The eyelids are mobile protective covers for the eyes formed by
superimposed plates, within which are located certain muscles. The
upper eyelid levator muscle, connected to the third cranial nerve
(oculomotor nerve), is responsible for opening the eyelids, with
the Müller and frontalis muscles giving support. The orbicularis
oculi muscle, connected to the seventh cranial nerve (facial nerve),
performs eye closure, an important function for visual dynamics
Ptosis is a condition of the eyelids that results from an abnormally
low upper eyelid position. It is agreed that the normal position
of the free border of the eyelid is, on average, 2 mm below the
superior corneal limbus; any additional obscuring of the cornea
is considered pathological, in this manner the upper eyelid already
covers 1 to 2 mm of the cornea ().
Ptosis can result from a number of different diseases that can be
grouped into four categories: aponeurotic, mechanical, myogenic
e neurogenic. Aponeurotic causes include senile ptosis, post-ocular
surgery ptosis, blepharochalasia, Graves' disease and pregnancy.
Among mechanical causes we can cite scar-related ptosis and ptosis
associated with tumors. Myasthenia gravis and familial myopathic
progressive ptosis are examples of myogenic ptoses. The most common
neurogenic forms are Horner syndrome, third cranial nerve palsy
(ophthalmoplegia) and synkinetic ptosis ().
Synkinesis is defined as the occurrence of simultaneous movements
or a coordinated sequence of movements of muscles innervated by
different nerves or by different branches of the same nerve ().
In 1883, Marcus Gunn first described synkinesis that progresses
with congenital eyelid ptosis in a peculiar manner, associated with
jaw movement. Since then his finding has been known as Marcus Gunn
Phenomenon. New cases have been described in scientific literature,
but this affliction remains little known, particularly among pediatricians.
The Marcus Gunn Phenomenon (jaw-winking phenomenon) is characterized
by eyelid ptosis, of varying degrees and generally unilateral, which
is reduced, or even transformed into eyelid retraction when the
jaw is moved ().
In general it occurs sporadically although cases of dominant irregular
autosomal heredity have been described ().
The phenomenon is responsible for 2 to 13% of congenital ptoses.
Two recent studies found a prevalence of 5% ().
A five year-old female, otherwise a healthy patient, visited the
pediatrician at the Hospital das Clínicas, Universidade
Federal de Minas Gerais (UFMG) while still a few months old.
The clinical examination was normal with the exception of an ocular
disorder initially believed to be strabismus. This hypothesis was
discarded by the ophthalmologist. The mother reported that, "when
the child stared her eyelid seemed to open more and her head inclined
to one side". The ophthalmologist then directed her to return
when the child was seven months old. At this point, after an ophthalmological
examination, including fundoscopy, it was concluded that the child
did not exhibit strabismus or any other ophthalmological abnormality.
Nevertheless, as the child grew the ocular disorder became more
obvious, causing family anxiety. At three years of age, a third
and later a fourth opinion were sought and astigmatism was detected.
During this period she was examined by several different pediatricians,
because of clinical events and her ptosis was not valued at any
point. At four years of age, on the insistence of the pediatrician
who had looked after the child since birth, she was referred to
the ophthalmologist at the Hospital das Clínicas at
UFMG, who performed a meticulous and complete ophthalmological examination.
During the physical examination, mild right eyelid ptosis could
be seen. Upper right eyelid retraction was also observed, triggered
by chewing and the lateral movements of the mandible (Figure 1).
The patch test, which consists of the occlusion of one eye and observation
of the type and magnitude of eye movement caused by this occlusion,
detected orthotropy. The refraction test demonstrated physiological
childhood hyperopia. Biomicroscopy, an examination that uses a stereomicroscope
along with a slit-lamp allowing the details of both normal and pathological
structures that escape other techniques to be viewed, found no relevant
abnormalities and neither did the fundoscopy. No abnormalities were
detected in the left eye.
Five year-old child with Marcus Gunn Phenomenon on the right
side, mild upper right eyelid ptosis (A). Retraction triggered by
chewing movements and lateral movement of the mandible (B)
According to the clinical case described, a hypothesis of Marcus
Gunn Phenomenon was suggested. Orthoptic examinations were requested
to assess the presence of strabismus. Mild exophoria with foveal
fusion was found. Since in this case ptosis is mild and does not
prejudice visual acuity and there is no strabismus, no surgical
intervention was indicated, just periodic follow-up appointments.
A neurological examination was performed by the neurologist at the
Hospital das Clínicas at UFMG and was normal. Computerized
tomography of the skull was also performed and did not detect any
In Marcus Gunn Phenomenon, elevation and even retraction of the
affected eyelid is triggered by chewing, suction, lateral mandible
movement, smiling, sternocleidomastoid contraction, protruding the
tongue, the Valsalva maneuver and even by simply breathing in ().
In the case described above, mild ptosis was observed and the presence
of eyelid retraction when chewing, opening the mouth or sticking
out the tongue ().
Etiopathogenesis of the phenomenon is not well defined, being attributed
to an anomalous connection between the nerves and the levator and
external pterygoid muscles of the eyelid. In this scenario, the
eyelid levator muscle is innervated by motor ramifications of the
trigeminal nerve and by the oculomotor nerve ().
Recently, a case was described of a child with Marcus Gunn Phenomenon
associated with synkinesis of the extra-ocular, trigeminal and abducent
Some authors have described cases in which there were lesions to
the oculomotor nerve and subsequent innervation of the eyelid by
a ramification of the fifth cranial nerve. Such reports constitute
the rare, acquired form of the phenomenon ().
Some authors claim that the ptosis improves with time, but there
is no scientific proof that this really does take place ().
It is believed that, as time passes, the affected individual will
come to recognize which movements are responsible for the synkinesis
and learn to control or avoid them and so minimize or mask the syndrome.
In the case in question, the child's eyelid ptosis is becoming more
obvious and causing relationship problems with other children.
It should be highlighted that patients who are suspected to have
Marcus Gunn Phenomenon should be quickly referred to ophthalmologists
and neurologists because of the chance of other associated conditions
and secondary complications. Published literature describes the
following possible associated conditions: aponeurosis, unequal focusing,
strabismus, elevator palsy, paralysis of the rectus superior, congenital
nystagmus and congenital fibrosis syndrome ()
Table 1 -
Marcus Gunn Phenomenon associated conditions
(total number of cases found in case reports, case series and literature reviews)
The degree of ptosis can vary and is considered mild when the
eyelid covers 1-2 mm more of the cornea than the 1-2 mm already
covered in a normal state, moderate when it is up to 3 mm, and severe
when equal or greater than 4 mm ().
Careful analysis of the degree of ptosis, its etiology and levator
muscle function define whether surgery is indicated, and also which
surgical approach would be most appropriate. When ptosis is moderate
and esthetically acceptable, surgery is not recommended. Amblyopia
and vertical strabismus, if present, demand surgical eyelid repair.
Patients with severe ptosis and levator muscle dysfunction benefit
from frontalis muscle elevation, associated with myectomy of the
upper eyelid levator. If ptosis is accentuated, but levator muscle
function is preserved, then a simple shortening of the eyelid levator
muscle aponeurosis can be performed ().
In a retrospective analysis of the results of surgical correction
of eyelid ptosis associated with Marcus Gunn Phenomenon it was found
that the degree of ptosis is not, in general, adequately assessed
during conventional ophthalmological examinations. These authors
concluded that surgical results are better when the degree of ptosis
is evaluated preoperatively using the technique of immobilizing
the jaw and temporarily occluding the ipsilateral eye ().
Furthermore, it should be emphasized that the esthetic aspect and
the possibility of developing emotional problems or difficulties
justifies psychological evaluation and, if necessary, additional
Other synkinetic abnormalities which may be associated with eyelid
ptosis are Inverted Marcus Gunn Phenomenon and Marin-Amat syndrome
Both conditions progress with ptosis that becomes more obvious when
the mandible is moved. Initially they were believed to be the same
disease, but recent studies have found differences between them.
The first is a congenital condition in which the eyelid levator
muscle is inhibited. Marin-Amat syndrome is acquired, occurring
after facial paralysis and in this case orbicularis oculi and levator
muscle function is not compromised ().
Neurological and ophthalmological examination is fundamental to
the differentiation of the various types of ptosis. Sudden manifestation
of eyelid ptosis, for example, is suggestive of myasthenia gravis.
An association between ptosis and homolateral ipslateral myosis
implies a possibility of Horner's syndrome ().
This case report was carried out with the objective of alerting
pediatricians to the existence of the Marcus Gunn Phenomenon, which
remains little known. It is usual to recommend a routine ophthalmological
examination as the child reaches three to four years of age and
when a certain degree of cooperation can be expected. The pediatrician
is in frequent contact with the child from birth throughout the
period of rapid growth development and, therefore, has an essential
role in detecting ophthalmological abnormalities, such as strabismus,
blindness, tumors and others, such as the Marcus Gunn Phenomenon