Dilatation of pupils of both eyes when the light stimulus is rapidly transferred from the normal eye (after brief light exposure to the normal eye) to the affected eye. Constriction of pupils of both eyes when the light stimulus is applied to the normal eyeĢ.The presence of a relative afferent pupil defect (RAPD) is the hallmark of a unilateral afferent sensory abnormality or bilateral asymmetric visual loss.Īn afferent pupillary response is characterized by: Hirschberg first noted this phenomenon in the case of unilateral retrobulbar optic neuritis. It is named after Scottish Ophthalmologist Robert Marcus Gunn. A Marcus Gunn pupil, on the other hand, has a relative weakness of the afferent limb of the pupillary light reflex compared to the other eye because of which when light is rapidly transferred from the normal eye to the eye with MGP, the MGP dilates instead of constricting. After exposure to bright light, a normal pupil constricts. In literature, the term is often used synonymously with Marcus Gunn phenomenon or relative afferent pupillary defect (RAPD). Marcus Gunn pupil (MGP) is the term given to an abnormal pupil showing aberrant pupillary response in certain ocular disorders.

Outline the prognosis and interprofessional care of patients with Marcus Gunn pupil.Review the evaluation process of patients with Marcus Gunn pupil.Summarize the relevant history and physical examination of patients with Marcus Gunn pupil.Describe the etiology, epidemiology, and pathogenesis of Marcus Gunn pupil.This activity reviews the evaluation of Marcus Gunn pupil and highlights the role of the interprofessional team in evaluating and treating patients with this condition. To avoid the high morbidity associated with this condition, it must be promptly diagnosed and the cause should be treated. Marcus Gunn pupil is indicative of a defect in the afferent pathway of the light reflex.

Hippus pupil in one eye