Daniel T. Weaver
Alex V. Levin

BASICS

DESCRIPTION

• Trabeculodysgenesis with aqueous outflow obstruction resulting in increased intraocular pressure detected at birth or by age 3–4 years

• Differentiated from secondary forms of childhood glaucoma that may be associated with: Persistent fetal vasculature, Peters anomaly, Axenfeld-Rieger spectrum, aniridia, retinopathy of prematurity, Marfan syndrome, and microspherophakia.

• Differentiated from acquired forms of pediatric glaucoma, such as aphakic or pseudophakic glaucoma, infectious, uveitic, or trauma-related glaucoma.

• Unilateral (25%) or bilateral (75%)

EPIDEMIOLOGY

Incidence

• Variable depending on country

• In some Middle Eastern countries: 1 per 4 to 10,000

• In the US, 0.38 per 100,000 (1)[C]

Prevalence

• In the US, 1.46 per 100,000 (1)[C]

RISK FACTORS

• 3:2 Males:Females

• Family history

Genetics

• 10% are autosomal recessive with variable penetrance and expressivity; autosomal dominant forms are less common.

• Four loci have been identified (2)[C]:

– GLC3A (2p21), due to mutations in the cytochrome P450, family 1, subfamily B, polypeptide 1 (CYP1B1) gene

– GLC3B (1p36), gene not yet identified

– GLC3C (14q24.3), gene not yet identified

– GLC3D, due to mutations in the latent transforming growth factor binding protein 2 (LTBP2) gene

– Digenic with mutations in CYP1B1 and FKHL7/FOXC1/forkhead transcription factor

• Mutations in the myocillin (MYOC) gene have been identified in some cases of infantile glaucoma (autosomal dominant)

• Other loci are thought to exist but have not yet been characterized (2)[C]

GENERAL PREVENTION

• No known modes of prevention, other than genetic counseling. Prenatal testing only available if mutation known.

PATHOPHYSIOLOGY

• There are several theories of pathogenesis:

– Barkan’s membrane covering the trabecular meshwork (may not be true)

– Anterior insertion of the ciliary body (due to arrest in the normal migration of the uvea) may contribute to narrowing or collapse of Schlemm’s canal

– Absent Schlemm’s canal

– Anomalous trabecular meshwork development (neural crestopathy)

ETIOLOGY

• May result from genetic or teratogenic interference with neural crest cell formation, migration, and final differentiation during fetal development.

COMMONLY ASSOCIATED CONDITIONS

• Congenital glaucoma may be associated with many systemic syndromes including Sturge-Weber syndrome, Lowe syndrome, congenital rubella, Kniest skeletal dysplasia, Robinow syndrome, and others as well as with chromosomal abnormalities.

DIAGNOSIS

HISTORY

• Classic triad:

– Epiphora

– Photophobia

– Blepharospasm

• Large or asymmetric eyes

• Iris heterochromia may be present

• Cloudy cornea(s)

• Rapid myopic shift

PHYSICAL EXAM

• Exam under anesthesia or sedation may be needed to detect the following signs:

– Long axial length by A-scan

– Large corneal diameter (>12 mm for full term infants)

– Hand held slit-lamp examination may reveal cloudy corneas or Haab’s striae (breaks in Descemet’s membrane, usually horizontal)

– Cycloplegic streak retinoscopy may be useful in detecting progressive myopia or rapid loss of hyperopia

– Tonometry should be obtained at anesthesia induction with the Tonopen or Perkins tonometer. Normal infant IOP is 10–15 mm Hg; IOP in congenital glaucoma typically 25–35 mm Hg

– Gonioscopy may reveal an anterior iris insertion and indistinct trabecular meshwork.

– Ophthalmoscopy will reveal optic nerve cupping, which is usually concentric with healthy surrounding disc tissue until late stages (sloping, notching, and hemorrhage are uncommon). May be reversible.

• In the office, assess the following:

– Visual acuity

– Pupils (assess for afferent pupillary defect)

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