References

1.How is ptosis classified?

Ptosis is classified by either time of onset or etiology. By onset, ptosis is either congenital or acquired. By etiology, ptosis may be neurogenic, aponeurotic, mechanical, myogenic, or traumatic.

2.What is the most common cause of acquired ptosis?

Acquired ptosis is most often the result of disinsertion or attenuation of the levator aponeurosis, which is most commonly related to aging but can be related to chronic ocular inflammation or eyelid edema (Fig. 37-1).

3.What clinical findings help to differentiate congenital ptosis from acquired aponeurotic ptosis?

Patients with aponeurotic ptosis have a ptotic eyelid in all positions of gaze. In downgaze the ptotic eyelid remains ptotic. Patients with congenital ptosis, however, demonstrate eyelid lag in downgaze. The ptotic eyelid frequently appears higher than the normal eyelid as the patient moves toward downgaze. This is caused by the maldevelopment of the levator muscle, with poor ability to contract in elevation as well as inability to relax as the eyelid moves to downgaze.

KEY POINTS: FEATURES OF APONEUROTIC PTOSIS

1. High eyelid crease (>10 mm)

2. Moderate ptosis (3-4 mm)

3. Good levator function (>10 mm)

4. No eyelid lag on downgaze

4.What are the features of congenital ptosis?

Congenital ptosis is caused by a dystrophy or maldevelopment in the levator muscle/superior rectus complex (Fig. 37-2). Most patients demonstrate poor levator function on examination and, at surgery, have fatty infiltration of the levator muscle. This myogenic abnormality causes an inability of the levator to relax on downgaze, resulting in eyelid lag and in some cases, lagophthalmos. Patients may or may not demonstrate motility defects because of superior rectus dysfunction (double elevator palsy with ptosis, vertical strabismus, and poor Bell’s phenomenon). Approximately 75% of cases are unilateral.

With congenital ptosis, it is critical to evaluate visual function and refractive error as amblyopia will occur in up to 20% of cases.1

5.What causes pseudoptosis?

Causes of pseudoptosis (Fig. 37-3) include the following:

•Hypotropia on the ptotic side

•Eyelid retraction on the opposite side

•Enophthalmos/phthisis bulbi

•Anophthalmos/microphthalmos

•Severe dermatochalasis—with skin obscuring the position of the eyelid margin

6.What is the primary cause of ptosis after intraocular surgery?

It is thought that levator dehiscence causes ptosis related to previous intraocular surgery. The exact etiology is uncertain; however, it has been linked to superior rectus bridal sutures, eyelid speculums, retrobulbar and peribulbar injections, and other draping maneuvers associated with manipulation of the eyelids. Affected patients probably had a tendency toward levator dehiscence preoperatively.

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Figure 37-1.  Involutional (aponeurotic) ptosis is characteristically mild to moderate with high upper eyelid crease. Deep sulci are seen in severe cases. Levator function is essentially normal. (From Kanski JJ: Clinical Ophthalmology: A Synopsis. New York, Butterworth-Heinemann, 2004.)

A

B

C

Figure 37-2.  Simple congenital ptosis. A, Decreased levator muscle function occurs along with an indistinct upper eyelid crease. B, The ptosis is exaggerated in upgaze because of the poor function of the levator muscle. C, In downgaze the ptosis is reduced or absent because the fibrotic levator muscle cannot stretch. (From Custer PL: Blepharoptosis. In Yanoff M, Duker JS [eds]: Ophthalmology, ed 2, St. Louis, Mosby, 2004.)

Figure 37-3.  Left pseudoptosis caused by ipsilateral hypotropia. (Kanski JJ: Clinical Ophthalmology: A Systematic Approach, ed 5, New York, Butterworth-Heinemann, 2003.)

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7.What is the anatomic cause for the eyelid crease?

The eyelid crease is formed by the levator aponeurotic attachments that travel through the orbicularis muscle to the skin. With aponeurotic ptosis, these attachments are disinserted, causing the eyelid crease to elevate.

8.What neurologic conditions are associated with ptosis?

Neurologic conditions that must be considered in a ptosis evaluation include third-nerve palsy, Horner’s syndrome, myasthenia gravis, Marcus Gunn’s jaw-winking syndrome, ophthalmoplegic migraine, multiple sclerosis, and the Miller-Fisher syndrome, a variant of Guillain-Barre syndrome.

KEY POINTS: FEATURES OF THIRD-NERVE PALSY

1. Ptosis—mild to complete

2. Decreased elevation, adduction, and depression—may not all be present, depending on superior or inferior division involvement

3. Possible ipsilateral pupillary dilation—may be subtle to complete

9.What are the myogenic causes of ptosis?

Muscular abnormalities associated with ptosis include myasthenia gravis, muscular dystrophies, chronic progressive external ophthalmoplegia (CPEO), oculopharyngeal dystrophy, and congenital maldevelopment of the levator.

KEY POINTS: FEATURES OF CPEO

1.Slowly progressive ophthalmoplegia

2.Bilateral ptosis

3. Rarely have diplopia—owing to symmetry of disease

4. No variability (as in myasthenia gravis)

10.What are the features of blepharophimosis syndrome?

Blepharophimosis syndrome (Fig. 37-4) is a congenital autosomal dominant disorder characterized by ptosis, epicanthus, blepharophimosis (narrowing of the palpebral fissure in all dimensions), and telecanthus (widening of the distance between the medial canthi). Some patients also may demonstrate a flat nasal bridge, lower eyelid ectropions, and hypoplastic orbital rims.

11.What are the signs and symptoms of myasthenia gravis?

The history of any patient with acquired ptosis should include questions searching for symptoms of myasthenia gravis. Patients may comment on variability in the degree of ptosis from day to day. They also may notice increased ptosis during periods of fatigue or toward the end of the day. They may give a history of diplopia or difficulty with swallowing as well as dysphonia, dyspnea, and proximal muscle weakness.

Figure 37-4.  Blepharophimosis with bilateral ptosis, eyelid phimosis, telecanthus, and epicanthus inversus. (From Kanski JJ: Clinical Ophthalmology: A Test Yourself Atlas, ed 2, New York, Butterworth-Heinemann, 2002.)

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On examination, patients may demonstrate eyelid fatigue on sustained upgaze, with curtaining of the eyelid on returning to the primary position. They also may demonstrate a Cogan’s eyelid twitch after attempted upgaze. On return to primary position, the eyelid may show an upward twitch before it settles to its final resting place. Orbicularis strength may be weak, allowing the examiner to open the patient’s eyelids even during attempted forceful closure.

KEY POINTS: FEATURES OF OCULAR MYASTHENIA GRAVIS

1.Ptosis—variable over time

2.Ocular misalignment

3.Fatigability of eyelids

4.Cogan’s lid twitch

5.Orbicularis weakness

12.What measurements should be taken during the preoperative examination of patients with ptosis?

•Marginal reflex distance: The distance from the corneal light reflex in primary gaze to the upper eyelid margin; it demonstrates the distance of the upper eyelid from the visual axis; evaluated in primary position with the action of the frontalis muscle negated. The normal MRD is 4.0 to 4.5 mm.

•Levator function: Measures the entire excursion of the eyelid in millimeters from extreme downgaze to upgaze, with the action of the frontalis muscle manually negated; determines the surgical procedure to be performed; function is considered to be normal (>15 mm), good (>8 mm), fair (5 to 7 mm), or poor (>4 mm).

•Eyelid crease height: The crease height is the distance from the eyelid margin to the skin crease. Normally the crease height is 8 to 10 mm and is higher in women.

•Palpebral fissure width: The distance between the upper and the lower lid margins. This is not an accurate measurement of ptosis because the lower eyelid position can affect this value (e.g., Horner’s syndrome with reverse ptosis of the lower eyelid).

Other critical parts of the preoperative evaluation include a careful pupillary examination for aniso-

coria, a cover test for strabismus, and evaluation of corneal sensation and tear film. Often a Schirmer test is performed to measure basal tear production. The lid position is carefully evaluated in primary position with the action of the frontalis muscle negated. The eyelid position is also evaluated in downgaze, looking for eyelid lag that suggests congenital ptosis or previous thyroid ophthalmopathy. The eyelid is evaluated in upgaze for signs of muscle fatigue and curtaining, suggesting myasthenia gravis. History should include a history of contact lens wear, with an evaluation for giant papillary conjunctivitis or a lost contact lens under the upper lid. Finally, it is important to document the presence of a good Bell’s phenomenon (upshoot of the cornea with eyelid closure).2

13.How does Hering’s Law affect ptosis?

Hering’s Law of equivalent innervation of yoke muscles applies to the two levator muscles. It needs to be considered during the preoperative evaluation to determine accurately the degree of ptosis on each side. The normal eyelid in a patient with unilateral ptosis may become ptotic when bilateral stimulation is broken. The eye with which the patient prefers to fixate affects the degree to which Hering’s Law contributes to ptosis. If the ptotic eye is preferred for fixation, the opposite eyelid may develop

a retracted position because of increased stimulation during attempts to open the ptotic eyelid. On occluding the ptotic fixating eye, the previously retracted eyelid may resume a more normal position.3

14.What is the Neo-Synephrine test?

The Neo-Synephrine test is an evaluation of the effect of Müller’s muscle contraction on the degree of ptosis. One drop of 2.5% phenylephrine is placed in the eye. After 5 minutes, the degree of ptosis is reevaluated. The phenylephrine causes contraction of the sympathetic Horner’s muscle, sometimes

causing dramatic improvement in the degree of ptosis. If phenylephrine corrects the ptosis completely, many surgeons elect to perform a Müller’s muscle resection as opposed to a levator resection.4

15.What are the surgical and nonsurgical approaches to the correction of ptosis?

The most common surgical approaches to ptosis correction include levator resection, from either an internal or an external approach; Müller’s muscle resection; and frontalis suspension. A nonsurgical option is ptosis eyelid crutches, which may be secured to spectacle lenses. Although rarely used,

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spectacle adaptations are a reasonable option for patients with neurologic ptosis who have a poor Bell’s phenomenon and are considered to be at high risk for exposure keratopathy.5

16.What are the complications of ptosis surgery?

The most common complication is overcorrection or undercorrection of the ptosis and/or abnormalities in eyelid contour. Other complications include scarring, wound dehiscence, eyelid crease asymmetry, loss of eyelashes, conjunctival prolapse, upper lid ectropion and/or tarsal eversion, eyelid lag on downgaze, and lagophthalmos on eyelid closure, leading to dry eyes or exposure keratopathy, corneal thinning, ulceration, and/or scarring. In addition, the rare but vision-threatening complication of retrobulbar hemorrhage is a risk with all eyelid surgery, and precautions must be taken to discontinue all medications or supplements that may cause prolonged bleeding or clotting times. Last, although rare, infection is a potential complication.6

17.What is Marcus Gunn’s jaw-winking syndrome?

Marcus Gunn’s syndrome is a unilateral congenital ptosis with synkinetic innervation of the levator and ipsilateral pterygoid muscle. It is caused by aberrant connections between the motor division of cranial nerve V and the levator muscle. Patients demonstrate retraction of the ptotic eyelid on stimulation of the ipsilateral pterygoid muscles by either opening the mouth or moving the jaw to the opposite side.

18.Describe the anatomy of the Whitnall’s ligament and its significance in ptosis.

The Whitnall’s ligament, also known as the superior transverse ligament, is a condensation of collagen and elastic fibers on the anterior levator sheath as it changes from muscle to aponeurosis. It attaches medially near the trochlea and laterally traverses through the lacrimal gland, attaching to the lateral orbital wall approximately 10 mm above the lateral orbital tubercle. It serves as a suspensory ligament for the upper eyelid and is the point at which the vector forces of the levator muscle transfer from an anterior–posterior direction to a superior–inferior direction. It is an important landmark for performing large levator resections.2

19.What is the concern when Horner’s syndrome presents with pain?

Patients with neck pain, facial pain, or headache and acute Horner’s syndrome should be suspected of having a carotid artery dissection. Workup should be urgent and include magnetic resonance imaging or angiography of the head and neck. Carotid Doppler sonography is not accurate in detecting carotid artery dissection. A carotid dissection usually requires urgent anticoagulation and neurovascular consultation.7

KEY POINTS: FEATURES OF HORNER’S SYNDROME

1.Mild ptosis (1-2 mm)

2.Miosis

3.Anhidrosis

4. Reverse ptosis of the lower eyelid

5. Hypopigmentation of iris (congenital cases)

20.Name some useful tests for diagnosing myasthenia gravis.

•Ice test (in office)

•Blood tests:

Acetylcholine receptor antibody test: Binding antibodies are detectable in up to 90% of patients

with systemic myasthenia gravis (MG) and up to 70% of patients with ocular MG, with false-negative results in 50% of cases.

MuSK antibodies: These are antibodies to muscle-specific kinase. In those patients with seronegative MG (no antibodies to acetylcholine receptors), testing for MuSK antibodies may be positive in 40 to 70%.

•Edrophonium chloride (Tensilon) test

•Single-fiber electromyography (orbicularis muscle)8

21.Name some causes of acquired ptosis in young adults.

Levator aponeurosis dehiscence can certainly occur in a younger age group, but ptosis in younger adults should prompt thought of other causes as well. History and clinical exam should look for