ABSTRACT
The authors present a case of Marcus Gunn Syndrome, whose major feature is the synkinetic movement between mastication muscles and the upper eyelid, present in five per cent of the cases of congenital blepharoptosis. In the case presented, the synkinesia was observed between the left lateral ptreygoid and the upper right eyelid. The etiology of the Marcus Gunn phenomenon is not known and treatment is mainly aimed at the palpebral ptosis, when it is severe, by resecting or transposing the levator muscle and correcting other extra-ocular lesions, such as strabismus, amblyopia, anisometropia and other conditions detected by specialized examination. The diagnosis is generally made early by the child's parents or guardians who observe the synkinetic movement while nursing feeding the infant. The assisting physician, or specialist, guides the treatment, mainly in relation to the indication or occasion for correcting major lesions. It is noteworthy to point out that the correction of the palpebral ptosis should, whenever possible, be accompanied by surgery of the palpebral levator in order to avoid the even more exaggerated permanence of the palpebral synkinesia.