Ocular manifestations of craniosynostosis

Craniosynostosis is a group of rare inherited disorders characterized by premature closure of the cranial sutures in combination with severe orbital abnormalities.

The two most common pathologies in which craniosynostosis occurs are: Crouzon syndrome, Apert syndrome.

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Crouzon syndrome

Crouzon syndrome is primarily formed by premature closure of the coronal and sagittal sutures. Heredity is autosomal dominant, but in 25% of cases there may be a fresh mutation.

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Eye manifestations

• Exophthalmos due to a shallow orbit is the most noticeable sign. It develops secondarily due to growth retardation of the maxilla and cheekbone. In severe cases, the eyeballs are dislocated and lie in front of the eyelids.
• Hypertelorism (wide distance between orbits).
• V-shaped exotropia and hypertropia.
• Vision-threatening complications include exposure keratopathy and optic neuropathy due to compression of the optic nerve at the optic foramen.

Pathology of the eyeball: aniridia, blue sclera, cataract, lens subluxation, glaucoma, coloboma, megalocornea and optic nerve hypoplasia.

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Systemic disorders

• Shortening of the anteroposterior dimension of the head and a wide skull due to premature closure of the sutures.
• Hypoplasia of the midface and a curved nose ('parrot beak'), giving the face a 'frog-like' appearance.
• Prognathism of the lower jaw.
• Inverted V-shaped sky.
• Acanthokeratoderma.

Apert syndrome

Apert syndrome (acrocephalosyndactyly) is the most severe of the craniosynostoses and may involve all cranial sutures. Inheritance is autosomal dominant, but most cases are sporadic and associated with advanced parental age.

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Eye signs

• Shallow orbits, exophthalmos, and hypertelorism are usually less pronounced than in Crouzon syndrome.
• Exotropia.
• Anti-Mongoloid eye shape.
• Vision-threatening complications include failure of the eyelids to cover the cornea and optic nerve atrophy.

Pathology of the eyeball: keratoconus, subluxation of the lens and congenital glaucoma.

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Systemic signs

• Oxycephaly with a flat occiput and steep forehead.
• Horizontal notch above the supraorbital ridge.
• Hypoplasia of the midface with a parrot-like nose and low-set ears.
• Cleft palate in the form of a high dome and double uvula.
• Syndactyly of hands and feet.
• Anomalies of the heart, lungs and kidneys.
• Acne-like rashes on the skin of the trunk and limbs.
• Mental retardation (in 30% of cases).