Marcus Gunn

Marcus Gunn phenomenon is a condition where a person’s eyelid droops or lifts abnormally when they move their jaw or chew. It’s a type of jaw-winking synkinesis that occurs because certain nerves controlling eye and jaw muscles are connected in a way that causes this movement. Often associated with congenital eyelid ptosis (drooping eyelid), it results in the eyelid elevation during jaw movements like opening the mouth or chewing. The severity varies, and it’s usually present from birth. Treatment may involve surgery if the drooping affects vision or appearance significantly.