Marcus Gun Jaw Wink
Marcus Gunn Jaw wink ptosis is an example of an abnormal innervation connecting two groups of normally UNRELATED muscles. It does not generally improve with time, but children do tend to learn how to minimize the appearance. The phenomenon is thought to be due to a congenital misdirection of the fifth cranial nerve fibers into a branch of the third cranial nerve that supplies levator muscle.
- This causes the eyelid to open (increase in the palbebral fissure) with movements of the mouth higher position of the ptotic eyelid on downgaze.
- Children with significant ptosis could need to tilt their head back into a chin-up position, lift their eyelid with a finger, or raise their eyebrows in an effort to see from under their drooping eyelid(s).
- Marcus Gunn Jaw-wink ptosis does not generally improve with time, but children do tend to learn how to minimize the appearance.
- While the cause of Congenital ptosis is often unclear, the most common reason is improper development of the levator muscle. The levator muscle is the major muscle responsible for elevating the upper eyelid.
- Children with Congenital ptosis could also have amblyopia (“lazy eye”), strabismus (eyes that are not perfectly aligned or straight), refractive errors, astigmatism, or blurred vision. Drooping of the eyelid could lead to in an undesired facial appearance.
Evaluation of the Patient
Complete ophthalmic exam with particular attention to visual acuity is necessary. Considerations are as follows:
- In a series of Congenital ptosis cases incidence of amblyopia was measured to be 20% of which 3% was attributable to droopy eyelid.
- In the past, the chin elevation posturing was considered a sign of fusion and, thus, indicating a low risk for amblyopia.
- It has recently been shown that the chin elevation does not rule out the presence of significant amblyopia.
- Thorough motility examination is essential.
- In a series of 113 patients, 31% were found to have strabismus and of these, 3% of the cases were believed to be caused by ptosis that disrupted binocular fusion.
- Because the superior rectus is often involved, full extraocular motion needs to be carefully evaluated.
Concurrent Anatomic Abnormalitites
- Physiologic defects such as jaw-winking ptosis could require transection of the levator muscle as well as frontal-is suspension.
- Because of the levator aponeurosis resection, children require general anesthesia – a formula is used to determine the amount of levator aponeurosis resection.
Marcus-Gunn Jaw-winking Ptosis
- In 1883 Marcus Gunn reported an unusual type of congenital ptosis with with a peculiar associated movement of the affected lid. Previous authors have reported Marcus-Gunn phenomena to occur in 2 to 13% of patients with congenital ptosis.
- The phenomenon is thought to be due to a congenital misdirection of the fifth cranial nerve fibers into a branch of the third cranial nerve that supplies levator muscle.
- Patients are classified according to the degree of two parameters: a 3 x 3 matrix is constructed which gives 9 combinations of ptosis (mild, moderate, severe) in jaw-winking (mild, moderate, severe). Different positions of the matrix correspond to one of several operations which are abdicated for the correction of this defect.
- Beard reported 76% of his patients with Marcus-Gunn syndrome had an associated weakness of the superior rectus.
- Incidence of amblyopia in patients with Marcus-Gunn jaw-winking ptosis is reported to be approximately 35%.
- In a study in 1984 of 64 patients with jaw- winking ptosis, 60% were found to have amblyopia, 60% were found to have strabismus and 25% were found to have anisometropia. Twenty-five percent were found to have a double elevator palsy.
- It has been proposed that the Marcus-Gunn phenomena is secondary to supranuclear etiology. The prevalence of double elevator palsy in this study tends to support the theory of a supranuclear lesion. In this study of 1984, of 71 patients followed for approximately 5 years, they were unable to document any objective improvement in any of their patients1 However, they felt that adults were able to control their lid position in excursion of masquerading their jaw-winking phenomena.
- In general, if the visual axes are not obscured by the ptotic lid, it is best to defer treatment until the child is age 3 or 4.
- The surgical procedure is determined by the amount of levator function present and the severity of ptosis. Function is typically categorized as poor (less than 4 mm), fear (5 to 7 mm) and good (more than 8 mm). In cases of severe ptosis in less than 2 mm of levator function, suspension of the lid to frontalis muscle is the procedure of choice. Congenital ptosis is treated surgically, with the specific operation based on the severity of the ptosis and the strength of the levator muscle.
- Conjunctival-muellers resection
- Levator resection
- Frontalis sling: silicone, fascia (autogenous or donor), supra-mid
- If the ptosis is not severe, surgery is generally performed when the child is between 3 and 5 years of age (the “pre-school” years).
- When the ptosis interferes with the child’s vision, surgery is performed at an earlier age to allow proper visual development.
- Congenital ptosis is most often treated by ophthalmic plastic and reconstructive surgeons who specialize in disease and conditions affecting the eyelids, lacrimal (tear) system, the orbit (bone cavity around the eye), and adjacent facial structures.