Glaucoma—Congenital

Basics

Description

  • Elevation of intraocular pressure (IOP) due to congenital anomalies that prevent outflow of aqueous humor, leading to damage to the optic nerve
  • Neonatal primary congenital glaucoma (PCG), presents at birth
  • Depending on the degree of the malformation, presentation can occur even later in life.
  • About 80% of childhood glaucoma presents in the 1st year of life. Secondary congenital glaucoma is associated with systemic conditions.

Epidemiology

  • PCG accounts for ~1/2 of all cases of childhood glaucoma.
  • 1:10,000 births (ranging from 1:2,500 in Saudi Arabia to 1:38,000 in Spain)
  • Male > female (3:2)
  • ~70% bilaterally affected

Pathophysiology

  • PCG is caused by immature anatomic relationship between the iris, trabecular meshwork, and cornea.
  • Secondary glaucoma is mostly due to damage or alteration of the trabecular meshwork.

Genetics

  • Most are sporadic, but 10–40% are familial.
  • Autosomal recessive is most common.
  • PCG is associated with mutations in cytogenic locations 2p22.2 (GLC3A), 1p36.2-p36.1 (GLC3B), 14q24.3 (GLC3C), and 14q24.2-q24.3 (GLC3D).

Etiology

  • Aqueous humor, a clear fluid produced by the ciliary body at the posterior base of the iris, passes through the pupil and exits through the trabecular meshwork and Schlemm canal, which are located at the junction of the cornea and iris.
  • Outflow blockage of aqueous humor causes pressure to build in eye.
  • The blockage may be microscopic (open-angle glaucoma) or due to obstruction of the outflow by the iris (angle-closure glaucoma).
  • High IOP in young children leads to enlargement of eye and destruction of fibers of the optic nerve.

Commonly Associated Conditions

  • Sturge-Weber syndrome
  • Neurofibromatosis type 1
  • Oculocerebrorenal (Lowe) syndrome
  • Marfan syndrome
  • Rubinstein-Taybi syndrome
  • Stickler syndrome
  • Walker-Warburg syndrome
  • Hepatocerebrorenal syndrome (Zellweger)
  • Pierre Robin syndrome
  • Homocystinuria
  • Rubella
  • Trisomy 13
  • Trisomy 21 (Down syndrome)
  • Axenfeld-Rieger syndrome
  • Ocular Anomalies
    • Aniridia
    • Peters anomaly
    • Sclerocornea
    • Congenital iris ectropion syndrome
    • Congenital cataract
ALERT
Intraocular neoplasms such as retinoblastoma can cause glaucoma. Other causes of secondary glaucoma include trauma and chronic uveitis.

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