Glaucoma is a group of diseases characterized by damage to the optic nerve that often occurs when the eye pressure is too high. This causes optic nerve damage and can result in severe vision loss. Most often the pressure is too high because the eye is able to make the fluid it needs, but is unable to sufficiently drain the fluid out. 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.
One way to classify glaucoma is based on 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. Another way to classify glaucoma is to describe the structural abnormality or systemic condition which has caused the glaucoma.
Most cases of pediatric glaucoma have no specific identifiable cause and are considered primary glaucoma. When glaucoma is caused by, or associated with a specific condition or disease, it is called secondary glaucoma. Examples of conditions which can be associated with childhood glaucoma include Axenfeld-Reiger Syndome, aniridia, Sturge-Weber Syndrome, neurofibromatosis, chronic steroid use, trauma, or previous eye surgery such as childhood cataract removal. Not all patients with these conditions will develop glaucoma, but their incidence of glaucoma is much higher than average and they should be monitored regularly.
Childhood glaucoma is relatively rare. Primary congenital/ primary infantile glaucoma occurs in the general population at a rate of approximately 1 in 10,000 births. However, if a child has cataract surgery or one of the other conditions listed above, the incidence of glaucoma will be much higher. For example, 50% of patients with aniridia will develop glaucoma during their lifetime.
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 is available. In the future, there may be genetic therapies available.
Other secondary glaucoma conditions such as neurofibromatosis and aniridia are dominantly inherited and are passed on to children about 50% of the time.
The most common symptoms of congenital/infantile glaucoma are excessive tearing, light sensitivity and a large, cloudy cornea ( the normally clear front surface of the eye) which can cause the iris (colored part of the eye) 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 (blocked tear duct).
Enlarged, cloudy corneas in a child with congenital glaucoma
Juvenile glaucoma tends to develop without any obvious symptoms, similar to adult glaucoma. Patients with juvenile glaucoma often have a family history. On exam the eye pressure will be elevated and there may be signs of optic nerve cupping (enlargement of the center “cup” portion of the optic nerve).
If 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- caused by stretching from increased pressure), refractive error (for myopia- also caused by stretching), 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. Such children may also be able to participate in a diagnostic visual field exam to evaluate peripheral vision. This will show (when the test results are reliable) if there has been any significant optic nerve damage Additional imaging tests on these children (such as OCT or others) may also sometimes be useful in the evaluation and monitoring for suspected glaucoma.
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 canals, are the most common surgical interventions. Other procedures create a bypass route for the aqueous (fluid made by the eye) to drain out of the eye.
A trabeculectomy creates a guarded opening from the front of the eye to a space underneath the conjunctiva- which is the clear membrane that covers the sclera (the white part of the eye). A tube shunt is a device which is inserted into the front of the eye or into the vitreous cavity (back part of the eye). Fluid from the eye then drains to a reservoir that is located underneath the conjunctiva. Laser procedures 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 often used as adjuvant therapy after surgery in primary pediatric glaucoma. One or more medications may be necessary to control the intraocular pressure (IOP), even after surgery.
The treatment of pediatric glaucoma is not simply a matter of lowering IOP. Many children with pediatric glaucoma develop myopia (nearsightedness) and require glasses. Also, amblyopia (decreased vision) and strabismus (crossing or wandering eye) occur more frequently and may require treatment with patching or surgery. Despite timely and aggressive treatment, pediatric glaucoma can still cause significant and permanent vision loss. Early diagnosis and treatment aid in a successful outcome.
Associated information site: Pediatric Glaucoma and Cataract Family Association (PGCFA)
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