3.4 CCDD

Question 1

What is Moebius syndrome?

Answer 1

Congenital, uni or bilateral, nonprogressive facial weakness and limited abduction of the eye(s). A rare disease which can be associated with other CN palsies, orofacial abnormalities, and limb defects.

Question 2

What is the cause of Moebius syndrome?

Answer 2

Cause is unknown, thought to be related to disruption of development in CN VI and VII and that the embryo grows in the womb or from a hypoxic or traumatic insult to the developing brain.

Question 3

List some symptoms of Moebius syndrome

Answer 3

o Visual symptoms
 Corneal erosion (due to inability to blink) and sensitivity to light (due to inability to squint)
 Absence of lateral eye movement, because this movement is controlled by cranial nerve VI, a head turn posture may be used
 Strabismus
o Problems with feeding, swallowing and choking – inability to suck, this can be an early indication when nursing an infant with Moebius syndrome and excessive drooling.
o Speech difficulties (due to impairment of lip function, reduced tongue function, cleft palate and reduced soft palate mobility).
o Frequent ear infections if VIII CN is affected.
o Dental problems – teeth may be missing or overcrowded due to small size of the lower jaw.
o Low muscle tone (hypotonia)
o psychological problems, particularly as the lack of facial expression can sometimes incorrectly be assumed by others to be due to unfriendliness or lack of intelligence.

Question 4

What are non surgical management options of Moebius syndrome?

Answer 4

 Correction of refractive errors
 Restoration of VA including management of any strabismic amblyopia
 Ocular treatment – lagophthalmos can result in exposure keratitis which may require ocular lubricants and taping of eye lids at night.

Question 5

What are the surgical management options for Moebius syndrome?

Answer 5

 Strabismus surgery to improve esotropia, large medial rectus recessions

Question 6

Name differential diagnosis for Moebius syndrome

Answer 6

o Lack of facial expression is also seen in infantile muscular dystrophy and facioscapulohumeral dystrophy
o Duane’s syndrome
o Infantile esotropia
o Ocular motor apraxia
o Isolated horizontal gaze palsy.

Question 7

What is the Marcus Gunn Winking Phenomenon?

Answer 7

a unilateral blepharoptosis with upper eyelid contraction with the contraction of the pterygoid muscle.

Question 8

What are the classifications for Marcus Gunn?

Answer 8

o Mild (less than 2mm)
o Moderate (2-5mm)
o Severe (more than 5mm

Question 9

What are features of Marcus Gunn?

Answer 9

Partial ptosis in PP
o Amplitude of wink tends to worsen in downgaze
o In some patients a limitation on upgaze on affected side is present – double elevator palsy. This results in hypophoria or in some cases a hypotropia.
o Superior rectus palsy can also be associated
o Anisometropia can be associated
o Amblyopia can occur as a result of the strabismus or anisometropia, and less commonly as a result of stimulus deprivation due to the ptosis.

Question 10

What is the aetiology of Marcus Gunn?

Answer 10

o Thought to occur due to a neural misdirection of the superior division of the 3rd (oculomotor) and the motor branches of the 5th (trigeminal) cranial nerves.
o Familial cases appear to be extremely rare.
o Some reports of acquired Marcus Gunn jaw winking phenomenon following trauma or ocular surgery.

Question 11

How is Marcus Gunn diagnosed?

Answer 11

o Unilateral blepharoptosis
o Upper eyelid movement is seen on opening the mouth, movement of the jaw to the contralateral side, chewing, sucking, swallowing, clenching teeth, and protrusion of the jaw.
o Hypotropia on the affected side may be present with the cover test due to associated superior rectus palsy
o Mostly seen on chewing or sucking, so usually noticed by parents at a very young age
o Useful to ask children who are old enough to open their mouth wide in clinic, or to give them a sweet to suck or younger children a bottle to observe the lid position.

Question 12

List some differentials for Marcus Gunn

Answer 12

o Inverse Marcus Gunn phenomenon – ptosis lessens when mouth opened and jaw moved to affected side
o Marin-Amat syndrome – both eyes close momentarily with mouth opening.
o Chronic progressive external ophthalmoplegia
o Congenital fibrosis syndrome
o Myasthenia gravis

Question 13

What are management options for Marcus Gunn?

Answer 13

o Refractive correction for any anisometropia
o Patching for any amblyopia
o Most patients learn to disguise the wink with time – they learn which position worsens the wink
o In severe cases surgery may be considered:
 Where cosmesis of ptosis/winking is poor
 It is important to correct any strabismus first as this can alter the lid position.

Question 14

How would a SR palsy present?

Answer 14

• Can consider SR resection provided there is no IR restriction
• SR resection can pull the upper eyelid inferiorly as it is bound to the levator, so can exacerbate any ptosis present. This can be reflected with a ptosis repair.

Question 15

How would a double elevator palsy present?

Answer 15

• Combined SR and IO palsy – requires transposition of medial and lateral recti superiorly (Knapp).

Question 16

Why would we perform eyelid surgery in Marcus Gunn?

Answer 16

• Many techniques described, reflecting the ongoing controversy
• If the jaw-wink is significant and the ptosis is moderate to severe, a resection of the levator palpebrae superioris muscle with bilateral frontalis suspension could be considered.
• Some surgeons suggest bilateral disinsertion of the levator muscles and bilateral brow suspension.