Tuesday, 7 January 2014

Pediatric Glaucoma

Glaucoma is a group of diseases characterized by damage to the optic nerve that often occurs when the eye pressure is elevated and can result in severe vision loss. Glaucoma is more common in the elderly but can develop at any age. Infants and children with glaucoma typically have different signs and symptoms than adults.

Types and causes

The subtypes of pediatric glaucoma are based upon the age of onset. Congenital glaucoma is present at birth. Infantile glaucoma develops between the ages of 1-24 months. Glaucoma with onset after age 3 years is juvenile glaucoma.
Most cases of pediatric glaucoma have no specific identifiable cause and are considered primary glaucoma. Secondary glaucoma is typically associated with systemic conditions (Axenfeld-Rieger syndrome, Sturge-Weber syndrome, and neurofibromatosis), medication use (steroids), trauma or previous eye surgery (cataract surgery as a child).
Childhood glaucoma is relatively rare. Primary congenital/ primary infantile glaucoma occurs in approximately 1 in 10,000 births.

Heritance
Some types of pediatric glaucoma are hereditary. About 10% of primary congenital/infantile glaucoma cases are inherited. Recent research has identified specific gene mutations linked to this disease; genetic testing and counseling for affected families may be available soon.
Secondary glaucoma can develop in association with conditions that are inherited in a Mendelian fashion (aniridia is an example).

Symptoms
The most common symptoms of congenital/infantile glaucoma are excessive tearing, light sensitivity and a large, cloudy cornea which can cause the iris to appear dull. Excessive tearing accompanied by mattering/discharge in a child is usually not caused by glaucoma but instead is the result of congenital nasolacrimal duct obstruction.
Enlarged, cloudy corneas in a child with congenital glaucoma

Juvenile glaucoma (Symptoms)
Juvenile glaucoma tends to develop without any obvious symptoms, similar to adult glaucoma.

Evaluation and Diagnosis of Pediatric Glaucoma









When a baby is suspected of having glaucoma, an examination under anesthesia is typically performed [See figure 1]. While under anesthesia the ophthalmologist evaluates the intraocular pressure (for elevation), cornea diameter (for increased size), cornea clarity (for cloudiness and Haab striae which are breaks in the back surface of the cornea), axial length (for elongation of the eye), refractive error (for myopia), and the optic nerve (for abnormal cupping which infers optic nerve damage). Some parts of this examination can be performed in the office on older, cooperative children.













Treatment

Pediatric glaucoma is treated by lowering the intraocular pressure (IOP) via medical and/or surgical means. Most cases of primary pediatric glaucoma are treated with surgery. Trabeculotomy and goniotomy, which open the drainage canal, are the most common surgical interventions. Other procedures create a bypass route for the aqueous out of the eye.
A trabeculectomy creates a guarded opening from the front of the eye to a space underneath the conjunctiva. A tube shunt is a device in which a tube is inserted into the front of the eye or into the vitreous cavity. Fluid from the eye drains to a reservoir that is located on the outside of the eye. Procedures involving laser can also be beneficial in some cases.
Control of the glaucoma often requires multiple procedures and examinations under anesthesia. Eye drops and oral medications are the primary treatments for secondary and juvenile glaucoma and are occasionally used for primary pediatric glaucoma. One to several medications may be necessary to control the IOP, even after surgery.
The treatment of pediatric glaucoma is not simply a matter of lowering IOP. Many children with congenital or infantile glaucoma develop myopia (nearsightedness) and require glasses. Also, amblyopia (lazy eye) and strabismus (crossing or wandering eye) occur more frequently and may require treatment with patching or surgery. Despite timely and aggressive treatment, permanent vision loss can still result from pediatric glaucoma. Early diagnosis and treatment aid in a successful outcome.