Congenital Glaucoma

Affected infants may be born with a high intraocular pressure or may develop an increased IOP within the first weeks of life.

The Cause

Congenital glaucoma is a rare form of glaucoma. Both eyes are usually involved, but to varying; boys are affected slightly more frequently than girls. A hereditary factor is occasionally present. The genes responsible for the development of the eye and the mutations inducing glaucoma and other genetic defects are currently being researched, and there has already been some progress made in their identification. However, there are also sporadic cases, meaning found among children who have no known hereditary tendency for developing congenital glaucoma.

The IOP elevation is caused by the failure of the anterior chamber angle and the trabecular meshwork to develop appropriately during intrauterine development. In these infants, the aqueous humor does not properly drain, but since the production of aqueous humor is nevertheless normal, the intraocular pressure is high.

Figure 3.1 shows a regularly developed chamber angle, whereas in Fig. 3.2, the trabecular meshwork has not yet fully developed and is still partially covered by a membrane.

Consequences of an Increased IOP during Infancy

Depending on the IOP level, glaucomatous damage is inevitable after weeks, months or even years. This basically occurs via the same mechanisms as in the adult. In addition to optic nerve damage, the globe (eyeball) enlarges because the sclera in the eye of a baby is distensible. 

All segments of the outer eye, but especially the cornea and sclera, expand. The eyes of these afflicted children are thus large (Fig. 3.3).

However, certain layers of the cornea are not very elastic, and stretching may result in small tears that cause a certain degree of corneal opacification (Fig. 3.4)

Fig. 3.4:  Opacified cornea in an afflicated with congenital glaucoma.

If the IOP is lowered, this opacity is partially reversible. As a result of the optic nerve damage and/or corneal opacity, children with congenital glaucoma may be permanently visually impaired.

As mentioned earlier, the eyes, optic nerves and certain segments of the brain participate in the visual process. At the time of birth, this visual system is not yet fully developed. During the first years of life, this system can complete its development only if there is normal binocular vision. If one eye does not see properly during childhood (for example, because of a unilateral lens opacification), maturation of the visual apparatus on this side is threatened. Without appropriate therapy, it is likely that vision will be permanently impaired because full development has never been achieved (i.e. amblyopia) [Gr. amblys: blunt; Gr. opsein: to see]. Amblyopia can only be treated during childhood, correction as an adult is not possible. It is therefore of utmost importance that young glaucoma patients be able to use both eyes and that they have normal binocular vision as soon as possible.

Diagnosis of Congenital Glaucoma

Fortunately, congenital glaucoma is not a common disease: only about one in ten thousand newborns is affected. Early detection of this ailment is essential; these children can be helped if diagnosed in time.

What are the specific signs and symptoms that lead one to suspect congenital glaucoma?

First of all, enlarged eyes; tear flow is often increased and photophobia (avoidance of light) causes these babies to squeeze their eyes shut). Often, they also rub their eyes.

How is Congenital Glaucoma Diagnosed?

Examining newborns and infants is a bit more difficult than checking an adult’s eye. If glaucoma is suspected, a thorough examination under general anesthesia is necessary. This is the only way to measure the IOP without putting too much stress on the baby and to avoid blepharospasm (spasmodic closure of the eyes). Blepharospasm can, in turn, lead to a transient rise in the IOP. Besides measuring the IOP, anesthesia allows a thorough investigation of all segments of the eye and, in particular, the optic disc.

Treatment of Congenital Glaucoma

Treatment depends on the severity of the disease. In moderate cases, one might start with IOP-lowering eye drops. But usually, especially in advanced disease stages, surgery is required to reduce the intraocular pressure. The ophthalmic surgeon will decide when and which type of procedure is necessary.

Fig. 3.5:  Trabeculotomy in congenital glaucoma.                       Fig. 3.6 :  Goniotomy in congenital glaucoma.

Several surgical procedures are possible. Figure 3.5 shows a trabeculotomy, and Fig. 3.6, a goniotomy. Another option is a trabeculectomy, described under procedures for adult glaucoma patients. The purpose of all these techniques is to improve the aqueous humor outflow and thus lower the IOP to normal levels.

Because the intraocular pressure can again increase at any time, even after a successful operation, frequent follow-up examinations by the ophthalmologist are necessary. Should the IOP again increase, medication must be started or the operation repeated. It is not only possible to do surgery again and again, it is sometimes inevitable. Congenital glaucoma can be associated with additional birth defects of the eye or other parts of the body. When certain signs occur together, they often make up a ”syndrome” (for example, Axenfeld-Rieger Syndrome, Peters’ anomaly, aniridia, neurofibromatosis, etc.). In particular, this means that every child born with congenital glaucoma has to be examined for other diseases or birth defects. Likewise, a child having any of these birth defects must have his IOP examined as early as possible so glaucoma can be identified or excluded.