Nelson_Pediatric Ophthalomology, 3e

ANOPHTHALMIA 9

Diagnostic Evaluation ● Anomalous eyelid and orbital features ( Fig. 2-1 ) ● Ultrasound imaging: B-scan ultrasonogra phy of the orbit will show a complete absence of the globe. After 22 weeks’ gestation, trans vaginal ultrasonography can detect eye mal formations, but its sensitivity in the detection of anophthalmia is not known. ● Magnetic resonance imaging (MRI) of the head and orbits: MRI will show the soft tissue within the orbital cavity ( Fig. 2-2 ). Associated intracranial abnormalities can also be evaluated. Individuals with bilateral anophthalmos may have a related hypoplastic or absent optic chiasm as well as agenesis or dysgenesis of the corpus callosum. ● Computed tomography (CT) scan of the head and orbits: CT scan will image the bony changes and intracranial and craniofacial ab normalities seen with anophthalmia. ■ Early socket expansion is important to minimize facial deformities and can be started within weeks of life. Orbital con formers can be placed in the orbital cavity to stimulate growth of the bony orbit ( Fig. 2-3 ). As the orbit grows, the con formers are changed and progressively in creased in size to further expand the orbital cavity. This serial augmentation takes time and cooperation from both the patient and the parents. ■ Contraction and reversal of the benefit often occur if the conformer is left out of the orbit for a significant amount of time. With unilateral anophthalmos, the family should be aware that, most likely, the final result will not mirror the normal healthy orbit. ■ An ocular prosthesis can be fitted over the conformer to simulate the eye and im prove appearance. Treatment ● Medical care

Mutations in SOX2 can disrupt formation of tis sues and organs during embryonic development. RBP4 has also been linked to an autosomal dom inant form of anophthalmia, for which mutations during pregnancy predispose the fetus to vitamin A deficiency. OTX2 , CHX10 , and RAX muta tions can lead to failure of retinal differentiation and may result in anophthalmia. BMP4 has been linked to anophthalmia, microphthalmia, and myopia. Other influential genes known to im pact anophthalmia include CHX10 , RAX , PAX6 , STRA6 , VAX1 , FOXE3 , BMP4 . Symptoms ● Unilateral or bilateral blindness because of the absence of the globe(s) Signs ● The eye is the stimulus for proper growth of the orbital region; therefore, an infant born with anophthalmia has the following: ● Orbital findings ■ Small orbital rim and entrance ■ Reduced size of bony orbital cavity ■ Globe is completely absent. ■ Extraocular muscles are usually absent. ■ Lacrimal gland and ducts may be absent. ■ Small or maldeveloped optic foramen ● Eyelid findings ■ Narrow palpebral fissures ■ Foreshortening of the eyelids ■ Shrunken conjunctival fornices ■ Levator function is decreased or absent with poor eyelid folds. ■ Contracture of the orbicularis oculi muscle Differential Diagnosis ● Microphthalmos ● Cryptophthalmos: abnormal fusion of the en tire eyelid margin with absence of the eyelashes ● Cystic eye: a cyst of neuroglial tissue lack ing normal ocular structures

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