Some people have a drooping upper eyelid that lifts on its own when the jaw moves. Not from a tic, not from effort, but as a fixed reflex tied to chewing, sucking, smiling, or pushing the jaw sideways. The lid jumps upward, sometimes higher than the unaffected one, then drops back.
A case report published in January in the International Journal of Medicine in Developing Countries is the latest to document the phenomenon, noting that it is classically elicited by voluntary jaw movements such as opening the mouth or moving the jaw sideways. The diagnosis is Marcus Gunn jaw-winking syndrome, and what makes it worth a reader's attention is less the wink itself than what occasionally comes with it.
Two Nerves That Were Never Supposed to Meet
The eyelid is raised by the levator palpebrae superioris, a muscle supplied by the superior division of the oculomotor nerve, the third cranial nerve. Chewing is driven by the pterygoid muscles, supplied by the mandibular division of the trigeminal nerve, the fifth.
In Marcus Gunn jaw-winking, a branch that should have gone to the pterygoid muscle ends up connected to the levator instead. Every signal sent to chew is also delivered to the eyelid.
According to StatPearls, the syndrome sits in a group called congenital cranial dysinnervation disorders. It occurs in roughly 2% to 13% of people with congenital ptosis, affects men and women about equally, and is usually confined to one side. It has been recognized since 1883, when the Scottish ophthalmologist Robert Marcus Gunn described a 15-year-old girl whose eyelid moved with her jaw.
Most cases are caught in infancy, because the movement is obvious while a baby feeds. A 2025 report described a 5-month-old girl whose left eyelid rose during suckling, with no other abnormality found.
The Eye Finding That Points Somewhere Else Entirely
Within the eye, the associations are well characterized. Published series put strabismus at 50% to 60% of cases, anisometropia at 5% to 25%, and amblyopia at 30% to 60%. Amblyopia can follow from strabismus, from unequal refraction, or from the drooping lid itself blocking vision.
Ophthalmologists have also documented co-occurrence with monocular elevation deficiency, the most common type of strabismus seen alongside the syndrome, reported in 25% to 48% of patients. A 2025 case in Cureus described a 14-year-old boy with both, and argued the two may be phenotypic variations of the same developmental disorder.
The associations outside the eye are the ones more likely to be missed. StatPearls lists CHARGE syndrome among the recognized systemic associations, alongside cleft lip and palate, olfactory nerve disturbance, and renal calculi. The C, H, A, R, G and E stand for coloboma, heart defects, choanal atresia, retardation of growth and development, genital abnormalities and ear abnormalities. Choanal atresia is a congenital blockage at the back of a nasal passage.
That link has prompted a specific recommendation in the ear, nose and throat literature: every patient diagnosed with the jaw-winking phenomenon should be assessed by an ENT specialist to rule out choanal atresia, ear anomalies and hearing loss. It is not a common pairing, and most people with the wink have nothing else. But an eye examination will not find any of it.
Surgery Is a Decision, Not a Default
Treatment is not automatic. The wink often becomes less noticeable with age, and the first priority is vision rather than appearance. Any amblyopia or strabismus gets addressed before anyone considers operating on the lid.
When surgery is chosen, the standard approach is counterintuitive. Because the synkinesis travels along the levator muscle's aberrant nerve supply, surgeons disconnect or remove that muscle and then suspend the eyelid from the forehead muscle instead. A retrospective series of 42 patients published in the Journal of Ophthalmology reported that jaw winking resolved in all 34 operated patients with good correction of the ptosis. The same analysis found that the severity of the preoperative wink independently predicts residual synkinesis afterward, with severe cases carrying roughly 18 times the risk compared with moderate ones.
Some surgeons operate on both eyelids to avoid asymmetry, since taking the levator out of one lid changes how the two match.
What the Wink Does and Does Not Mean
A striking wink does not mean anything is wrong beyond the eyelid. Plenty of people have the isolated phenomenon and nothing else.
Some do not even have the droop. A case series in the Indian Journal of Ophthalmology identified 14 patients out of 207 with the jaw-winking phenomenon and no blepharoptosis at all, at a mean age of presentation of 9.5 years. In that group, the wink was mild in every case, which is a plausible reason the condition goes unnamed in adults for decades.
The useful takeaway is a referral habit rather than an alarm. An eyelid that moves with the jaw is a visible marker of a developmental error in cranial nerve wiring, and that error occasionally has company. A comprehensive ophthalmologic evaluation catches the strabismus and refractive problems that actually threaten sight. An ENT assessment covers the nasal, ear, and hearing anomalies the eye examination will not.
For adults who have lived with it since childhood without ever having it named, that is worth raising at the next appointment rather than treating as a quirk.
Key Questions Answered
What is Marcus Gunn jaw-winking syndrome?
A congenital condition in which a branch of the trigeminal nerve, which drives chewing, is misconnected to the nerve that lifts the upper eyelid. Jaw movement therefore raises the drooping lid.
How common is it?
It accounts for roughly 2% to 13% of congenital ptosis cases. It is usually one-sided and affects men and women about equally.
What sets off the wink?
Opening the mouth, thrusting the jaw to the side, jaw protrusion, chewing, smiling, or sucking can all trigger it.
Is it linked to other conditions?
Within the eye, strabismus, unequal refraction, and amblyopia are common. Reported systemic associations include CHARGE syndrome, which features choanal atresia, as well as cleft lip and palate and olfactory nerve disturbance.
Does it need treatment?
Not always. The wink often becomes less noticeable with age. Vision problems such as amblyopia and strabismus are treated first, and eyelid surgery is considered separately.
What does the surgery involve?
Typically disconnecting or removing the levator muscle, which carries the faulty nerve supply, and suspending the eyelid from the forehead muscle. Severe preoperative winking raises the chance of residual movement afterward.
When should an adult with this get it checked?
At any point. A full ophthalmologic evaluation addresses the vision risks, and an ENT assessment can look for the nasal, ear, and hearing anomalies that sometimes accompany the condition.
