GLAUCOMA
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Congenital Glaucoma

What is Congenital Glaucoma?
The congenital glaucomas are rare, but potentially blinding eye disorders. Although they occur only in about one out of 10,000 infants, their importance is magnified by the young age of the patients. Technically speaking, congenital glaucoma refers to glaucoma which can be either present at birth or appear any time during the first three or four years of life.

In congenital glaucoma, the eye pressure is higher than normal. This is caused by an abnormal drain (trabecular meshwork) in the eye.

When glaucoma is present at birth, the drain is defective and functions poorly, leading to a high pressure. When the glaucoma appears later, for example at the age of one or two years, the defect in the drain is less significant. In general, the younger the age at which the glaucoma appears, the more difficult it may be to treat successfully.

About one-half of babies with congenital glaucoma have what is called primary congenital glaucoma. In this instance, the glaucoma occurs without any other abnormalities in the eye or elsewhere in the body. In the other one-half of babies, there are other abnormalities of the eye or in the rest of the body which are present. These may range from mild to severe. Although congenital glaucoma may be inherited, in most cases it is not. Most babies with congenital glaucoma are born to healthy parents.

How is Congenital Glaucoma Recognized?
Before the age of three, the wall of the eye is very soft and elastic. Therefore, when the eye pressure rises in congenital glaucoma, the eye enlarges. This is often recognized by the parents or pediatrician (Figure 1). After the age of three to four years, the eye is less elastic and does not increase in size when the eye pressure rises.

Although both eyes are most commonly affected, the glaucoma is often more severe in one eye than in the other.

One eye may enlarge more than the other. In some babies, the glaucoma is present only in one eye, particularly when there are other abnormalities. Parents often state that the eye or eyes appear to be becoming more prominent or that one eye is larger than the other.

As the eye enlarges, an inner layer of the cornea, which keeps the cornea transparent, may be torn. As a result, the eye pressure pushes fluid into the cornea, causing it to swell and become hazy. This also is often noticed by the parents as a clouding or whitening of the cornea. When the condition reaches this stage, the eye is painful and tearing is present. The baby becomes sensitive to light and attempts to avoid it by covering the eye or burying the head in a blanket.

There are a number of other conditions which can be confused with congenital glaucoma. The most common of these is tearing due to obstruction of the tear duct, which is outside of the eye. This is not generally a serious condition, and may resolve without treatment. However, corneal clouding and enlargement of the eye indicate a serious situation and the baby should always by examined as soon as possible by an ophthalmologist.

How is Congenital Glaucoma Treated?
Eye surgery is usually necessary, since treatment with eye drops is most often only temporarily helpful in congenital glaucoma. Fortunately, surgical treatment, particularly in glaucoma which develops after the age of six months, is often successful in lowering eye pressure permanently. During the operation, the poorly functioning drain is opened. This exposes the deepest portions of the drain to the aqueous humor (fluid within the eye). Two operations, goniotomy and trabeculotomy, are specifically designed to treat congenital glaucoma. They may have to be performed more than once before the eye pressure is reduced. If these are unsuccessful, then other types of surgery are required.

Fortunately, most babies with congenital glaucoma maintain some degree of vision, and some may even have excellent vision. With expanding knowledge, the next decade may lead to the discovery of the basic causes of congenital glaucoma and a new form of treatment.