Childhood glaucoma

Introduction

Glaucoma in children is a rare, potentially blinding condition. Characterized by elevated intraocular pressure-related damage to the eye, it is caused by a diverse group of conditions. Clinical presentation can vary; unlike glaucoma in the adult and depending on the age of onset, elevated intraocular pressure (IOP) can affect the whole eye and not just the optic nerve. The management of pediatric glaucoma is challenging and is very often surgical in nature. The aim is to provide a lifetime of vision by successfully controlling the child’s intraocular pressure for the duration of their life expectancy. Glaucoma filtration surgery is associated with a higher complication rate and a higher failure rate, due to the vigorous healing response in children as compared to adults. However, if the correct procedure is chosen and performed with meticulous care, complications can be minimized and success rates optimized. As most children will need several surgeries over the course of their life, consideration needs to be taken of the impact on their families and carers, as well as their schooling. The correction of ametropia and amblyopia therapy is also vital to maximize visual function.

Clinical presentation

A child suspected of having glaucoma can present in many ways. They may present with:

• 1.

  The clinical manifestations of elevated IOP, as occurs in infancy.

• 2.

  A condition that predisposes them to glaucoma, e.g. aphakia.

• 3.

  During screening when there is a family history of childhood glaucoma.

• 4.

  After having failed routine school vision testing.

Glaucoma from any cause in a neonate or infant is synonymous with the classic triad of lacrimation, blepharospasm, and photophobia due to corneal edema from elevated IOP. These signs are very suggestive of glaucoma and may appear before the hazy cornea and characteristic buphthalmos become obvious. Buphthalmos (ox eye), refers to the generalized ocular enlargement caused by elevated IOP from any cause in infancy ( Fig. 36.1 ). It is a unique finding of glaucoma in infancy because the young eye expands with increased IOP due to corneal and scleral collagen immaturity. The potential for corneal enlargement usually ceases by the age of 3 years, although the sclera remains deformable until around 10 years of age. As the IOP rises, Descemet’s membrane can rupture and retract as a scroll to form a ridge known as a Haab stria ( Fig. 36.2 ). The underlying endothelium tears, resulting in localized or diffuse corneal edema from aqueous influx into the stroma, causing a sudden cloudiness ( Fig. 36.3 ). With successful lowering of IOP, corneal clouding typically begins clearing first in the periphery ( Figs. 36.4 and 36.5 ). As the IOP returns to normal, photophobia may still persist due to the Haab striae. Over the age of 3 years, children are more likely to present with progressive myopia, strabismus, or after having failed vision testing.

Differential diagnosis

The differential diagnosis of glaucoma in children is broad ( Box 36.1 ). Many conditions mimic glaucoma, which must be excluded before making this diagnosis. In patients with other diagnoses, the IOP is normal and the signs will usually not be progressive.

Classification

Childhood glaucoma can simply be classified as: primary, where there is an isolated developmental abnormality of the anterior chamber (AC) angle; and secondary, where aqueous outflow is reduced by non-acquired (congenital) or acquired ocular diseases or systemic disorders ( Box 36.2 ).