Schematic representation of eyelid formation in the 7th week of gestation
Representation of the five main facial processes
The development of the eyelid occurs in 5 stages, beginning at week 6 of gestation . Stage 1 is characterized by the development of eyelid folds, which occurs with the migration of ectoderm over the developing lens vesicle. The eyelids fuse over the globe during stage 2 and remain fused from week 8 to month 5 of gestation. During week 8 to month 7 of gestation, stage 3, formation of specialized eyelid structures occurs. The ectoderm on the inner surfaces of the folds will become conjunctiva, and the lacrimal gland will form from an invagination of the conjunctiva. The fusion of the folds contributes to differentiation and development of marginal eyelid structures. Meibomian glands form as the result of ectodermal cords of tissue that invaginate along the eyelid margin and meet the mesenchyme. When the mesenchyme meets the ectodermal cords, the condensed mesenchyme forms the tarsal plates. The cilia and glands of Zeiss and Moll also develop as a result of invagination of ectoderm along the fused margins of the eyelid folds. Orbicularis oculi muscle develops from local mesenchymal tissue.
During stage 4, between 5 to 7 months of gestation, the eyelids start to separate. Eyelid separation begins as an intermittent process, with persistent fine epithelial strands connecting the lid margins until just prior to birth. The separation of the eyelids may occur by a process of apoptosis . Maturation of the meibomian glands with resultant oily secretion and keratinization of the margin epithelium may also play a role in separation of the eyelids [3, 4]. Stage 5 is characterized by structural differentiation and maturation of the eyelids, which is usually complete between month 7 of gestation and birth.
When the orderly sequence of migration and differentiation is disrupted, characteristic patterns of congenital malformation may occur. For example, when the eyelid folds fail to advance and cover the developing globe, complete or partial forms of cryptophthalmos occur . If the eyelid folds fuse, but then fail to separate, forms of ankyloblepharon occur . Colobomas occur when the eyelid folds are interrupted and adjacent tissues are unable to interact to influence growth, maturation, and differentiation. Proposed mechanisms for these disturbances in eyelid development include failure of fusion of the eyelid folds, amniotic bands, alterations in vitamin A metabolism , and abnormal migration of neural crest cells.
Stages of Eyelid Development
Stage 1: Migration of ectoderm over developing lens vesicle to form the eyelid folds
Stage 2: Fusion of the eyelids over the globe
Stage 3: Formation of specialized eyelid structures (meibomian glands, pilosebaceous units, etc.)
Stage 4: Separation of the eyelids
Stage 5: Further structural differentiation and maturation of the eyelids
Anatomy of the Eyelid: Surgical Considerations
When eyelid development proceeds in an orderly fashion, the outcome results in upper and lower eyelids that provide protection, lubrication, and a smooth surface over the eye. The anatomy of the eyelid should be studied in a layered and 3-dimensional fashion to understand the position and interactions of each eyelid component (Fig. 21.3) . In the upper eyelid, the surface epithelium extends from the mucocutaneous junction to the eyebrow. The skin thickens as it approaches the brow. The smooth transition of the skin from the eyelid margin to the eyebrow is interrupted by the eyelid crease. In the non-Asian eyelid, the eyelid crease is formed by anterior fibrous extensions of the levator aponeurosis just above the superior border of tarsus. The position of the eyelid crease provides an external clue to the underlying level of the levator muscle insertion. Anterior to the levator complex is the preaponeurotic fat and the overlying orbital septum which inserts onto the levator aponeurosis and extends superiorly to fuse with periosteum at the arcus marginalis. In the non-Asian eyelid, this insertion of septum onto levator muscle usually occurs 3–10 mm above the superior tarsal border. In the Asian eyelid, the insertion of septum is usually below the superior tarsal border, resulting in a lower eyelid crease and allowing preaponeurotic fat to occupy a lower position in the eyelid.
Diagrammatic representation of the eyelid anatomy . (a) anterior view, (b) sagittal view
Beneath the skin and subcutaneous tissue is the orbicularis oculi muscle , which acts as a circumferential sphincter for the eyelids. The orbicularis muscle is innervated by branches of the seventh cranial nerve and functions to depress the eyebrow and close the eyelids. The orbicularis muscle is divided into pretarsal, preseptal, and orbital components. In the medial canthal region, the fibrous attachments of the lower eyelid preseptal and pretarsal orbicularis muscle divide and wrap around the lacrimal sac. Thus, the coordinated action of the eyelid blink plays a vital role in lacrimal outflow (see Chap. 26). In the lateral canthal region, the fibrous attachments of the orbicularis muscle condense to become a part of the lateral canthal tendon. The most distal edge of the orbicularis in the upper and lower eyelid margins forms the gray line, named the muscle of Riolan. The meibomian gland orifices are located posterior to the gray line along the mucocutaneous junction.
While the levator aponeurosis attaches on the anterior aspect of tarsus, Müller’s superior tarsal muscle , a sympathetically innervated smooth muscle, inserts at the top of tarsus. In an adult, the upper eyelid tarsus is usually between 8 and 10 mm in height. The superior palpebral arcade vasculature runs horizontally between the tarsus and Müller’s muscle. The palpebral conjunctiva, which lines the internal aspect of the eyelid, is posterior to Müller’s muscle and tarsus. The primary retractor of the upper eyelid is the levator palpebrae superioris muscle, which is innervated by the superior division of the oculomotor nerve (cranial nerve III). The levator muscle originates on the lesser wing of the sphenoid bone, just above the annulus of Zinn. It then runs anteriorly through the orbit in close approximation with the superior rectus muscle. Fibrous tissue bands between the levator muscle and superior rectus muscle are responsible for alterations in eyelid position after superior rectus muscle surgery.
The orbital septum is the anterior extension of the periosteum of the orbit. The septum is adherent to periosteum at the arcus marginalis. The septum is a fibrous, multilayered structure that is surprisingly strong in children. It acts as a mechanical barrier to protect the orbit from trauma and infection. The preaponeurotic fat is found behind the orbital septum and is surrounded by a wispy fibrous capsule. In children, the preaponeurotic fat is lighter in color and more “sticky” than in adults. In children, trimming of the fat should be avoided unless the fat interferes with successful closure of an eyelid incision.
Whitnall’s ligament stretches from the lateral to medial orbit and wraps around the levator muscle like a rubber band . The fibrous tissue may function as a suspensory ligament, a check ligament for the levator muscle, and as a pulley to transform the horizontal force of the levator muscle into a vertical force on the eyelid. The levator complex has fibrous attachments that spread out nasally and temporally to form the medial and lateral horns. The lateral horn splits the lacrimal gland into orbital and palpebral lobes and inserts on the lateral orbital tubercle. The medial horn inserts into the posterior arm of the medial canthal tendon.
In contrast to the upper eyelid, the lower eyelid is shorter in vertical dimension and has a shorter distance of excursion. The structures in the lower eyelid are analogous to those of the upper eyelid. The lower eyelid retractors include the capsulopalpebral fascia and the sympathetically innervated inferior tarsal muscle . The capsulopalpebral fascia is analogous to the levator complex in the upper eyelid. It originates from the inferior rectus muscle, wraps around the inferior oblique muscle, and then turns vertically into the eyelid at Lockwood’s ligament (analogous to Whitnall’s ligament). Smooth muscle fibers join the capsulopalpebral fascia on its posterior surface before its insertion onto the inferior tarsal surface. The tarsus has 4 mm of vertical height in the lower eyelid. Similar to the upper lid, the marginal arcade vessels run horizontally between the tarsus and inferior tarsal muscle. A less well-formed peripheral arcade vessel is sometimes present.
Cryptophthalmos , or “hidden eye,” is a rare disorder, characterized by failure of the eyelids to fuse. Isolated cryptophthalmos can either occur sporadically or in an autosomal recessive pattern. Cryptophthalmos can also be associated with two related syndromes, both of which display autosomal recessive inheritance patterns. The first is Fraser syndrome, caused by mutations in FRAS1 and FREM2 genes, characterized by cryptophthalmos, syndactyly, genitourinary tract malformations, craniofacial dysmorphism, orofacial clefting, mental retardation, and musculoskeletal anomalies . The second is Manitoba oculotrichoanal syndrome, caused by a mutation in the FREM1 gene and characterized by cryptophthalmos, triangular growths of hair on the face, a bifid or broad nasal tip, and gastrointestinal anomalies .
Cryptophthalmos is thought to occur as a result of inappropriate formation and migration of the eyelid folds, with ultimate adherence of the eyelids to the ocular surface. In 1969, Francoise proposed a scale, still used today, that divided cryptophthalmos into three general types: complete (total), incomplete (partial), or an abortive/congenital symblepharon variant . Complete cryptophthalmos is the most common form. The initial classification has more recently been expanded to also characterize the congenital symblepharon variant into mild, moderate, and severe based on the degree of eyelid, conjunctiva, and corneal integrity .
Complete cryptophthalmos is characterized by the forehead skin that extends over the globe and onto the cheek without differentiating into upper and lower eyelids (Fig. 21.4). The intraocular structures are grossly disorganized. Incomplete cryptophthalmos is characterized by a skin fold that covers only the medial aspect of the interpalpebral fissure. There may be a coloboma in the upper eyelid, intraocular contents are usually disorganized, and the bony orbit may be contracted . In both complete and incomplete forms, an ocular cyst may be present. In the congenital symblepharon variant, there are usually formed eyelids, but the skin from the upper eyelid is fused with the superior aspect of the cornea or globe, obliterating the superior conjunctival cul-de-sac (Fig. 21.5). In these patients, the cornea may be clear at birth and keratinize postnatally if not adequately lubricated. Alternatively, the cornea may be keratinized at birth due to poor eyelid coverage in utero, resulting in incomplete development of the corneal layers (which occurs at week 8 – month 5 gestation) and exposure of the superior cornea to corneo-toxic renal excretory contents within the amniotic fluid . Adnexal components of the eyelids (i.e., tarsus and meibomian glands) may be absent or rudimentary. It is not uncommon for this type of cryptophthalmos to be associated with nasal defects (including bifid and bulbous nose tip and elevation of the nasal ala), defects of the eyebrow, and a strip of hair extending downward from the scalp .
Complete cryptophthalmos . (a) The surface epithelium passes smoothly from the forehead to the cheek. Brow cilia are present but distorted. There is continuity between the lateral eyebrow and the scalp hair. (b) With positive ERG findings, an attempt was made to create eyelids and open a pupillary axis. A total reconstruction of the anterior segment was done using a corneoscleral graft. There was no lens present. Oral mucous membrane was used to graft the inner surfaces of the skin that had been separated from the globe. (c) Surgery was successful in creating rudimentary eyelids and opening a palpebral fissure, but this did not result in useful vision
Partial cryptophthalmos . (a) The partial cryptophthalmos in this patient shows surface epithelium confluent with the ocular surface on the medial aspect of the globe. Also note the absence of the medial eyebrow and the lateral displacement of the brow cilia. (b) The eyelid is reconstructed using the surface epithelium for the anterior lamella and a mucous membrane graft to replace the palpebral conjunctiva. Since the eye had no potential for visual function, the globe is covered by an ocular prosthesis
Prior to surgical intervention, the visual potential of the eye(s) should be determined. Underlying ophthalmic abnormalities, usually including corneal and anterior segment dysgenesis, are not always apparent. Ultrasonography can be useful in assessing the organization of intraocular contents. Electrophysiologic evaluation with electroretinogram (ERG) and visual evoked potential (VEP) can be helpful in evaluating the visual potential of an affected eye. Eyelid sharing procedures for reconstruction are usually avoided when the eye may have useful vision. Computerized tomography (CT) can evaluate the bony orbital structures but should not be pursued unnecessarily in children given the exposure to radiation. A history of consanguineous parents can be ascertained, and, in children with other anomalous features (i.e., syndactyly), evaluation by a medical geneticist is warranted for screening of associated systemic conditions, such as Fraser or Manitoba oculotrichoanal syndrome.
Eyelid and ocular surface reconstruction must include consideration of the four major structural and functional components of the eyelids: mucus membrane for lubrication and a smooth posterior surface, tarsus for eyelid rigidity, eyelid retractor and protractor muscles for eyelid opening and closing, and skin to cover the external surface. All four functional components need to be present for adequate reconstruction, and many approaches have been described.
In partial cryptophthalmos, the surgeon may need grafts or flaps to replace the missing portions of the eyelid and conjunctiva. In the areas where the eyelid and globe are fused, caution should be taken because the surface epithelium is often continuous with the corneal surface, and this surgical plane is difficult to separate. If the eye is to be preserved, the surgeon needs to be prepared to graft the cornea when there is inadvertent penetration of the globe. The posterior lamella of the eyelid can be reconstructed, if necessary, with mucous membrane from the mouth or nose, cartilage from the ears or the nose, or allogeneic materials such as alloderm . The anterior lamella can be reconstructed with free skin grafts or local sliding or rotational skin flaps [13–15]. Since children have limited eyelid laxity, these reconstructive approaches are more successful if they can be deferred until an older age. However, if corneal exposure is a concern or visual rehabilitation is a priority, skin expanding techniques can be employed with the general plastic surgery team to make more available skin for reconstruction. Eyebrows can be remodeled using hair transplant techniques or tattooing.
Attempts at visual rehabilitation can be made in all forms of cryptophthalmos, although they are generally more successful in the incomplete and congenital symblepharon variants. The results of surgical reconstruction for complete cryptophthalmos have not been encouraging. Overall, visual potential is poor, and the rationale for surgical correction is usually to achieve better cosmesis with good lid support for possible future placement of an ocular prosthesis. None of the tissue substitutes for the posterior lamella contain the elements of normal tear secretion, and maintaining a clear corneal surface after eyelid reconstruction becomes a constant struggle. As in other forms of ocular dysgenesis with limited or absent visual function (i.e., microphthalmia), for more severe cases of partial cryptophthalmos, an oral mucous membrane graft over the cornea can be considered, allowing for an ocular prosthesis to be worn comfortably while also providing better overall cosmesis .
Clinical Anophthalmia and Microphthalmia
Congenital anophthalmia and microphthalmia (A/M) and coloboma are an interrelated group of congenital abnormalities that likely have an underlying genetic basis. Together, these disorders account for 15–20% of severe visual impairment in children worldwide [17, 18]. Microphthalmia and anophthalmia have an estimated prevalence of 1 per 7000 and 1 per 30,000 live births, respectively . SOX2 and OTX2 gene mutations, which cause lens induction failure, account for up to 60% of bilateral cases of severe microphthalmos and clinical anophthalmos [19, 20] (see Chap. 39). Environmental factors such as gestationally acquired infections, maternal vitamin A deficiency, X-ray exposure, and thalidomide exposure may also play a role . Lower socioeconomic class and consanquinity may also be risk factors for the development of microphthalmia .
Congenital anophthalmia is rare and refers to a complete absence of ocular tissue. It occurs when there is a failure in the optic vesicle to bud or early arrest of its development with subsequent degeneration. Failure of optic vesicle budding may be “primary,” with involvement of ocular tissue only, or “secondary,” with complete suppression of the forebrain. The latter condition is not compatible with life. Clinical anophthalmos is a more appropriate term, used to describe the clinical absence of a visible eye, although rudimentary eye structures are often present radiographically. In contrast, microphthalmia is defined by the presence of a small, often disorganized eye, with a corneal diameter less than 10 mm and an axial length less than 20 mm. It is thought to result from incomplete invagination of the optic vesicle into the optic cup or from defective closure of the embryonic fissure, sometimes leading to colobomatous microphthalmos with uveal coloboma or colobomatous cyst .
Clinical anophthalmia and microphthalmia may occur in isolation or in association with other systemic abnormalities related to errors in the development of the first and second branchial arches (which later contribute to most structures of the head and neck) during weeks 4–6 of embryogenesis. Conditions that result from abnormalities during this phase in gestational development are referred to as “oculo-auricular-vertebral spectrum” disorders . Many patients with clinical anophthalmia or microphthalmia have associated systemic conditions that fit into this spectrum of disorders.
Clinical anophthalmia and microphthalmia can occur unilaterally or bilaterally. The smaller the eye or eye remnant, the more severely retarded the growth of the orbit and eyelids. Abnormalities of the eyelid occurring in association with microphthalmia include eyelid coloboma, decreased horizontal and vertical palpebral fissure length, decreased conjunctival surface area, and relative shortening of the posterior lamellae with or without congenital entropion . Although the adnexal structures of the eyelids are present, they are commonly decreased in size and number compared to the normal eyelid. Changes in bone growth can result in a decreased midline to inner canthal distance, maxillary hypoplasia, a posteriorly displaced lateral orbital rim, decreased horizontal brow length, and a low supraorbital ridge.
Ocular pathology can include limbal dermoids, coloboma of the iris or retina, cataract, Duane’s retraction syndrome, decreased corneal sensation (trigeminal nerve abnormality), and optic nerve hypoplasia . In microphthalmia, glaucoma may occur in the setting of a short axial length and resultant chronic angle closure. Acute angle closure and pupillary block can also occur from a disproportionately large lens in a cramped anterior chamber . In unilateral cases of microphthalmos, some of these associated ocular findings can also be present in the contralateral eye . Over 50% of cases may be associated with systemic abnormalities, which can involve the central nervous system, face (cleft lip or palate, hemifacial microsomia, facial hypoplasia, micrognathia), skeletal system (anomalous limbs), ear (preauricular skin tags, deafness), heart (ventricular septal defects, tetralogy of Fallot, coarctation of the aorta), genitourinary system, and gastrointestinal system .
All neonates born with microphthalmia or anophthalmia should be promptly evaluated by the neonatal team or pediatrician to check for systemic manifestations of the “oculo-vertebral-auricular spectrum.” If there are severe ocular abnormalities, evaluation by an ophthalmologist should occur within the first 2 weeks of life. In unilateral cases, it is important to examine both eyes, since the fellow eye can also be affected. In clinical anophthalmia, an ocular ultrasound can be helpful to look for eye structures. In microphthalmia, ultrasound can be useful in measuring baseline axial length in the clinic setting. Magnetic resonance imaging (MRI) or CT (if MRI not available) should be performed to evaluate the bony orbit outline and to check for intracranial abnormalities. Similar to cryptophthalmos, VEP and ERG can be useful for examination of visual potential. Genetic screening is useful and especially warranted if a clinical syndrome is suspected.
Initial management decisions in microphthalmia are generally guided by whether the eye has visual potential. In some cases, the answer is apparent when the ocular remnants are so rudimentary that there is no potential for useful vision. In other cases, however, it can be difficult to judge the visual potential of a microphthalmic eye. Since treatment with expanding conformers or orbital volume augmentation may disrupt the visual pathway, the decision about visual potential must be considered prior to therapeutic intervention. If good vision is possible, and even very rudimentary vision may be valuable in cases of bilateral microphthalmos, then some reconstructive steps of the orbit and eyelids may be modified or postponed to prevent amblyopia .
The normal eye of a child at birth is about 70% of its adult size. However, the face is much smaller at birth and only reaches 40% of its adult size by 3 months. Over the first 2 years of life, the face grows to about 70% of its adult dimensions . In severe microphthalmia and anophthalmia, growth of the orbit, fornices, and eyelids is retarded as a result of reduced orbital volume and growth stimulation. Early intervention is important to avoid permanent structural abnormalities that may compromise use of an ocular prosthesis later in life. Expansion of the orbit and socket should be instituted as early as possible to stimulate growth. Initially, the physician should evaluate the size and shape of the socket. If the socket is sufficient to hold a conformer, the ocularist is consulted to begin soft tissue expansion with orbital conformers. The success of the conformer in altering eyelid shape and growth is best achieved when started at the youngest ages. Conformers are clear, which can facilitate visual development in the case of a positive VEP or ERG. Growth can be monitored by assessing clinical symmetry of the lids and brow and by following serial imaging measurements.
When the socket size is insufficient to hold a conformer, mucosal grafting with buccal mucosa or hard palate can be used to expand the socket surface area. In unilateral cases, the physician can monitor growth by comparing eyelid measurements to the contralateral (if normal) side or pediatric growth charts . Despite placement in an anterior position, progressively increasing size conformers will gradually create space in the posterior socket in addition to stretching the eyelids. When the posterior space becomes large enough that it is difficult to pass the conformer through the palpebral fissure, orbital volume augmentation is performed. This typically occurs around 12 months of age. Synthetic materials or autogenous dermis and fat may be used (Fig. 21.6) . The dermis portion of the dermis fat graft may also be used to enlarge the socket surface area. Conjunctiva will grow and cover the dermal surface when it is sewn over the edges of the dermis fat graft. Asymmetry in the vertical palpebral fissure may be improved by ptosis procedures, but augmentation of the horizontal palpebral fissure remains a surgical challenge. Releasing the lateral canthal tendon does not typically result in a cosmetically pleasing eyelid, limits future eyelid stretching due to scarring at the canthal angle, and should generally be avoided.
Congenital microphthalmia . The condition was treated initially with progressively enlarging conformers followed by a dermis fat graft to augment the orbital volume. (a) Age 4 months at time of presentation. (b) Age 12 months, after treatment with increasing size conformers, the posterior socket has enlarged, creating room for volume augmentation. Because the socket size has outpaced the palpebral fissure opening, the current conformer can rotate within the socket. This is a signal to begin volume augmentation. (c) The conjunctiva is opened and blunt dissection used to create space for the dermis fat graft. (d) A dermis fat graft is harvested from the buttock. (e) Age 20 months with dermis fat graft and new prosthesis
Hard palate mucosa is sometimes of value and may be harvested from the roof of the mouth to augment the socket surface area or to provide stability to the eyelids (see Chap. 4). The roof of the mouth is inspected, and the junction between the hard and soft palate is identified (Fig. 21.7). There is a color change in the mucosa as well as the difference in the palpable firmness of the palate structure. Harvesting is performed anterior to the junction. There is a central ridge across the arch of the hard palate where the mucosa is thin and firmly attached to the underlying periosteum. This area is avoided. The vascular supply to the palate enters through the incisive foramen just behind the two front teeth and through the palatine foramina, which are located laterally at the junction of the hard and soft palate. Graft harvesting in these areas is avoided. Just behind the incisive foramen, there are horizontal rugae in the mucosa. This rough area is usually not appropriate for grafting. The hard palate near the roots of the teeth heals very slowly, and this area is also avoided. The flattened area of hard palate between the alveolar ridge and the central arch is the appropriate area for graft harvesting.
Hard plate mucosal grafts . (a) Hard palate mucosal grafts should be harvested so as to avoid the gingiva, the palatine raphe, the nasopalatine foramen, and the greater palatine foramen through which pass corresponding nerves and vessels. (b) The graft site can be lightly cauterized for hemostasis as needed
The mucosa is infiltrated with local anesthesia and epinephrine. The local anesthesia will help with postoperative pain and the epinephrine for hemostasis. Marcaine 0.25% with 1/200,000 epinephrine is one choice of local anesthetic in children. About 1–2 ml of solution is injected. The hard palate will blanche with injection. The graft is marked, and then a No. 15 blade scalpel is used to incise the mucosa. Using the No. 15 blade scalpel, Westcott scissors, or dissection unit, the graft of mucosa is harvested leaving the underlying fat and periosteum intact. Cautery is used for hemostasis, and a strip of gelfoam soaked in thrombin is sewn over the areas of mucosal defect. Chromic gut or Vicryl suture (Ethicon) may be used. In the older child, a preformed palatal stent may be ordered from the dentist. The stent protects the healing palate from abrasion and decreases postoperative discomfort. The palate graft is then sewn into position in the socket or the eyelid using a resorbable suture such as 5-0 or 6-0 Vicryl. The hard palate mucosa is a versatile grafting material that simultaneously provides a mucosal surface as well as tissue rigidity. Since there is very little shrinkage of the hard palate mucosa, the graft is harvested to match the area of the defect. The first 3–6 weeks after surgery, the palate will sometimes shed white keratin material. This will stop after 3–4 weeks. The hard palate is a good surface replacement for the socket or the lower eyelid, but its use in the upper lid is limited because the irregular surface may cause corneal epithelial defects.
In cases of severe microphthalmia or anophthalmia, more aggressive orbit expansion must be undertaken. This has historically been done with frequent visits to the operating room using progressively larger acrylic socket expanders. More recently, hydrophilic expanders have successfully been used in the outpatient setting with good functional and cosmetic results . These expanders, which are available in different sizes, can be placed in the socket with suture or glue tarsorrhaphy of the eyelids (see Chap. 39). Placement of a glue tarsorrhaphy, in particular, allows this to easily be done in the office. The average number of exchanges of hydrophilic implants is usually 2–3 times before age 2. Once the child is around 1 year of age, if sufficient space has been achieved, a dermis fat graft can be considered to promote continued orbital expansion.
It can be tempting to remove a non-seeing eye and place a dermis fat graft or an orbital implant at an early age. However, if possible, even a severely microphthalmic eye should be left in place since it will provide some stimulus to eyelid and orbital growth . Static orbital implants are usually avoided, as they need to be changed in the operating room between 5 and 7 times before puberty and are associated with high incidences of wound dehiscence and implant extrusion . Rarely, bone growth may be unresponsive to conformer expansion, and osteotomies and interpositional bone grafting can be considered (Fig. 21.8) .
Anophthalmia and hypoplasia . This patient had attempts at right socket expansion with bony and soft tissue hypoplasia. (a) At 3 years of age, this patient had a small socket unable to retain a prosthesis. (b) CT scan shows the relative bony hypoplasia on the right side. (c) The patient’s appearance at 5 years of age following craniofacial expansion of the bony orbit. (d) The CT scan shows cranial bone grafts placed along the lateral orbital rim and the superior orbital rim to help improve facial symmetry
In patients with microphthalmia and colobomatous cyst, gradual orbit expansion can be achieved by taking advantage of the natural expansion of the cyst from accumulation of fluid and/or glial tissue . If enlargement of the cyst is too rapid, a needle decompression can be performed, although this should be cautiously done because there is often a direct connection between the cyst and the eye or brain. However, fluid usually will re-accumulate. Generally, by age 5, the orbit has reached 90% of its adult dimensions, and the eye and cyst can then be removed with placement of a more cosmetically acceptable ocular implant and prosthesis prior to the start of school . Family members may need reassurance that this is the best approach since the appearance of microphthalmia with cyst can be discouraging. Prior to any surgical intervention, an MRI should be performed to assess the cyst size and whether there is any connection to the brain.
After initial successful socket expansion, the prosthesis and socket should be followed at least yearly for the first 5 years of life. As mentioned previously, microphthalmic eyes are at risk for angle closure glaucoma, which may cause pain. Children with chorioretinal coloboma are at increased risk of retinal detachment, and precautions should be reviewed with parents. Polycarbonate glasses should be prescribed for refractive error and protection. Families and patients should be connected with vision support services soon after diagnosis to facilitate the best potential emotional and intellectual development of the child. A close relationship with an ocularist is essential.
Eyelid coloboma describes an anatomic disruption or void along the eyelid margin with an overall prevalence of 0.7 per 10,000 births (Fig. 21.9) . It can occur sporadically or be associated with other conditions such as Fraser syndrome (Fig. 21.4), Goldenhar syndrome (Fig. 21.10), and Treacher Collins syndrome where there may be a true notch or merely a drooping of the lateral lower lid often termed a pseudocoloboma (Fig. 21.11), CHARGE syndrome , Manitoba oculotrichoanal syndrome, and other rare variants. The exact prevalence of a sporadic coloboma is unknown . In a true coloboma, there is an actual discontinuity in the eyelid margin. Pseudocolobomas occur in the eyelids when continuity in the superficial ectoderm of the eyelid margin is maintained but there is failure in development of the underlying mesenchymal tissues including orbicularis muscle and bone. Examples of this can be seen in the facial microsomias as well as in Treacher Collin Syndrome.
Eyelid coloboma in the most common location between the junction of the middle and inner one-third of the upper eyelid
Examples of the periocular manifestations of Goldenhar syndrome . (a) Preauricular skin tags; (b) limbal dermoid; (c) dermolipoma, corectopia; (d) upper eyelid coloboma
Treacher Collins syndrome with an eyelid pseudocoloboma
Embryologically, a coloboma may result from an error in ectodermal or mesodermal migration. Mechanical forces, such as amniotic bands, may also cause compressive tissue destruction of the developing eyelid. In the case of Goldenhar syndrome , the presence of a limbal dermoid may exert pressure on the eyelid, resulting in a focal failure of eyelid development. Abnormalities in the movement of fetal growth plates during embryogenesis can also explain variation in coloboma location. As such, colobomas may be seen in conjunction with other clefting phenomena or as part of a craniofacial syndrome. The system described by Tessier et al.  (see Chap. 38) can be helpful in characterizing colobomatous defects (Fig. 21.12). Colobomas vary in size and location but have some characteristic locations. In order of descending frequency, colobomas occur at the junction of the middle and inner one-third of the upper eyelid (Fig. 21.9), the central upper eyelid, the junction of the lateral and middle one-third of the lower eyelid, and at the junction of the middle and inner one-third of the lower eyelid .
Tessier clockface. The location of facial clefts can be described based on the geographic location of the cleft. This is derived from Tessier’s numeric naming diagram. (a) Soft tissue defects. (b) Underlying bony defects
While colobomas associated with Goldenhar syndrome, Fraser syndrome, or Treacher Collins syndrome are often bilateral, isolated simple colobomas are strictly unilateral, have no associated systemic signs, and do not usually present with significant corneal pathology. The size of the colobomatous lid defect may be overestimated in the clinical setting because of tissue elasticity and orbicularis muscle tone that pulls the colobomatous edges to either side. Associated ocular findings can include limbal dermoid in the case of Goldenhar syndrome, microphthalmos, iris coloboma, and osseous facial clefts. Facial abnormalities can include loss of ipsilateral eyebrow hair, a poorly formed supraorbital rim, cleft and lip palate, and a bifid nose. Additional clinical features of Goldenhar syndrome, Fraser syndrome, and Treacher Collins syndrome are described in Chap. 38 and elsewhere .
The pediatrician or neonatal team should be involved in the initial evaluation of a child with an eyelid coloboma to screen for syndromes. When applicable, referral to a geneticist for screening and counseling is warranted. A careful ophthalmologic exam should be performed, with special attention given to the condition of the cornea.
Appropriate management and protection of the ocular surface is crucial when dealing with eyelid coloboma. If the corneal epithelium is jeopardized, initial management should consist of ocular surface lubrication and, when necessary, occlusive dressing with plastic wrap. In the case of a small colobomatous defect (<25%) without evidence of keratopathy and a good Bell’s phenomenon, watchful observation is often favored until 1–2 years of age prior to entering a preschool environment where considerations regarding appearance begin to emerge as a factor in psychosocial development . Even large defects may be initially managed in this fashion if the cornea is adequately protected. However, lubrication with ointment and occlusion has the potential to create amblyopia, and this must be carefully monitored.
Location of Eyelid Colobomas (Most Common to Least Common)
Junction of the middle and inner one-third 1/3 of the upper eyelid
Central upper eyelid
Junction of the lateral and middle one-third 1/3 of the lower eyelid
Junction of the middle and inner one-third 1/3 of the lower eyelid
Repair of Upper Eyelid Colobomas
The technique used to repair a defect can be planned preoperatively based on its size. In an infant, small colobomas (<25% eyelid defect) can be closed primarily by excising the epithelial edges of the coloboma to create a wedge- or pentagon-shaped eyelid defect (Fig. 21.13). The edges of the tarsus are pulled together with interrupted 5-0 Vicryl sutures which are not tied until the eyelid margin has been repaired. Interrupted 6-0 or 7-0 Vicryl sutures are placed in three locations across the margin defect: lash line, gray line, and mucocutaneous junction. The distance from the entry site of the suture to the margin edge should be approximately 2 mm on either side, and the suture depth should be about 2–3 mm. After the tarsal and margin sutures are tied, the orbicularis and skin are closed in one or two layers. 6-0 fast-absorbing gut sutures are preferable for skin closure, unless more tension on the wound requires 6-0 Vicryl for closure (Fig. 21.14).
Coloboma repair. (a) Upper eyelid coloboma. (b) The margins of the coloboma are trimmed to remove epithelium. (c) A lid crease incision and a lateral canthal incision allow approximation of the margins of the coloboma. (d) Interrupted 5-0 Vicryl sutures re-approximate the tarsus, and 6-0 or 7-0 Vicryl sutures are used to close the eyelid margin. All sutures are positioned before any are tied. (e) The ends of the margin sutures are pulled up and tied into one of the vertical skin sutures. (f) Skin closure completes the repair, using 6-0 plain gut suture
Goldenhar syndrome . (a) Upper eyelid coloboma at age 1 week. (b) Preauricular appendages. (c) Two weeks postop at age 6 months following sliding flap repair with levator advancement. (d) Three months postop at age 9 months
For an eyelid defect >50% of the eyelid margin, tissue will need to be borrowed from other locations. Free tarsal or conjunctival grafts may be obtained from the upper lids; hard palate mucosa can be used in the lower lids; tarsus can be split in the upper eyelid to create a tarsal conjunctival flap; and skin grafts can be harvested from the retroauricular or supraclavicular areas, the upper eyelid, or from penis foreskin. Eyelid sharing procedures can be used in older children but may create amblyopia in younger children. However, when faced with uncontrolled corneal exposure and possible corneal ulceration, eyelid sharing techniques followed by aggressive amblyopia therapy may be necessary. In such instances, division of the transposed eyelid may be performed after 2 weeks rather than the recommended 4–6 weeks. In the upper eyelid, increased horizontal traction at the time of coloboma repair will sometimes create an upper eyelid ptosis. Advancement of the levator aponeurosis in the upper eyelid is sometimes performed in conjunction with coloboma repair to help prevent this problem.
In the older child or in a desperate situation, a Mustarde rotational transposition flap from the opposing eyelid can be used to close the defect and provide an anatomically matched eyelid margin (Fig. 21.15). This technique results in a cosmetically superior eyelid with an intact lash line, but the lashes are not certain to survive. Also, one must realize that the lashes of the lower eyelid are shorter and more dispersed than those of the upper eyelid. Nevertheless, with a broad base, the appearance of this upper eyelid reconstruction may be best in select cases. It is usually reserved for the older child or an infant with no potential for useful vision (Fig. 21.16). Again, with large skin needs, a team approach with plastic surgery can be employed where perioperative skin stretching is performed and used for subsequent eyelid reconstruction.
Coloboma repair by the Mustarde rotating transposition flap technique from opposing lid. (a) Upper eyelid coloboma and marking of the pedicle flap in the lower eyelid. (b) The flap is rotated into the upper eyelid defect. (c) The flap is sewn into position and the lower lid defect pulled together. The flap is left in place for 4–6 weeks to allow for revascularization and then divided from the lower eyelid
Coloboma repair with lid-sharing Mustarde flap. (a) Upper eyelid coloboma in a 6-month-old with associated anterior segment dysgenesis, congenital glaucoma, and buphthalmos. (b) With no hope for functional vision, a Mustarde flap repair is performed at age 14 months. (c) The same patient at age 14 years with a cosmetic shell in place
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Repair of Lower Eyelid Colobomas
As presented in box above , lower eyelid colobomas are less common than those occurring in the upper eyelid; and the least common are those involving the medial third of the lower lid. As discussed previously, the eyelid deformity most often found in the lower eyelid in Treacher Collins syndrome is more aptly termed a “pseudocoloboma,” because there is continuity of the anterior lamella but discontinuity of the posterior lamella . Occasionally, however, true colobomas with an eyelid notch and absence of cilia may also occur. Although the pseudocoloboma presents less danger to the ocular surface, successful cosmetic repair is challenging because the problem is not just the position of the lateral canthal tendon but also an absence of vertical and horizontal eyelid soft tissue. Repositioning of the lateral canthus and lower eyelid can be used with differing techniques based on the severity of the deformity. Rarely, simple repositioning of the lateral canthal tendon may be successful (Fig. 21.17). In more severe cases, hard palate or ear cartilage grafts have been used to support and lengthen the eyelid, and additional strength can be placed on the lateral canthal fixation with wire passed through drill holes in the lateral orbital rim. Ear cartilage is less desirable even when scored to gain more pliability. The hard palate graft is preferable or even use of other donor spacer materials such as alloderm.
Lateral canthoplasty . (a) Repair of the lower lid position begins with a lateral canthal skin incision. (b) The incision is completed to full thickness with a scissors. (c) The inferior limb of the lateral canthal tendon is released from its periosteal attachment. (d) The lid is pulled up into position to judge where the cut lid margin should be reattached to the lateral orbital rim. (e) The cut margin of the lower lid is secured with a double-armed 4-0 Vicryl suture that passes through the tarsal strip. Both ends of the suture are then passed through the lateral orbital rim periosteum. Alternatively, the suture may be passed through drill holes placed through the rim bone. (f) The lateral canthal angle is reformed with a suture passed from gray line to gray line in a buried fashion. This suture helps to keep a symmetric relationship between the edges of the lid margin. The skin is then closed with a resorbable suture
For more extensive lower lid defect, particularly those associated with craniofacial clefting problems, a coordinated, multidisciplinary approach may be needed. Fig. 21.18 demonstrates such a complex repair. A decision was necessary regarding the primary need for reconstructive flaps in a child with partial cryptophthalmos, lower lid coloboma, microphthalmia, and clefting of both the lip and palate. Because the eye had no chance for useful vision, the concern for feeding issues due to the cleft lip and palate took preeminence in designing the flaps. Once these were outlined, it was possible to turn to solutions for the lower lid coloboma and the microphthalmic globe with an attached symblepharon. It was possible to design a rotating cheek flap for the lid repair and a protective conjunctival cover graft to permit use of a conformer shell and eventual cosmetic prosthetic shell, thus achieving both functional and appearance benefits.
Lower lid coloboma with partial cryptophthalmos and microphthalmia. (a) Microphthalmic globe and coloboma of probable amniotic band etiology with partial cryptophthalmos symblepharon in 1-year-old child. (b) Cleft lip and palate with flaps for repair outlined. (c) Mobilization of lip flaps for repair. (d) Dissection of Mustarde rotating cheek flap. (e) Cheek flap rotated into position. (f) Six months postoperative appearance. (g) 18 months postoperative appearance with successfully fitted ocular prosthesis