Marcus Gunn Pupil, also known as the Marcus Gunn phenomenon or jaw-winking syndrome, is a medical condition characterized by an abnormal response of the pupil of the eye to a change in light intensity. It is named after the Scottish ophthalmologist Robert Marcus Gunn, who first described the condition in 1883.
In a person with Marcus Gunn Pupil, the affected eye's pupil exhibits a significant dilation or constriction when the person opens or closes their mouth, respectively, while the other eye's pupil does not show any unusual response. This abnormal pupillary response occurs due to a miswiring of the nerves that control the muscles responsible for pupil contraction or dilation.
The exact cause of Marcus Gunn Pupil is not fully understood, but it is believed to result from a congenital defect in the development of the cranial nerves responsible for eye and facial movements. In most cases, the condition is not associated with any other underlying medical or neurological issue.
Marcus Gunn Pupil is typically harmless and does not cause any vision problems or discomfort. Due to its benign nature, treatment is usually unnecessary. However, in rare cases where the abnormal pupillary response is severe and affects the person's daily life or social interactions, surgical correction may be considered.
Overall, Marcus Gunn Pupil is a rare eye condition characterized by an aberrant pupillary response to jaw movements, which can be observed through a dilation or constriction of the affected eye's pupil.
