Pseudoptosis

Pseudoptosis encompasses conditions such as brow ptosis and laxity and dermatochalasis that mimic true ptosis. Pseudoptosis can also be caused by microphthalmos or by phthisis bulbi, conditions resulting in the eyelids being inadequately supported by the globe. Hypotropia also causes pseudoptosis, because the perception of eyelid position is related to the position of the eye (see Fig 11-2). Contralateral lid retraction may also give rise to pseudoptosis.

Apraxia of Eyelid Opening

Apraxia of eyelid opening is a rare disorder causing unilateral or bilateral ptosis. Thought to be supranuclear in origin, it is characterized by the inability to voluntarily open the eyelids, associated with frontalis contraction and facial grimacing. It is often associated with extrapyramidal disease such as Parkinson disease, multiple system atrophy, Huntington disease, Wilson disease, and progressive supranuclear palsy. The disorder has also occurred after bilateral frontal lobe infarcts. Apraxia of eyelid opening may also occur in patients with essential blepharospasm.

Tozlovanu V, Forget R, Iancu A, Boghen D. Prolonged orbicularis oculi activity: a major factor in apraxia of lid opening. Neurology. 2001;57(6):1013–1018.

Eyelid Retraction

Eyelid retraction is present if, with the eyes in primary position, the sclera is visible above the superior corneal limbus. It is usually acquired but may be present at birth. Preterm infants occasionally have a benign transient conjugate downgaze associated with upper eyelid retraction. This finding is thought to be caused by immature myelination of the vertical eye-movement system and immaturity or dysfunction of the extrageniculocalcarine visual pathways. Many normal infants (80% of children 14–18 weeks of age) have an eye-popping reflex when ambient lighting levels are reduced.

Causes of acquired eyelid retraction are listed in Table 11-2. The most common cause in adults is thyroid eye disease (see Fig 11-4). The eyelid retraction (Collier sign) in dorsal midbrain syndrome (see Chapter 7, Fig 7-5) is a less common cause. Unilateral eyelid retraction as a result of contralateral ptosis may occur in patients with levator aponeurotic defects; this phenomenon results from Hering’s law of equal innervation. Bilateral eyelid retraction can be associated with thyroid eye disease, familial periodic paralysis, Cushing syndrome, and midbrain disease, or hydrocephalus with vertical nystagmus. Unilateral eyelid retraction is caused chiefly by thyroid eye disease but may also occur from aberrant regeneration of the third nerve (see Chapter 8), Marcus Gunn jaw-winking syndrome (see Fig 11-6), idiopathic levator fibrosis, and carcinomatous infiltration. Subconjunctival or transcutaneous injections of botulinum toxin and several surgical procedures have been used to reduce the degree of eyelid retraction in patients with thyroid eye disease.

Table 11-2

Figure 11-7 Distribution of seventh nerve and topical diagnosis of lesions.

1.Supranuclear facial palsy: contralateral weakness of lower two-thirds of the face with

some weakness of the orbicularis oculi; retained expression

2. Nuclear facial palsy: facial monoplegia (congenital) plus sixth nerve nucleus involvement (ipsilateral gaze palsy) and frequent ataxia, occasional Horner syndrome

Peripheral lesions result in facial monoplegia including the orbicularis oculi and frontalis muscles, plus:

3. Cerebellopontine angle: decreased tearing, dysgeusia, loss of salivary secretion, loss of taste from anterior two-thirds of tongue, hearing impairment, nystagmus, vertigo, ataxia,

and adjacent cranial nerve (CN V, CN VI) findings

4.Geniculate ganglionitis (Ramsay Hunt syndrome, zoster oticus): same findings except

without involvement of brainstem and other cranial nerves

5.Isolated ipsilateral tear deficiency due to involvement of vidian nerve or sphenopalatine ganglion (accompanying sixth nerve palsy with cavernous sinus involvement)

6.Fallopian canal: involvement of nerve to stapedius muscle, dysacusis, involvement of

chorda tympani, loss of taste to anterior two-thirds of tongue, impaired salivary secretion 7. Distal to chorda tympani: isolated paralysis of facial muscles

8. Distal to branching of seventh nerve after it leaves stylomastoid foramen: only certain

branches of seventh nerve are affected (localized facial; in addition, bilateral seventh nerve palsy may result from weakness)

In addition, bilateral seventh nerve palsy may result from congenital conditions (Möbius syndrome), sarcoidosis, Guillain-Barré syndrome, or neurofibromatosis type 2 (bilateral acoustic neuromas). GSPN = greater superficial petrosal nerve.

Kline LB, Bajandas FJ. Neuro-Ophthalmology Review Manual. 5th ed. Thorofare, NewJersey: Slack; 2000.)

Any aberrant facial movements at rest or during volitional movement should be noted (Fig 11-8). After any facial neuropathy, but most commonly as a result of Bell palsy, regenerating axons may reinnervate different muscles from those originally served; such aberrant regeneration can cause synkinetic movements. In this situation, the involved facial muscles may remain weak. When axons originally destined for the orbicularis oculi reinnervate the lower facial muscles, each blink may cause a twitch of the corner of the mouth or a dimpling of the chin. Conversely, movements of the lower face—such as pursing the lips, smiling, or chewing with the mouth closed—may produce involuntary eyelid closure.

Figure 11-8 Facial nerve synkinesis. Misdirection may occur with recovery of seventh nerve function after trauma or surgery. A, In this 54-year-old patient, aberrant regeneration of the left seventh nerve after resection of a cerebellopontine angle meningioma caused eyelid closure when she attempted to smile (B). (Courtesy of Steven A. Newman, MD.)

Other disorders of aberrant facial innervation include lacrimation caused by chewing (crocodile