Glaucoma

Childhood Glaucoma

Glaucoma refers to a group of eye diseases that have common features, including elevated eye pressure, damage to the optic nerve and vision loss. There are many types of glaucoma. Infantile glaucoma is the term used for glaucoma diagnosed in infancy or early childhood.

Childhood glaucoma is associated with physical changes in the eye which are caused by the high pressure. The increased fluid pressure can push on the optic nerve and cause an abnormal enlargement in the central optic disc area. If the pressure remains too high for too long the optic nerve fivers are damaged. Enlargement of the eye, cloudiness of the cornea and injury to the optic nerve are examples of changes that can occur as a result of glaucoma.

Normal Anatomy

The sclera is the white of the eye covered by a thin membrane called the conjunctiva. The front of the eye consists of the cornea, which is the clear part of the eye continuous with the sclera that allows light to enter. The iris is the colored part of the eye, at the center of which is the pupil (it appears black) that can shrink and expand depending on the amount of light present. Behind the iris and pupil is the lens which focuses the light onto the retina, lining the back wall of the eye.

The front of the eye is filled with a watery fluid called the aqueous humor. The fluid is in a constant state of simultaneous production and absorption. The fluid is absorbed by the trabecular meshwork.

The pressure of the fluid inside the eye (the intraocular pressure or IOP) depends on this rate of production and absorption.

Causes of glaucoma

There are many possible causes for the drainage problem that results in childhood glaucoma. In each case, abnormal fluid drainage from the eye is the result of a blocked or defective trabecular meshwork drainage system. The defect may be primary, or not associated with other eye defects. Primary glaucoma may be due to a hereditary defect or caused by a non-hereditary event during development. In other cases an abnormal drainage system may be a result of some other disease activity in the eye which results in secondary glaucoma. In these cases, the glaucoma may be associated with recognizable iris, corneal, or other problems

Signs and Symptoms

Many cases begin with little or no symptoms. There is usually a gradual onset of problems that include light sensitivity (photophobia), opacification of the normally clear cornea, overflow of tears (epiphora) and vision loss. In addition, the eye can begin to enlarge from the increased pressure; this may be noticed in photographs. Other signs can include irritability, loss of appetite and vomiting. There is probably no pain.

Diagnosis

The diagnosis of glaucoma is made after careful examination by an ophthalmologist. This may include a lengthy office visit. If the child is too young, this examination may have to be carried out in the operating room with the aid of general anesthesia. The parent will likely be asked to help comfort, encourage and sometimes help restrain their child. These exams may need to be repeated on a frequent basis.

Treatment

Medical treatment involves the use of medicines. They can be in the form of eye drops or oral preparations. These medicines either decrease the production of fluid inside the eye or help to increase its exit from the eyes.

Surgical treatment is almost always required in childhood glaucoma. Microsurgical techniques are used to open the drainage channel in the eye. Depending on the clarity of the cornea this will be accomplished by an incision in the white of the eye (trabeculotomy) or by a direct incision into the canal via the cornea (goniotomy). If these techniques fail, they can be repeated, or other surgical treatments including lasers and implantable drainage valves can be used. Multiple surgeries are not uncommon. The success rate of these surgeries varies on the age of the patient and the severity of the disease. A definite treatment plan and prognosis varies in each individual case and is not the same for every patient.

Note
Much of the information above was obtained from a publication entitled, “Childhood Glaucoma, A Reference Guide for Families,” published by the Glaucoma Research Foundation. For a copy of this brochure please contact:

Glaucoma Research Foundation
200 Pine Street, Suite 200
San Francisco, CA 94104
800-826-6693
www.glaucoma.org