Optic nerve abnormalities Because the synostosed cranial vault is unable to expand as the brain grows, the intracranial contents become crowded, elevating intracranial pressure (ICP). The risk of hindrance to brain growth is much greater when multiple sutures are fused. Elevated ICP can result in papilledema (discussed in Chapter 26), and chronic papilledema can lead to optic atrophy and subsequent vision loss. Optic atrophy may occur with or without antecedent papilledema. Hydrocephalus is another cause of elevated ICP and occurs in up to 40% of patients with Apert, Crouzon, and especially Pfeiffer syndromes. The severe midface retrusion that these conditions produce may cause breathing problems and sleep apnea. Idiopathic intracranial hypertension secondary to sleep apnea can also cause elevated ICP and papilledema. Because children with elevated ICP may not complain of a headache, young patients with multiple fused sutures should be examined yearly or biyearly.
Optic nerve edema and/or atrophy can also occur secondary to compression from optic nerve foramen synostosis. This is rare in patients with craniofacial syndromes but has been described.
Ocular adnexal abnormalities Common ocular adnexal abnormalities include orbital hypertelorism, telecanthus, abnormal slant of the palpebral fissures secondary to superior displacement of the medial canthi, ptosis, and nasolacrimal abnormalities such as duct obstruction and punctal anomalies. Epiphora is a common finding in patients with craniosynostosis and may be secondary to nasolacrimal duct obstruction, poor blink secondary to proptosis, obliquity of the palpebral fissures, or ocular irritation from corneal exposure.
Surgical management of craniosynostosis
Reconstructive surgery for severe craniofacial malformation is frequently extensive and involves en bloc movement of the facial structures. The status of the visual system should be documented preoperatively and monitored postoperatively, with appropriate treatment as indicated.
In many centers, a craniofacial team—composed of facial plastic surgeons, neurosurgeons, ophthalmologists, and oral surgeons—collaborates to determine the timing of the reconstructive surgery. Procedures that involve moving the orbits may significantly change the degree or type of strabismus, thereby influencing the choice of strabismus surgery. Because of this, deferring treatment of strabismus until craniofacial surgery is completed may be appropriate.
Nonsynostotic Craniofacial Conditions
Many craniofacial syndromes do not involve synostosis. A few of particular importance to the ophthalmologist are discussed in the following sections.
Anophthalmia
Anophthalmia (anophthalmos) is the absence of tissues of the eye. Anophthalmia is the most severe phenotypic expression of a spectrum of abnormalities that includes typical coloboma and microphthalmia (see Chapter 20). These conditions may be isolated, but they are frequently associated with other congenital anomalies. The genetic and environmental factors associated with these ocular abnormalities are complex and not fully defined. As with severe forms of microphthalmia, anophthalmia is associated with hypoplastic orbits and eyelids. Various techniques have been utilized for orbital expansion, and the best results are achieved with early treatment.
Branchial arch syndromes
Branchial arch syndromes are caused by disruptions in the embryonic development of the first 2 branchial arches, which are responsible for formation of the maxillary and mandibular bones, the ear, and facial musculature. The best known of these syndromes is the oculoauriculovertebral spectrum
(OAVS), which includes hemifacial microsomia, Goldenhar syndrome, and Treacher Collins syndrome. There is no firm agreement about the nomenclature relating to this condition, but most believe that hemifacial microsomia is a forme fruste of OAVS. Patients with OAVS may have vertebral abnormalities such as hemivertebrae and vertebral hypoplasia. They may also have neurologic, cardiovascular, and genitourinary abnormalities. Most cases are sporadic, but there are rare familial cases.
Goldenhar syndrome Goldenhar syndrome is a more severe presentation of OAVS. Patients with Goldenhar syndrome have hemifacial microsoma (unilateral or bilateral), as well as characteristic ophthalmic abnormalities (Fig 18-8). Most cases are sporadic.
Figure 18-8 Goldenhar syndrome with hemifacial microsomia. Patient has facial asymmetry, a hypoplastic left ear (microtia), an ear tag near the right ear, epibulbar dermolipoma in the left eye, and esotropia. Patient also has Duane retraction syndrome, left eye.
Epibulbar (limbal) dermoids and dermolipomas are characteristic ocular signs of Goldenhar syndrome. Dermolipomas (also termed lipodermoids) usually occur in the inferotemporal quadrant,
covered by conjunctiva and often hidden by the lateral upper and lower eyelids. Epibulbar limbal dermoids are reported more frequently than dermolipomas and can be bilateral (approximately 25% of cases). They occasionally impinge on the visual axis but more commonly interfere with visual acuity by causing astigmatism and anisometropic amblyopia. Eyelid colobomas may occur. Other abnormalities include microphthalmia, cataract, and iris abnormalities. Duane retraction syndrome is more common in patients with Goldenhar syndrome than in the general population.
Treacher Collins syndrome Treacher Collins syndrome (mandibulofacial dysostosis) is due to abnormal growth and development of the first and second branchial arches, which give rise to underdevelopment and even agenesis of the zygoma and malar eminences. The cheeks and lateral orbital rims are depressed, and the palpebral fissures slant downward because of lateral canthal dystopia (Fig 18-9). Pseudocolobomas (and, uncommonly, true colobomas) are found in the outer third of the lower eyelids. Meibomian glands may be absent. The cilia of the lower eyelid may also be absent, medial to the pseudocoloboma. The ears are malformed and hearing loss is common. The mandible is typically hypoplastic, leading to micrognathia. Intelligence is normal. The syndrome is inherited in an autosomal dominant fashion and displays variable expression. Most affected patients have a mutation in the TCOF1 gene.
Figure 18-9 Treacher Collins syndrome (mandibulofacial dysostosis). Note downward slant of palpebral fissure, low-set abnormal ears, notch or curving of the inferotemporal eyelid margin, and maxillary and mandibular hypoplasia. (Reproduced
with permission from Peyman GA, Sanders DR, Goldberg MF. Principles and Practice of Ophthalmology. Philadelphia: Saunders; 1980:2411.)
Pierre Robin sequence
The Pierre Robin sequence (also anomaly, deformity) is characterized by respiratory problems, micrognathia, glossoptosis, and cleft palate. The sequence is a frequent finding in Stickler syndrome. Associated ocular anomalies include retinal detachment, microphthalmos, congenital glaucoma, cataracts, and high myopia.
Fetal alcohol syndrome
Fetal alcohol syndrome (FAS) is a craniofacial condition caused by in utero exposure to ethanol. It is characterized by prenatal and postnatal growth retardation, central nervous system and craniofacial abnormalities, and intellectual disability.
The classic ocular features of FAS are short palpebral fissures, telecanthus, epicanthus, ptosis, microphthalmos, and esotropia (Fig 18-10). Anterior segment dysgenesis, optic nerve hypoplasia, and high refractive errors have been reported. Fifty percent of children with this underdiagnosed syndrome have some form of visual impairment.
