In 1883, Marcus Gunn described a 15-year-old girl with a peculiar type of congenital ptosis that included an associated winking motion of the affected eyelid on the movement of the jaw. This synkinetic jaw-winking phenomenon now bears his name. See the image below.
Congenital left upper eyelid ptosis.
Patients with Marcus Gunn jaw-winking syndrome have variable degrees of blepharoptosis in the resting, primary position. Although Marcus Gunn jaw-winking syndrome is usually unilateral, it can present bilaterally in rare cases.
The wink reflex consists of a momentary upper eyelid retraction or elevation to an equal or higher level than the normal fellow eyelid upon stimulation of the ipsilateral pterygoid muscle. This response is followed by a rapid return to a lower position. The amplitude of the wink tends to be worse in downgaze. This rapid, abnormal motion of the eyelid can be the most disturbing aspect of the jaw-winking syndrome.
The wink phenomenon may be elicited by opening the mouth, thrusting the jaw to the contralateral side, jaw protrusion, chewing, smiling, or sucking.[2, 3, 4, 5] This wink phenomenon is often discovered early, as the infant is bottle-feeding or breastfeeding. See the image below.
Marcus Gunn jaw-winking with left upper eyelid retraction on opening of the mouth.
Jaw-winking ptosis is almost always sporadic, but familial cases with an irregular autosomal dominant inheritance pattern have been reported.
Marcus Gunn jaw-winking is thought to be a form of synkinetic ptosis. An aberrant connection appears to exist between the motor branches of the trigeminal nerve (CN V3) innervating the external pterygoid muscle and the fibers of the superior division of the oculomotor nerve (CN III) that innervate the levator superioris muscle of the upper eyelid.[7, 8, 9, 10]
Electromyographic studies demonstrate this synkinetic innervation by showing simultaneous contraction of the external pterygoid and levator muscle. In rare cases, synkinesis may be present between the internal pterygoid and levator muscles. In these cases, the eyelid elevates on closing the mouth and clenching the teeth.
A few authors have speculated that the jaw-winking is not due to a new aberrant pathway, but rather the disinhibition of preexisting phylogenetically more primitive mechanisms. This is thought to explain why individuals who are not affected will often open their mouths while attempting to widely open their eyes to place eye drops or to apply makeup.
Since jaw-winking ptosis is believed by most to be due to abnormal innervation of the levator muscle and not secondary to myopathic changes, it is not surprising that most histopathologic studies have revealed normal striated muscle.
One study found variable degrees of fibrosis within the affected levator muscle and to a lesser degree in the muscle of the normal, nonptotic eyelid.
Approximately 50% of blepharoptosis cases are congenital. Incidence of Marcus Gunn jaw-winking syndrome among this population is approximately 5%.
Marcus Gunn jaw-winking syndrome is associated with strabismus in 50-60% of cases. Superior rectus palsy is found in 25% of cases, and double elevator palsy is found in another 25% of cases. In double elevator palsy, a deficiency in elevation of the globe occurs in all positions of gaze, secondary to an apparent weakness of the superior rectus and inferior oblique muscles. On rare occasions, horizontal strabismus in the absence of a vertical motility disturbance may occur.
Incidence of anisometropia among patients with Marcus Gunn jaw-winking syndrome is reported to be 5-25%. Anisometropia exists when a refractive difference between the 2 eyes of 1.25 diopters of sphere or 1 diopter of cylinder is present.
Amblyopia occurs in 30-60% of patients with Marcus Gunn jaw-winking syndrome and is almost always secondary to strabismus or anisometropia, and, only rarely, is due to occlusion by a ptotic eyelid. Amblyopia usually is defined as a decrease in vision of 2 or more lines on the Snellen chart.
No known racial predilection exists.
Early reports showed jaw-winking ptosis to be more prevalent in females than in males; however, larger case series have shown an equal prevalence among males and females.[2, 14]
Marcus Gunn jaw-winking syndrome is usually evident at birth. The winking phenomenon is often first noted by the parents when the infant is feeding.
It has been suggested, and older patients often claim, that the jaw-winking improves over time; however, it has not proven to be true on objective evaluation. More likely, patients stop seeking care as they get older, or they learn to compensate for and mask the wink response.[2, 7, 14, 15]
Likewise, the degree of ptosis may be underestimated with the patient able to adjust the height with varying jaw positions. This is referred to by some as "habitual" ptosis.
As with any patient who requires eyelid surgery, first address associated strabismus.
Superior rectus palsy
Superior rectus palsy can be corrected by resecting the superior rectus muscle but only in the absence of inferior rectus restriction.
Since the superior rectus is loosely bound to the overlying levator, the upper eyelid will be pulled inferiorly during resection, exacerbating any ptosis already present. This can be addressed during the subsequent ptosis repair.
Double elevator palsy
Double elevator palsy manifests as a deficit in the elevation of the globe in all fields of gaze.
It may be the result of superior rectus and inferior oblique palsy and/or inferior rectus restriction.
Inferior rectus restriction may be suggested by the following:
Positive forced ductions in elevation
Normal force generations in upgaze indicating an absence of superior rectus or inferior oblique palsy
Poor or absent Bell phenomenon on the affected side
Inferior rectus restriction is treated by recession of the inferior rectus muscle.
A combined superior rectus and inferior oblique (double elevator) palsy requires a transposition procedure to displace the medial and lateral recti muscles superiorly (Knapp procedure).
Consider eyelid surgery only when the parents (or the patient) and the surgeon agree about whether the most cosmetically objectionable condition is the ptosis or the jaw-winking or whether it is a combination of both.
Many techniques are described for the correction of jaw-winking ptosis, reflecting the ongoing controversy regarding the surgical management of this condition.
If the jaw-winking is cosmetically insignificant, it can be ignored in the treatment of the ptosis.
If the ptosis is mild, the patient may elect not to proceed with surgery. If correction is desired, perform a Müller muscle and conjunctival resection (MMCR), a Fasanella-Servat procedure, or a standard external levator resection.[7, 19]
If the ptosis is moderate to severe, a levator resection may be indicated. Beard advocated performing more resection than normal to avoid undercorrection.
In severe ptosis, a supermaximum (>30 mm) levator resection or frontalis suspension is necessary.
Although the amount of ptosis and synkinetic eyelid movement is variable, those patients with more severe ptosis tend to have the worse aberrant upper eyelid movement.
The jaw-wink is considered cosmetically significant if it is 2 mm or more.
Any attempt to repair the ptosis without addressing the jaw-winking would result in an exaggeration of the aberrant eyelid movement to a level well above the superior corneal limbus, which would be unacceptable to the patient.
If the jaw-wink is significant, ablation of the levator and resuspension of the eyelid to the brow are necessary. Several techniques have been suggested to obliterate levator function, which effectively dampens the aberrant eyelid movement.
Bullock advocated complete excision of the levator aponeurosis and muscle all the way to the orbital apex.
Dillman and Anderson argued that removal of a portion of the levator muscle above the Whitnall ligament (ie, myectomy) is adequate to obliterate its function without extensive dissection and damage to eyelid structures.
Bowyer and Sullivan describe the removal of a portion of levator muscle above the Whitnall ligament through a posterior conjunctival approach.
Dryden et al proposed suturing the transected levator aponeurosis to the arcus marginalis of the superior orbital rim. This technique not only effectively deactivates the muscle but also allows the procedure to be reversed, if necessary.
Beard and others have advocated bilateral excision of the levator muscle and bilateral frontalis suspension. While this approach almost completely eliminates the wink and arguably results in better symmetry, it is often difficult to persuade the parents and the patient to perform surgery on and effectively damage the normal contralateral levator muscle.
Satisfactory and predictable results also can be obtained after only unilateral levator excision on the affected side, combined with bilateral frontalis suspension. This leaves the normal functioning levator muscle to elevate the nonptotic eyelid in primary position but produces a lag in downgaze for improved symmetry.
Kersten et al advocate unilateral levator muscle excision and frontalis sling only on the affected side. If the postoperative result is judged to be unsatisfactory, the parents or the patient can opt for further surgery to the contralateral side. Any amblyopia and strabismus should first be addressed, as there may be insufficient drive to lift the disinserted eyelid.
Islam et al described a technique of dissecting a frontalis flap hinged superiorly through a suprabrow incision that is then brought down into an eyelid crease incision. The frontalis flap is used to suspend the ptotic eyelid after extirpation of the levator muscle.
Lemagne and Neuhaus described techniques that involve transection of the involved levator followed by transposition of the distal segment to the brow, which effectively suspends the eyelid to the frontalis muscle.[25, 26] Their techniques maintain normal eyelid contour, as the levator aponeurotic attachments are left undisturbed.