Mnemonic Monday: Argyll-Robinson Pupil
To remember the ocular symptoms of Argyll-Robinson Pupil, just take the first letter of each word – ARP – and read it forwards and backwards. Forwards, you have ARP – Accommodation Reflex Present. Backwards, you have PRA – Pupillary Reflex Absent.
Usually the constriction to light is stronger than constriction to a near stimulus, but the reverse is true in the case of Argyll-Robinson pupil. Remember that “accommodation” refers to the ability of the eyes to focus on a near object. This reflex is carried out in part by pupillary constriction – so the pupils will constrict as you bring a far object into the near eye field – for example, moving your finger close to the patient’s nose. However, the “pupillary reflex” refers to the ability of the eye to constrict when exposed to a bright stimulus, such as your pen light.
Both reflexes include pupillary constriction, and are therefore both mediated through the parasympathetic fibers of the ciliary ganglion. Remember that as long as a patient can sense light, the afferent limb of the pupillary constriction reflex should be intact – therefore, the absence of pupillary constriction in a seeing patient would indicate a defect in the efferent limb. The pre-synaptic cells of this limb lie in the Edinger-Westphal nucleus of CN III.
The term “Argyll-Robinson Pupil” refers to a specific defect as a consequence of tertiary syphilis. However, any lesion resulting in a present accommodation reflex and absent pupillary reflex can be referred to under the more general term “light-near dissociation”. These include Adie’s tonic pupil and Parinaud Syndrome – and since the advent of penicillin, they are much more common in the Western world than Argyll-Robinson pupil.
1. Bouissee, Valerie, and John B. Kerrison, eds. 6th ed. Vol. 1. Lippincott, Williams & Wilkins.
2. Rohkamm, Reinhard. Color Atlas of Neurology. Stuttgart: Thieme, 2004.