Fig. 22.1
Eyelid anatomy in cross section. (a) Non-Asian eyelid with the orbital septum (blue) inserting on the levator aponeurosis (green). Müller’s muscle (red) originates from the levator muscle but lies below the levator aponeurosis. (b) Asian variation. The orbital septum (blue) fuses onto the levator (green) below the superior tarsal border or onto the tarsus [4]. Müller’s muscle (red) still lies below the levator aponeurosis in a post-aponeurotic space
The pretarsal and preseptal portions of the orbicularis muscle are innervated by the seventh cranial nerve and are responsible for eyelid closure. The frontalis muscle originates from the galea aponeurotica and inserts into the deep skin of the brow. The frontalis muscle serves as a secondary elevator of the lid, transmitting its force through the skin and orbicularis. The orbital septum is located posterior to the orbicularis muscle. It originates from the superior orbital rim and, in non-Asians, inserts into the levator aponeurosis 3–5 mm above the upper border of the tarsus (Fig. 22.1a). In the Asian eyelid, the insertion is often lower on the tarsus (Fig. 22.1b). The lid crease is thus frequently obscured by a lower overhanging lid fold or even eliminated by the interruption of the anterior attachments of the levator aponeurosis to the overlying pretarsal orbicularis and skin. Jeong et al. compared nine Korean eyelid cadavers to five Caucasian and found three causes for a lower or absent eyelid crease in the Asian eyelid. First, the orbital septum in Asian eyelid fuses to the levator aponeurosis at variable distances below the superior tarsal border. Second, preaponeurotic fat pad protrusion and a thick subcutaneous fat layer in Asian eyelids prevent levator fibers from extending toward the skin near the superior tarsal border, and finally the primary insertion of the levator aponeurosis into the orbicularis muscle and into the upper eyelid skin occurs closer to the eyelid margin in Asians [2]. Immediately posterior to the orbital septum lies the preaponeurotic fat pad. This is an important surgical landmark, because the levator aponeurosis is located just beneath the preaponeurotic fat.
The tarsus provides structural stability for the upper eyelid and consists of a semilunar, malleable, fibrous plate measuring about 1 mm in thickness, 22–25 mm in length, and 9–10 mm in height. The posterior surface of the tarsus is covered with conjunctiva, which is firmly adherent, forming the inner palpebral surface of the eyelid. Above the tarsal plate, the conjunctiva is bound tightly to the underlying Müller’s muscle for the first 8–10 mm and then becomes more loosely attached superiorly.
Müller’s muscle is a smooth muscle, innervated by the sympathetic chain. It originates from the posterior layer of the levator palpebrae superioris, inferior to Whitnall’s ligament, and inserts into the upper border of the tarsal plate. The levator muscle , a striated muscle, is innervated by the third cranial nerve. It originates from the periorbita just above the annulus of Zinn and gradually fans out as it courses forward over the underlying superior rectus muscle. The levator’s anterior muscular sheath becomes quite thickened and ends abruptly as a fascial band called Whitnall’s superior transverse ligament. Whitnall’s ligament appears to provide suspensory support for the levator, redirecting vector forces from horizontal in the orbit to vertical in the lid. It may also act as a check ligament to prevent posterior movement of the levator muscle [3].
Just inferior to Whitnall’s ligament , the levator muscle divides into an anterior portion that becomes the levator aponeurosis and a posterior portion that is continuous with Müller’s muscle. The levator aponeurosis is often stated to continue downward 14–20 mm before reaching its insertion. In our experience with children, however, the length of the tendon is much shorter, usually measuring 10–15 mm. As described earlier, the most superior fibers of the aponeurosis insert into the interfascicular septae of the pretarsal orbicularis muscle. Although a consensus has been reached regarding this portion of the aponeurotic insertion, debate continues over the importance of the termination site of the remaining fibers on the anterior surface of the tarsus. Classical teaching is that the majority of terminal fibers insert directly onto the inferior two-thirds of the anterior surface of the tarsus and that levator muscle contraction pulls on the tarsus in this fashion [5, 6]. In fact, probably only a small percentage of the fibers adhere tightly in this location, with only some of the most distal fibers attaching firmly as a thicker bundle across the lower 3–4 mm of the tarsus [5, 6].
A number of anatomical dissections have documented that most of the aponeurotic terminal fibers insert into the fascial septae of the pretarsal orbicularis [3, 7, 8]. The levator aponeurosis thus appears to exert its major force of retraction to the anterior lamella, rather than directly to the tarsus. This concept is supported by Fig. 22.2, which demonstrates the developing attachment of the aponeurosis to the orbicularis muscle in a 105–mm embryo [7]. The relationship between the insertions of the levator aponeurosis and Müller’s muscle and the role they play in elevating the eyelid when the levator muscle contracts form the basis for continuing debate. These issues are discussed more extensively in the surgical treatment section of this chapter.
Fig. 22.2
Upper lid section of an embryo. A section through the upper lid of a 105–mm embryo demonstrating the attachment of the levator aponeurosis to the orbicularis oculi. MM Müller’s muscle, SO septum orbital, LPS levator palpebrae superioris, TP tarsal plate (From Werb [66]. Reprinted with permission from Taylor & Francis)
Pathophysiologic Classification
An attempt to understand the etiology of the ptosis in every patient is essential for assuring successful management. Although there are alternative methods for classifying pediatric ptosis, it is useful to divide types of ptosis into groups based on pathophysiologic mechanisms. Such categorization assists the surgeon in selecting the most appropriate surgical procedure. The four main pathophysiologic categories are myogenic, aponeurotic, neurogenic, and mechanical. Trauma is not considered a separate entity in our classification system, because most traumatic causes of ptosis fall into one of the four main categories. In addition to being able to distinguish between the various mechanisms, one must also be able to differentiate true ptosis from pseudoptosis, where the droop is due to other factors external to the lid, such as enophthalmos or microphthalmos.
Myogenic Ptosis
This type of ptosis is caused by an abnormality in the embryonic development of the levator palpebrae muscle. As a result, the levator muscle is usually dystrophic, with fibrotic or fatty tissue replacing healthy muscle fibers. The fibrotic nature of the muscle abnormality is exemplified by the resultant decrease in eyelid excursions. The eyelid not only demonstrates poor elevation in upgaze but also lags behind the motion of the globe on downgaze. Whereas healthy muscle is able to relax, allowing the eyelid to be lowered, the fibrotic tissue remains taut. As a result, many patients also demonstrate some degree of lagophthalmos , which also is frequently present when the patient is asleep. In some cases the orbital septum also appears to restrict motion of the lid, and when incised during surgery, an increased excursion of the lid can be demonstrated manually or voluntarily if the patient is not under general anesthesia.
The myogenic mechanism is responsible for the majority of congenital ptosis cases. The term “simple congenital ptosis ” is sometimes used to refer to this particular type of congenital ptosis (Fig. 22.3). Myogenic ptosis is usually stationary and can occur unilaterally or bilaterally. An associated superior rectus weakness is reported in 5% of cases and may also be observed as a double-elevator palsy [9]. Usually no family history is present, but this type of ptosis can be transmitted as an autosomal-dominant trait. Light and electron microscopic studies have confirmed the dystrophic appearance of the levator muscle in congenital cases [8, 10].
Fig. 22.3
Simple congenital ptosis . (a) Unilateral; (b) bilateral
Myogenic ptosis can be classified as mild (≤2 mm), moderate (3 mm), or severe (≥4 mm); most importantly, the degree of ptosis correlates inversely with the amount of levator function present – the greater the ptosis, the poorer the action of the levator. One of the more severe forms of myogenic ptosis is associated with blepharophimosis and for convenience is often categorized as the congenital eyelid syndrome or, more specifically, the blepharophimosis syndrome (BPES) (Fig. 22.4). This syndrome consists of blepharophimosis, epicanthus inversus, telecanthus, and ptosis. Lateral lower lid ectropion is sometimes also seen with this condition. The blepharophimosis eyelid syndrome is often found to be associated with mutations on the FOXL2 gene, and thus genetic testing is always recommended to patients and their parents with suspected BPES. Type I BPES is associated with premature ovarian failure. All female patients with FOXL2 gene mutation should have a consultation with an endocrinologist and an ultrasound of the ovaries upon reaching puberty.
Fig. 22.4
Congenital eyelid or blepharophimosis syndrome (BPES) : blepharophimosis, epicanthus inversus, telecanthus and ptosis
Another myogenic condition is the congenital orbital fibrosis syndrome involving the extraocular muscles in addition to the levator muscle (Fig. 22.5). This is an extremely rare disorder that may be sporadic or familial. Although bilateral cases are more common in the literature, our experience has been greatest with unilateral cases with the involved eye rotated down and in [11]. The severe degree of ptosis is accompanied by enophthalmos. The child may attempt to compensate for the associated ptosis and restricted globe with adoption of a strange head position and use of the brows. If there is a strong family history, it is referred to as CFEOM1 . CFEOM2 is an autosomal recessive disorder caused by mutation in the ARIX gene (602753) on chromosome 11q13 and is characterized by bilateral ptosis with eyes fixed in an exotropic position. CFEOM3 can be unilateral. CFEOM4 , also known as Tukel syndrome, maps to 21q.CFEOM5 and is caused by mutation in the COL25A1 gene (610004) on chromosome 4q25 [12].
Fig. 22.5
Congenital orbital fibrosis syndrome
Although we use the term “myogenic” predominantly to describe a type of ptosis characterized by dysembryogenesis of the levator muscle, there are other dystrophic types of ptosis that present later in life. These include muscular dystrophy and chronic progressive external ophthalmoplegia and are relatively uncommon forms of pediatric ptosis. Chronic progressive external ophthalmoplegia (CPEO) is a mitochondrial disease. It results in a bilateral, severe, progressive ptosis with poor levator function. In addition, it can be associated with heart block, retinal pigment degeneration, and foveal atrophy (Kearns Sayre syndrome ). Figure 22.6 depicts a patient with Kearns-Sayre who suffers from ptosis and poor vision. Figure 22.7 is another patient with CPEO. Mitochondrial diseases result from failures of the mitochondria, specialized compartments present in every cell of the body except red blood cells. Mitochondria are responsible for creating more than 90% of the energy needed by the body to sustain life and support growth. When they fail, less and less energy is generated within the cell. Cell injury and even cell death follow. If this process is repeated throughout the body, whole systems begin to fail, and the life of the person in whom this is happening is severely compromised. Diseases of the mitochondria appear to cause the most damage to cells of the brain, heart, liver, skeletal muscles, kidney, and the endocrine and respiratory systems.
Fig. 22.6
Patient with CPEO and heart block (Kearns Sayre). (a) Preoperative photo showing bilateral ptosis. (b) Postoperative photo 6 years after bilateral autogenous fascia lata slings. (c) Fundus photograph of the right eye showing pigmentary retinopathy. (d) OCT, right and (e) OCT, left eye showing serious outer retinal atrophy with preservation of retinal pigment epithelium and photoreceptor cells in the macula only and virtually complete atrophy of these outer retinal layers beyond the very central macula
Fig. 22.7
Patient with severe ptosis due to CPEO. (a) Photo at age 9 years showing normal eyelid levels with no ptosis or motility limitation. (b) Photo of the same patient 2 years later at age 11 after rapid onset of this mitochondrial disorder with severe ptosis and head tilt. (c) 6 months post-op bilateral silicone frontalis slings, purposely under-corrected with brows relaxed, but no head. (d) Same day at 4 months post-op with use of frontalis muscles for brow elevation
Myotonic dystrophy is a multisystem disease associated with weakness of peripheral muscles. It is a trinucleotide repeat, autosomal-dominant disease characterized by an inability to relax (myotonia) and muscle wasting (muscular dystrophy). Myotonic dystrophy type 1 is caused by mutations in the DMPK gene (chromosome 19), while type 2 results from mutations in the CNBP gene (chromosome 3). The specific functions of these genes are unclear. Oculopharyngeal muscular dystrophy is an inheritable form of ptosis that usually does not appear until the fifth decade of life. It presents with a progressive ptosis, weakness of the extraocular muscles, dysphagia, and proximal limb weakness. It can be autosomal dominant or recessive. Genetic testing for GCG trinucleotide expansions in the PABPN1 gene is recommended if this dystrophy is suspected.
Finally, thyroid eye disease , while usually associated with proptosis, eyelid retraction, and, less commonly in children, strabismus, can rarely present as a myogenic ptosis due to inflammatory infiltration of the eyelid retractors. Figure 22.8 depicts a 17-year-old patient with thyroid eye disease and acquired myogenic ptosis.
Fig. 22.8
A 17-year-old patient with left upper lid ptosis due to thyroid eye disease
Aponeurotic Ptosis
Aponeurotic ptosis , in contrast to the myogenic form, is thought to be caused by a defect in the tendon that may lead to ineffective transmission of the force generated by the contracting levator muscle. Since the levator muscle itself is healthy, this type of ptosis is characterized by normal levator function. The amount of ptosis can be variable, but a dehiscence or disinsertion of the aponeurosis is usually accompanied by a higher than normal lid crease (Fig. 22.9). Although this type of mechanism is most commonly associated with involutional ptosis in elderly patients, it can also be observed in children who either have a developmental defect or have suffered trauma such as forceps injury during birth.
Fig. 22.9
Aponeurotic ptosis . Ptosis of the left upper lid with higher lid crease on the affected side
Neurogenic Ptosis
Defects in innervation occurring during embryonic development can lead to neurogenic types of ptosis. Abnormal or synkinetic connections can occur between the third and fifth cranial nerves, producing a Marcus Gunn jaw-winking type of ptosis. An isolated defect of the third cranial nerve can lead to a congenital third-nerve palsy or paresis. Abnormalities involving parasympathetic innervation produce a congenital Horner syndrome. The latter two entities can also be acquired during childhood, usually secondary to trauma or tumor.
Marcus Gunn jaw-winking ptosis is fairly common, accounting for approximately 2–13% of congenital ptosis cases [13–15]. This type of ptosis is characterized by elevations of the lid coinciding with sucking or chewing movements (Fig. 22.10). The lid usually elevates when the internal and external pterygoid muscles move the jaw from side to side. Maximum elevation seems to occur most frequently when the jaw opens and the mandible moves to the side opposite the ptosis. Marcus Gunn ptosis occurs almost always unilaterally, more frequently on the left, and is usually sporadic without an inherited pattern. Some authors have reported that the condition improves with age [15, 16], but, more than likely, improvement results from learned behavior and better control of the lid’s fluctuating position. Surgical intervention may also be a reason that this synkinetic phenomenon is seen infrequently in the adult population. We have personal experience with one patient who has had persistent jaw winking into her middle-aged years.
Fig. 22.10.
Marcus Gunn jaw-winking ptosis . (a) Ptosis of the right upper lid; (b) elevation of the right upper lid when the mandible moves to the opposite side
Congenital third-nerve palsies are rare. A complete third-nerve palsy is characterized by complete ptosis, a dilated nonreactive pupil, absent elevation, depression, and adduction of the eye on the involved side (Fig. 22.11). The palsy can also be partial, with varying degrees of dysfunction of the lid, pupil, and rectus muscles. Congenital third-nerve palsies are rarely associated with aberrant regeneration. In such instances, the ptotic lid may be seen to elevate on attempted elevation, depression, or adduction of the globe (Fig. 22.12). In contrast, acquired third-nerve palsies are more frequently associated with aberrant regeneration.
Fig. 22.11
Congenital third-nerve palsy . Complete ptosis associated with depression and abduction of the globe
Fig. 22.12
Bilateral congenital third-nerve palsies with aberrant regeneration. (a) Left gaze: right upper lid is retracted and left upper lid is ptotic. (b) Right gaze: right and left upper lids assume a normal position
Congenital Horner syndrome is caused by a disruption in parasympathetic innervation producing the classic triad of ptosis, miosis, and anhydrosis. One to 3 mm of ptosis of the upper lid is present, along with 1–2 mm of inverse ptosis of the lower lid. In addition to a small pupil that fails to dilate, a decrease in pigmentation of the iris on the involved side can also occur (Fig. 22.13). Heterochromia is more characteristic of the congenital form of Horner syndrome and thus can be useful in differentiating congenital cases from those that are acquired. The differentiation between cases is very important, in that any Horner syndrome acquired in childhood must be carefully evaluated for a potential tumor affecting the sympathetic pathway (Fig. 22.14). Rarely, neurogenic ptosis can be associated with an ophthalmoplegic migraine.
Fig. 22.13
Congenital Horner syndrome . (a) Ptosis and miosis in an infant with congenital idiopathic left Horner syndrome. (b) After instillation of 10% cocaine into both eyes at 0 and 5 min. When checked 45 min later, the right pupil was dilated, but the left pupil was not (Courtesy of David Kozart)
Fig. 22.14
Acquired Horner Syndrome due to a right-sided neck venolymphatic malformation. (a) Right-sided ptosis and miosis. (b) 2.5% phenylephrine testing: 5 min after one drop in the right eye shows improvement of the ptosis
Although not truly a neurogenic cause, myasthenia gravis can also lead to ptosis in the pediatric age group. Myasthenia gravis may manifest by an increasing degree of ptosis as the day progresses; however, simple congenital ptosis associated with fatigue of the frontalis muscle due to prolonged use can also present in this fashion. Associated disturbances of extraocular muscle function are common in myasthenia and are helpful in differentiating these two conditions. Weakness of the orbicularis muscle on forced closure is also a useful sign in children. The Cogan lid twitch is one in-office examination test that can help in the diagnosis of myasthenia gravis. The Cogan lid twitch is elicited by having the patient look in downgaze, followed with upgaze. As the affected eye saccades up, the upper lid overshoots. Another in-office test readily available to the clinician is the ice test. An ice pack is applied to the affected upper eyelid for 5 min. A positive test is the improvement of ptosis by greater than 2 mm or more. This temporary improvement in ptosis is due to the cold decreasing the acetylcholinesterase breakdown of acetylcholine at the neuromuscular junction. More acetylcholine collects in the junction and therefore increases the muscle contraction.
The serum anti-ACh receptor antibody titer is an assay that measures three different anti-ACh receptor antibodies found in myasthenia. These are the binding antibodies, blocking antibodies, and modulating antibodies. Binding antibodies are present in 85–90% of systemic MG patients and 50% of ocular MG patients. When binding antibodies are negative, blocking and modulating antibodies are then tested.
The challenge to this test, however, is that 10–15% of patients with systemic MG will test negative, as will 30–50% of patients with ocular MG. If the suspicion for MG remains high despite normal Ach receptor testing, MuSk assays can be tested [17].
Finally, if laboratory testing remains negative, the Tensilon test plays a very important role in diagnosing myasthenia in pediatric patients. The Tensilon test is most reliably performed by a neuro-ophthalmologist, but this may not always be practical. For patients weighing less than 30 kg, an intravenous dose of 0.15 mg/kg of edrophonium chloride is recommended. Twenty percent of the dose is initially injected, and the eyelid position is reevaluated at 1 min. If the eyelid position is unchanged, then an additional 40% of the dose is injected. This can be repeated once more if no effect is observed. Atropine (0.4 mg) for intravenous injection should be readily available to treat any significant cholinergic side effects. As an alternative test to intravenous administration of edrophonium, neostigmine methylsulfate can be given intramuscularly (the Prostigmin test). The recommended dose is 0.04 mg/kg, not exceeding a total dose of 1.5 mg (the adult dose). The neostigmine is injected along with atropine, and after 30–45 min, the eyelid position is reassessed. The obvious advantage of this method of testing is that by the time the Prostigmin has taken effect, the child is more likely to have stopped crying and is more easily observed. Regardless of the method of testing, however, if the ptosis is temporarily reversed, a diagnosis of myasthenia is confirmed, and treatment under the direction of a neurologist is then essential. Antibody tests and single-fiber electromyography can also be helpful in ruling out a diagnosis of myasthenia gravis.
Mechanical Ptosis
Mechanical ptosis is most commonly caused by the inability of the levator muscle to function properly due to the weight of a tumor mass, foreign body, or soft tissue swelling (Fig. 22.15). Although the levator muscle and aponeurosis are usually normal, these structures may become infiltrated by the disease process. Infantile hemangiomas and plexiform neurofibromas, which are commonly responsible for mechanical ptosis in children, are notorious for infiltrating the levator muscle complex and making simple excision difficult. Cicatricial processes secondary to trauma can also mechanically restrict the eyelid in a ptotic position even with an otherwise normally functioning levator.
Fig. 22.15
Left upper lid infantile hemangioma causing mechanical ptosis
Traumatic Ptosis
Traumatic ptosis can be considered congenital if the injury is presumed to have occurred in utero, secondary to amniocentesis, for example, or from injury during the birthing process. Congenital ptosis that is presumed to be traumatic in origin must be differentiated from the true myogenic form.
While traumatic ptosis can be due to any of the four pathophysiologic mechanisms described above, it may be difficult to identify the exact cause immediately following injury (Fig. 22.16). In some instances, such as a forceps or scissors injury occurring during birth, the cause may be immediately evident and early repair of the laceration is appropriate. For most cases of traumatic ptosis, however, the etiology is less clear. For this reason, it is important that such patients be observed for at least 6–12 months prior to surgical repair, unless the threat of amblyopia mandates earlier intervention. With time, the amount of ptosis may improve sufficiently, or at least the etiology may become more apparent so that the appropriate surgical procedure can be selected.
Fig. 22.16
Traumatic ptosis . Acute onset of ptosis in a 3-year-old whose head was run over by the wheel of a car
In cases of penetrating trauma, a clue may be present as to the exact cause of the ptosis. If orbital fat is exposed in the wound, the underlying levator muscle is very likely to have been lacerated. Figure 22.17 depicts such a case. The presence of orbital fat warrants immediate exploration of the wound and repair of the lacerated levator muscle if necessary. While accidental trauma is most common, iatrogenic cases of ptosis can occur secondary to orbital, vascular, strabismic, or craniofacial surgical procedures. In general, if the threat of amblyopia can be successfully managed with occlusion therapy, surgical intervention should be delayed for the recommended 6–12 months, because many of these cases will spontaneously improve.
Fig. 22.17
Left traumatic ptosis due to an upper eyelid laceration with fat prolapse
Many cases of apparent ptosis are not due to an actual abnormality in the eyelid but rather to other orbital, adnexal, or ocular problems. Identifying the true etiology is critical to assure proper correction of the problem. Pseudoptosis must be differentiated from true ptosis and can occur secondary to a number of conditions, including microphthalmos, anophthalmos, enophthalmos, phthisis bulbi, hypertropia, as well as eyelid inflammations, or infections (Figs. 22.18 and 22.19).
Fig. 22.18
Right microphthalmos causing a pseudoptosis of the right upper lid
Fig. 22.19
(a) Acute onset left ptosis. (b) Membranous conjunctivitis is cause of droop. (c) Resolution of left ptosis is seen 3 weeks after topical steroid drops
Common Causes of Pseudoptosis
- 1.
Contralateral eyelid retraction
- 2.
Facial asymmetry (e.g., plagiocephaly)
- 3.
Contralateral proptosis
- 4.
Enophthalmos
- 5.
Eyelid inflammation (e.g., conjunctivitis with or without membranes or pseudomembranes)
- 6.
Microphthalmos, anophthalmos, or nanophthalmos
- 7.
Phthisis bulbi
- 8.
Anisometropia (with smaller eye being more hyperopic or less myopic)
- 9.
Vertical strabismus
Clinical Evaluation
One of the more challenging aspects of managing congenital ptosis is obtaining adequate data upon which to base the surgical plan. Unlike most patients, children cannot be expected to fully cooperate, and thus accurate measurements cannot always be obtained. For this reason, taking a thorough history and observing the patient, often at a distance during play, are essential components of the evaluation. Obviously, if any measurements are obtainable, they are a welcome addition to the clinical assessment.
History
The ptosis evaluation should begin with a thorough history . Was the ptosis present at birth or acquired shortly thereafter? Has it improved, been stable, or worsened over time? Acquiring the details of the child’s delivery is important in assessing the possibility of traumatic injury during the birthing process. Any illness or hospitalization should also be noted to rule out diseases, disorders, or syndromes that can be related to the presence of ptosis. A review of developmental milestones should also be obtained. Prior surgical interventions must be documented, particularly craniofacial procedures or other ophthalmic procedures. A family history may uncover an inherited type of ptosis.
A careful history can be extremely useful in revealing the clinical characteristics of a child’s ptosis. The parents can frequently describe the degree of the ptosis and whether it appears to interfere with the child’s vision. In today’s age of smartphones, it is best to ask if the parents have any pictures to document severity and age of onset. They may notice the effort to elevate the lid with arching of the brows or the adoption of a chin-up head position. The variability of the ptosis should also be addressed. Is the ptosis constant, or does the lid level change over the course of the day? Is there evidence to support a synkinetic mechanism? Parents may note fluctuations in lid position while feeding their child. Although very rare, myasthenia gravis can cause congenital ptosis, and, as mentioned earlier, a variability in the degree of ptosis that markedly worsens toward the end of the day should alert the physician to this possibility. On the other hand, many parents will report an increase in the degree of the droop as the day progresses in cases of myogenic ptosis. This is particularly common in cases of severe myogenic ptosis and is related to fatigue of the brow from an attempt to elevate the lid. This same mechanism is also responsible for the increased droopiness present during illness and sleepiness.
Observation
As discussed earlier, observation becomes one of the strongest tools for examining young patients. As one obtains the history from the parents, one can also gather important clinical information by simply watching the child from a nonthreatening distance. If the child is distracted or disinterested, playful interactions can also be effective in capturing his/her attention. Such characteristics such as the degree of the ptosis, the use of the frontalis muscle, the adoption of a chin-up head position, the variability of the lid position, and the presence of strabismus can all be assessed without touching or frightening the patient.
Physical Examination
All examinations of pediatric patients with ptosis must include a careful assessment of visual function. Certainly one of the most potentially devastating sequela of a ptotic lid is amblyopia. Although more formal measurements of visual potential using pattern recognition cards, HOTV, Allen cards, and Snellen letters are ideal, they are not always obtainable in children (see Chap. 10). The clinician must frequently rely on clinical observations such as whether a fixation preference is present. The 10-prism diopter test can be very helpful in detecting moderate to severe amblyopia in the eye on the side of the ptosis. The best visual assessment for preverbal and nonverbal patients is Teller visual acuity measurement, which can be obtained as early as 3 months of age. This form of preferential gaze testing is very effective in identifying the presence of amblyopia and is covered in detail in Chap. 10.
Examination of the size and reactivity of the pupils is important from the standpoint that pupillary involvement can indicate an innervational etiology for the ptosis (i.e., third-nerve palsy or Horner syndrome). Similarly, a motility examination must be performed to identify any accompanying superior rectus weakness or any other type of strabismus. A normal Bell’s phenomenon should be documented, if possible. The ability to elevate the globe, at least to some degree, is crucial both for protection of the globe and for proper tear film exchange over the cornea. The degree of lagophthalmos and exposure as well as the quality of tear film exchange following ptosis surgery are central concerns and are significantly influenced by the ability of the globe to elevate upon forced closure of the eyelids. A poor Bell’s phenomenon can alert the clinician to more strongly consider the use of a temporary suture tarsorrhaphy or lower lid traction suture for corneal protection during the first few days following ptosis repair.
Often newborns, when seen in the office, are sleeping. Even after arousal, infants may remain somnolent. A great examination tool is to elicit the eye-popping reflex. This is where a newborn will open his or her eyes when the room lights are dimmed or turned off [18]. Figure 22.20 depicts a newborn with ptosis before and after turning off the room lights.
Fig. 22.20
Eye-popping reflex . (a) A newborn with right ptosis that is not appreciable. (b) Photo taken immediately after turning out the room lights exhibits the infant’s eye-popping reflex and uncovers the right congenital ptosis
As for the external examination , one should attempt as many routine preoperative ptosis measurements as reasonably possible. In young children, only estimates performed at a distance may be obtainable, but even these can be of real practical value. The margin reflex distance (MRD1) is most useful in that it measures the distance of the upper lid margin from an apical light reflex at the center of the cornea. This measurement is the most accurate method for assessing the degree of ptosis in that it is solely indicative of upper lid position and is not influenced by the position of the lower lid. In contrast, measurement of the vertical fissure height (VFH) , the distance from the upper lid margin to the lower lid margin, is always affected by the lower lid position. The MRD1 can easily be estimated by recognizing that the vertical dimension of the cornea is approximately 10 mm, and the apex of the cornea, therefore, centers a scale of 0 to +5 mm at the superior limbus and 0 to −5 mm at the inferior limbus. The normal MRD1 in children is approximately +4.0 mm, but some people have an MRD closer to 3 at rest. If the ptosis splits the visual axis, the MRD1 is 0, and if the lid goes below the center, then negative numbers apply (Fig. 22.21). MRD2 refers to the position of the lower lid margin in relation to the apical light reflex. In practical terms for ptosis, the MRD1 is really the most valuable measurement (Table 22.1).
Fig. 22.21
Schematic comparing ptosis (in mm) to MRD1
Table 22.1
Classification of ptosis based on millimeters of eyelid droop compared to MRD1
Amount of ptosis | Millimeters of droop (from normal level) | MRD1 |
|---|---|---|
Mild | ≤2 mm | 3 |
Moderate | 3 mm | 2 |
Severe | ≥4 mm | ≤1 |
When measuring either the MRD1 or VFH, the effect of brow arching should be documented. Additionally, in some cases of what seems to be unilateral ptosis, the opposite eyelid may appear to be in a normal position while it is actually ptotic. This opposite eyelid appears “normal” as a result of the action of the frontalis muscle, which is elevating both upper lids. If the frontalis muscle is relaxed, then the ptosis of the “normal” side will be unmasked. This variation of Hering’s law also has application in regard to levator function. A child may appear to have unilateral ptosis, when, in fact, overstimulation of the affected levator muscle is accompanied by overstimulation of the levator on the opposite side. If not recognized, this can also mask a true ptosis on the less affected side. Failure to identify the bilateral nature of such problems prior to surgery may lead to a less than desirable cosmetic result or even concerns from the patient’s family that a “new” ptosis was caused by the surgery.
In addition to the MRD1 and VFH, the position of the lid crease should be assessed. The distance of the crease from the central aspect of the lid margin is measured in millimeters as the lid is positioned in downgaze. This measurement is most important in cases of unilateral ptosis, since the surgically created lid crease should match the crease on the opposite side.
Although all of the previously described measurements are important, the most essential measurement is the amount of levator function present (Fig. 22.22). This measurement will most significantly influence the decision as to which surgical procedure is most appropriate. If possible, the frontalis muscle should first be immobilized by fixing the brow with a thumb. The position of the lid margin in extreme downgaze is then noted on a ruler held next to the eyelid, and the patient is then asked to look up to the ceiling. The distance that the lid margin travels in millimeters is termed the levator excursion and is indicative of the degree of levator function present. When examining young infants, one may obtain the same information by fixing the brow and moving a toy in an arc that leads the infant’s eyes from downgaze to upgaze. The amount of levator function can be classified as poor if it is 4 mm or less, fair if 5–7 mm, good if 8–12 mm, and excellent if 13 mm or more [19] (Table 22.2).
Fig. 22.22
Assessment of levator function . Levator function is assessed by measuring the levator excursion, which is the distance in millimeters that the eyelid margin moves from (a) downgaze to (b) upgaze
Table 22.2
Classification of levator function
Levator function | Eyelid excursion |
|---|---|
Excellent | ≥13 mm or greater |
Good | 8–12 |
Fair | 5–7 mm |
Poor | ≤4 mm or less |
In addition to obtaining the above measurements, the ptotic eyelid should be assessed for its response to phenylephrine and for the presence or absence of synkinetic movements, lid lag, or lagophthalmos. Five minutes following the instillation of a single drop of 2.5% phenylephrine to the eye on the ptotic side, the MRD1 should be remeasured. Phenylephrine 10% should be avoided in all patients due to the risk (though remote) of systemic complications [20]. The degree to which the lid position responds to the phenylephrine is an essential factor in the determination of the proper surgical procedure. If the eyelid responds well, then an internal approach procedure involving shortening of Müller’s muscle may be considered for the ptosis repair. Phenylephrine can also increase the VFH, not only by lifting the upper lid but also by contraction of the smooth muscle in the lower lid, causing a change in the MRD2. This further emphasizes the importance of MRD1 over VFH in planning for repair.
The response of the opposite eyelid to unilateral instillation of phenylephrine to the more affected side is also important (Fig. 22.23). As discussed earlier, Hering’s law may be responsible for masking a ptosis of the opposite eyelid. If the ptotic eyelid responds to phenylephrine and elevates out of the visual axis, the need for levator muscle contraction will then become less, and, as a result of Hering’s law , the reduction of levator stimulation will occur on both sides. In such instances, the opposite eyelid, if ptotic to any degree, may have appeared normal before phenylephrine elevated the eyelid on the more severely affected side. This “normal” side will now drop to a lower and sometimes truly ptotic position. This information is important not only to alert parents to the possibility of such a phenomenon occurring postoperatively but also to raise the possibility of the need for bilateral surgery. By using the phenylephrine test to demonstrate the bilateral nature of their child’s problem, parents can thus be better informed and more prepared to participate in any decision regarding unilateral versus bilateral repair.
Fig. 22.23
Phenylephrine test . (a) Prior to instillation of phenylephrine, the right upper lid is ptotic while the left is in a normal position. (b) Following the instillation of phenylephrine, the right upper lid level becomes higher. In this example the left lid also becomes lower as there is less need for the levator muscle to contract of both sides (Hering’s law), thus unmasking a latent ptosis
The synkinetic movements associated with the Marcus Gunn type of ptosis can usually be elicited by giving the infant a bottle, food, or a pacifier. As the infant sucks or chews, variations in the eyelid position are assessed. If synkinetic movements are present, the surgical plan must specifically consider this issue.
The presence of lid lag or lagophthalmos is most helpful in clarifying the etiology of the ptosis. If the ptotic eyelid becomes the higher lid upon excursion from upgaze to downgaze, then lid lag is present. The presence of this finding is particularly characteristic of the myogenic type of congenital ptosis and is due to the fibrotic nature of the levator muscle. Similarly, in the absence of a history of trauma, the presence of lagophthalmos upon gentle eyelid closure also implies a myogenic mechanism. In such instances the cornea will usually be exposed while the child sleeps even prior to surgical intervention. In some cases of congenital ptosis, in addition to the fibrotic nature of the muscle, a vertical shortening of eyelid skin may also contribute to lagophthalmos. Many of these patients also have abnormalities of the orbital septum that become apparent only at the time of surgery.
Since all of these measurements and assessments are potentially difficult in children, we document the position of the eyelids with digital photography. Even when lack of cooperation limits the thoroughness of the external examination, usually at least a few photographs can still be taken. These photographs are frequently useful in supplementing the recorded clinical information, which may have been difficult to obtain during the office examination. In this fashion an appropriate surgical procedure can more confidently be selected. Even when accurate measurements are obtainable, a photograph is always helpful in providing additional information and serving as an available reminder during the operative procedure. In addition, for the proof of medical necessity, clinical photographic documentation of clinically significant ptosis is required by many insurance companies.
Once the external examination is completed, an upright slit-lamp evaluation should be performed on those patients old enough to cooperate. If necessary a hand-held slit-lamp can be used. The quality of the tear film should be assessed, and the cornea should be examined for signs of exposure. Frequently, however, a standard slit-lamp evaluation is impractical, thus forcing one to modify the examination technique. Similar to the technique adopted for a dye disappearance test, fluorescein is instilled in both eyes, and the cobalt blue filter light of the slit lamp is used from a nonthreatening distance of 3–4 ft. to allow at least some assessment of both the tear film and corneal surface. In older children, both a measurement of the tear breakup time (TBUT) and a baseline tear secretion test (BTST) with topical anesthetic can be performed to evaluate basic tear function. Normal corneal sensitivity should also be documented if possible. Normal TBUT is >10 s, and a normal BTST should be >10 mm of wetting the filter paper strip.
Cycloplegic retinoscopy is mandatory for all pediatric patients with ptosis. A significant incidence of with-the-rule astigmatism occurs secondary to the weight of the ptotic lid against the globe [21]. If a sizable refractive error is uncovered, spectacle correction may be required [22]. Most importantly, a significant refractive error should alert the clinician to the possibility of amblyopia, which demands carefully monitoring. The current practice patterns for the treatment of refractive errors in children can be found on the American Academy of Ophthalmology website [23]. Occlusion therapy should be initiated for any patient demonstrating signs of amblyopia. In addition, for infants and very young children with unilateral ptosis, we often recommend patching the normal eye for 0.5–1 h a day as an “insurance policy” against the development of amblyopia, even for those patients who appear to have equal vision in both eyes. A dilated funduscopic examination should also always be performed to complete the evaluation.
Surgical Treatment of Congenital Ptosis
Although most experienced clinicians would agree that surgery is indicated for a 4-month-old infant with severe ptosis and visual deprivation, controversy still exists as to when elective surgery should be performed in young patients without amblyopia. Traditionally, most textbooks have recommended that surgery be delayed until around the age of 5 years, just prior to the child’s entering school. It has been argued that better measurements can be obtained when the child is older and that eyelid anatomy is better defined, thereby allowing the surgeon to achieve more satisfactory results [24–26].
Our approach has been different, however, and, while possibly appearing more radical, has consistently yielded satisfying surgical results from an appearance standpoint as well as good visual outcomes. In general, we recommend that most elective ptosis repairs be performed at approximately 1 year of age unless there is a major threat of visual deprivation (i.e., severe ptosis) requiring earlier intervention. We prefer to defer surgery until the infant is at least 3–6 months old to avoid any added risk of general anesthesia (see Chap. 5). We feel that more than adequate clinical information can be obtained even in the youngest of patients, and we have not found any limitations associated with operating on smaller anatomic structures. We also believe that by operating when patients are very young, we can reduce the emotional trauma often experienced by older children when they must come to the hospital for surgery. This approach is also beneficial for parents, since younger children are easier to manage postoperatively, particularly when applying lubricating drops or ointments for corneal exposure. Most importantly, however, we have found that young children are able to proceed more normally with visual, motor, and social development once their ptosis has been corrected.
Ptosis can interfere with motor development by forcing infants with severe eyelid droop to adopt a chin-up head position to clear the visual axis on the affected side. Although this head position is probably protective in regard to amblyopia, it has the potential to detrimentally affect the learning process of walking as well as putting stress on the cervical spine. In addition, a child’s psychosocial development as he or she interacts with family and friends is significantly influenced by his/her appearance. Children are now exposed at early ages to group interactions at both nursery schools and day care centers, and young children are often very observant and vocal about anything abnormal in another child’s facial appearance. A ptotic eyelid may draw comments that have a negative impact on the social interactions for both the child and his or her family. It is not uncommon for parents to inform us regarding negative comments such as their child being call a “pirate” at school by other children. This can lead to a child feeling alienated or actually being ostracized. By promoting early surgical intervention, we are able to relieve the parents and other family members of unwarranted social pressures and also influence a child’s developing sense of self in a positive fashion. While writing this chapter and reviewing the literature for our first edition of this book in 2001, we discovered that Matthews in 1969 had recommended a similar approach for early ptosis repair based on a large pediatric ptosis series [27].
Even given the advantages stated above, we certainly would not promote earlier intervention if the results were not at least as satisfactory as those achieved with surgery delayed to prekindergarten age. Fortunately, excellent outcomes have been well documented in our experience. We are always careful, however, to discuss all the risks and benefits regarding timing and the choice of surgical procedure with the parents (or responsible guardian) and to inform them that ptosis repair is an elective procedure, unless there is a documented risk of significant amblyopia that requires early repair.
Choice of Operation
Once the decision to operate has been made, the surgeon must then select the procedure that will achieve the best result with the least risk of complications. Surgical procedures can be divided into two mechanistic categories: (1) use of anatomic structures within the eyelid that participate in the lifting force of the levator muscle and (2) use of structures outside of the eyelid that can assist in lid elevation. The first category can be further divided topographically into internal (posterior) and external (anterior) approaches. While the internal approach can be used for levator surgery, our preference is to use this for procedures involving some form of Müllerectomy . We prefer the external approach for aponeurotic advancement and/or levator resection. The second category is really limited to frontalis suspensions. Frontalis suspensions (or slings) can be performed with synthetic materials or with autogenous or preserved fascia lata. The advantages and disadvantages of these materials will be discussed later in this chapter. Although superior rectus surgery has been advocated in the past, such procedures are no longer recommended due to severe corneal exposure problems related to the inability of the upper lid to move over the corneal surface with ocular movements.
A systematic approach to the selection of surgical procedures for pediatric ptosis repair is essential for assuring the best possible results. We have developed specific guidelines based on over 50 years of clinical experience to assist in the selection process, but it is important to recognize that every case of pediatric ptosis is unique in character.
Although, traditionally, most surgeons have relied predominantly on levator function to guide their selection of surgical procedures, we have incorporated the results of the phenylephrine test into our decision-making. If the response to 2.5% phenylephrine achieves the desired postoperative MRD1, then regardless of the degree of ptosis or the amount of levator function, an internal approach consisting of a Müllerectomy with or without tarsectomy is strongly considered. If the response is inadequate, then either an external approach procedure or a frontalis suspension must be selected, based on the amount of levator function present (Table 22.3). In cases of high-risk ptosis, such as third-nerve palsies, CPEO, double elevator palsy, or CFEOM, a minimal (or functional only) improvement in ptosis may be desirable due to the risk of corneal exposure. This may be performed by the undercorrection with a sling or some form of Müllerectomy.
Table 22.3
Selection of ptosis repair based on response to phenylephrine
Response to phenylephrine | Surgical procedure |
|---|---|
Good (MRD1 = 4–5) | Putterman Müllerectomy or modified Fasanella-Servat |
Moderate (MRD1 = 3) | Graded modified Fasanella-Servat or Werb procedure (i.e., graded Müllerectomy with tarsectomy) |
Poor (MRD1 ≤ 2) | Levator surgery or frontalis suspension |
Myogenic Ptosis
The process of selecting the most appropriate surgical procedure for cases of myogenic ptosis begins with the assessment of the patient’s response to topical phenylephrine. We routinely use 2.5% phenylephrine for most patients. Although a higher concentration of phenylephrine 10% does actually stimulate Müller’s muscle to a greater degree, the difference in response to the two drops does not appear to be enough to affect the surgical decision, and the 2.5% concentration greatly reduces the risk of systemic involvement [28]. In general, the height of the lid 5 min following the instillation of 2.5% phenylephrine can be duplicated with resection of the sympathetic muscle of Müller through an internal approach. Contrary to popular belief, Müllerectomies need not be limited to only those patients with 2 mm of ptosis or less [29, 30]. The response to phenylephrine is, in fact, often unrelated to the amount of levator function present. In some cases where only a fair amount of levator function is present (5–7 mm), the ptotic lid’s response to phenylephrine may still be excellent, and a Müller muscle resection rather than a levator resection will result in a satisfactory correction with less potential for complications.
We believe that Müllerectomies are able to achieve a significant amount of eyelid elevation due primarily to the anatomical relationship between Müller’s muscle and the levator complex as proposed by Werb [7]. Müller’s muscle, through its attachment to the upper border of the tarsus, appears to be the structure most responsible for transmission of the lifting force generated by the contracting levator muscle. In a resting state when the sympathetic nervous system predominates, stimulation of Müller’s muscle controls eyelid position by modifying the effect of levator contraction as it is transmitted to the eyelid. As such, fluctuations in sympathetic tone to Müller’s muscle, as when one is tired or excited, alter the eyelid level, causing either ptosis or lid retraction, respectively. Similarly, Horner syndrome, which is caused by the interruption of sympathetic innervation to Müller’s muscle, is associated with 1–2 mm of ptosis even with a completely normal levator complex. The striated levator muscle is unable to maintain the normal resting position of the eyelid without a normally functioning Müller’s muscle. Although we feel that the importance of the role of Müller’s muscle in eyelid elevation is too frequently underemphasized, at the same time we certainly recognize the major role played by the levator muscle. The effect of Müller’s muscle in voluntary elevation of the lid is entirely dependent on a functioning levator muscle. This is well demonstrated by the situation of a complete third-nerve palsy, which leads to total ptosis regardless of whether Müller’s muscle is maximally stimulated.
Due to the anatomical relationships described above, the instillation of phenylephrine stimulates a normal Müller’s muscle to contract, which in turn leads to elevation of the eyelid. This response to phenylephrine can be duplicated by surgically shortening Müller’s muscle; in essence, the end result is a higher “resting state” upper lid position. Even when poor to fair levator function is present, if the lid responds adequately to phenylephrine, while lid excursions may remain reduced, the upper lid position will nevertheless improve due to “strengthening” of the forces that are transmitted to the tarsus. One of the major advantages of Müller’s muscle surgery is the virtual absence of lagophthalmos postoperatively. While this is of greatest importance for the involutional patient with dry eyes, it is still an advantage in the pediatric age group, although the greatest asset of this internal approach is its high degree of predictability with minimal risk. There is some limitation to this technique, however, in the occasional overhang of excess skin that can obscure the lid fold postoperatively. Of course, a blepharoplasty can be combined with the internal approach if this is recognized as a concern preoperatively.
Müller’s Muscle Surgery
Heinrich Müller first described the sympathetic muscle between the levator and the tarsus in 1858. In 1961, the Fasanella-Servat procedure was first described [31]. This involved an internal approach to the upper eyelid retractors. Beard in 1970 described a modified Fasanella involving the removal of tarsus conjunctiva and Müller’s muscle [32], and Putterman in 1972 published the procedure with the removal of Müller’s muscle and conjunctiva alone.
A number of variations of Müllerectomy procedures have been described over time, but we have predominantly relied on three of these: the Putterman and Werb procedures and a variation of the Fasanella-Servat procedure [7, 33] (see the Surgical Techniques section in this chapter). Putterman’s procedure consists of a Müller’s muscle-conjunctiva resection alone. He states that this is most useful for minimal degrees of congenital ptosis, and we concur, reserving this mainly for those patients with a good response to phenylephrine and only 2–3 mm of ptosis. We have less consistently achieved the desired result in those patients with more severe ptosis, and we attribute this to the fact that Putterman’s procedure involves only a shortening of Müller’s muscle without the advancement gained by a tarsectomy.
Both the Werb and the modified Fasanella-Servat procedures combine a Müllerectomy with an advancement of the muscle secondary to the tarsectomy and thus may achieve a greater amount of eyelid elevation. Although the anatomic purist must certainly dislike the idea of tampering with the tarsus, nevertheless both of these procedures have allowed us to more consistently achieve superior results for many patients and particularly those with larger degrees of ptosis who respond adequately to topical phenylephrine. Despite concerns regarding tarsectomy, many respected surgeons, such as Beard and Gavaris, still advocate its use in certain situations [34].
All three Müllerectomy procedures can be graded according to the patient’s response to the phenylephrine test (Table 22.3). For those patients who achieve a MRD1 that is either higher or lower than desired, both the amount of Müllerectomy and advancement can be adjusted. As to which procedure is used for a given patient, again we reserve Putterman’s procedure for the mildest degrees of ptosis and the Werb procedure and modified Fasanella-Servat for those with more significant ptosis. In recent years, we have favored our variation of the Fasanella-Servat over Werb’s procedure as it is simpler and less time consuming.
In 2012, we presented a consecutive series of 105 cases of modified tarso-conjunctival-Müllerectomies in 96 subjects. The average patient age was 5.82 years with an average follow-up of 6 months. A functional success was defined as a postoperative MRD1 of 3 mm or greater, while a cosmetic success achieved a relative symmetry to the fellow eyelid of 1 mm or less as well. In this series, we achieved a functional success of 97% (102/105 cases) and cosmetic success in 93% (97/105 cases). The average MRD1 improvement was 1.9 mm [35]. Figure 22.24 depicts a good example of a patient before a tarso-conjunctival Müllerectomy, after a drop of phenylephrine 2.5% and after surgery. Note the similarity in appearance of the eyelid after the phenylephrine test after surgery. Figures 22.24 and 22.25 are examples of the modified Fasanella. Figure 22.26 is of a patient who underwent a conjunctival Müllerectomy without a tarsectomy (Putterman approach).
Fig. 22.24
Modified Fasanella-Servat procedure . (a) Preoperative photo of right ptosis. (b) Good response 5 min after the instillation of phenylephrine 2.5%. (c) Six months after surgery
Fig. 22.25
Modified Fasanella-Servat . (a) Preoperative photo. (b) Six months after surgery
Fig. 22.26
Conjunctival-Müllerectomy (Putterman procedure). (a) Preoperative photo. (b) Six months postoperative photo
More recently, a modification to the Müllerectomy was published which included an additional tarsectomy to augment the undercorrection of the preoperative phenylephrine test. This procedure could, perhaps, best be termed the Putterman Plus (Fig. 22.27). In this treatment algorithm, 9 mm of conjunctiva and Müller muscle are resected plus a portion of tarsus with 1 mm of tarsus removed for every 1 mm of undercorrection on the phenylephrine test. Perry et al. reported 117 eyelids (68 patients) with a postoperative symmetry in 58 of 67 patients (87%) and no overcorrections [36]. This technique is exemplified in Fig. 22.28, which depicts a 9-year-old patient with Cornelia de Lange, who was a poor surgical candidate due to developmental delay. A conjunctival Müllerectomy was performed giving this patient a functional improvement in eyelid height with less chin-up position noted on follow-up.
