pupils that accommodate but do not react are said to show light-near dissociation.
It is extremely uncommon in the developed world.
The mechanism which produces an Argyll Robertson pupil is believed to be the result of bilateral damage to the pretectal nuclei in the midbrain, without a focal localising lesion.
The rostral midbrain in the vicinity of the cerebral aqueduct of the third ventricle is the most likely region of damage.
A lesion in this area would involve efferent pupillary fibers on the dorsal aspect of the Edinger-Westphal nucleus.
Such fibers are associated with the response to light, but spare the fibers associated with the response to near vision.
Because syphilis may be an underlying cause, it should be treated, with crystalline penicillin 24 mU intravenous per day for 10 to 14 days.