Diseases of the anterior chamber

Glaucoma

If there is obstruction to the flow of aqueous humour the pressure in the anterior chamber will rise. This is called glaucoma, which can damage the optic nerve and subsequently affect visual fields and later vision if not effectively treated.

Although glaucoma in children is uncommon, it accounts for 2 - 15% of blindness in childhood.

Glaucoma may be primary in which there is a developmental abnormality of the drainage angle of the anterior chamber or secondary, due to a variety of other causes.

The commonest form of primary glaucoma is primary congenital glaucoma in which the drainage angle of the anterior chamber does not develop normally. It is usually bilateral but may be unilateral. Children usually present with classic symptoms of glaucoma, which include watering, sensitivity to light, an obviously enlarged eye (buphthalmos), one eye larger than the other and corneal swelling and clouding but in milder cases people may comment on beautiful and large eyes of the child. All children will require surgery to open up the drainage angle. This is an ophthalmic emergency.

The other primary glaucoma is juvenile onset open angle glaucoma in which children present after the age of 3. These children tend to respond well to surgery to drain the anterior chamber.

There are numerous causes of secondary glaucoma that include developmental disorders of the eye, trauma, eye surgery, Neurofibromatosis (a genetic disease causing multiple soft tumours under the skin), Sturge Weber Syndrome (a congenital disease marked by a port-wine-coloured stain over the trigeminal nerve of the face), metabolic disorders, infections, inflammatory conditions, ocular tumours, chromosomal disorders and connective tissue disorders. Secondary glaucoma may also occur in children with congenital cataracts.

Glaucoma is diagnosed using a tonometer which tests the pressure in the eye. Tonometry may be performed whilst awake in babies but usually has to be carried out under anaesthetic in children up to about the age of 5 years of age.

The primary treatment of childhood glaucomas is surgery. However, medical treatment in the form of eye drops may be helpful to control intraocular pressure while waiting for surgery and may be required in the long term after surgery. Cyclodiode laser therapy and insertion of drainage devices are other methods of treatment.

Children need lifelong follow up because they can relapse for several decades after the initial treatment.

Amblyopia (a lazy eye) is a significant complication of childhood glaucoma and is important as a cause of poor vision in these children. Myopia or shortsightedness, squint and nystagmus (jerky eye movements) may be consequences of glaucoma.

Prognosis: The outlook is variable with the majority of children having moderate to severe visual impairment.