What is congenital glaucoma?
Glaucoma is a disorder in which increased pressure develops inside the eyeball. The eye normally produces a clear fluid known as aqueous humor that continuously flows through its chambers delivering nutrients. The aqueous humor drains out of the eye through a special channel called the anterior chamber or iridocorneal angle. If this channel is blocked, the outflow of aqueous humor is impeded, resulting in glaucoma.
By and large, glaucoma is an adult disease. In rare cases, however, it is congenital, which means that it is present at birth or becomes apparent in the first few months of life. This type of glaucoma is also known as infantile glaucoma, buphthalmos, or hydrophthalmos.
Sensitivity to bright light.
- Bulging eyes.
- Cloudy eyeballs.
- Pupils unresponsive to light changes.
- Irritability, possibly due to headaches.
- Teary eyes.
Congenital glaucoma, unlike the acute form of the disease that develops in adults, usually affects both eyes. (The chronic form of adult glaucoma also tends to be bilateral.)
Untreated glaucoma can cause blindness. In infants, the condition often is not detected until some loss of vision has occurred.
What causes congenital glaucoma?
Congenital glaucoma is caused by a defect in the channel through which aqueous humor normally exits the eye. Because of the constant obstruction of the outflow of aqueous humor, a chronic increase in intraocular pressure develops.
Most cases of congenital glaucoma are inherited in an autosomal recessive pattern. Infants with this disorder have received two copies of the same defective gene — one from the mother and one from the father. Those who inherit only one copy of the gene from either parent are carriers of the disease, but they do not develop it themselves.
In some cases, congenital glaucoma occurs in conjunction with another inborn eye abnormality such as aniridia, or absence of the iris. It may also develop as part of an
inherited disorder or syndrome such as neurofibromatosis (a disease in which tan birthmarks and, in some cases, numerous skin tumors develop).
How is congenital glaucoma diagnosed and treated?
Infants cannot communicate any vision problems or other discomfort, such as the blurred vision and headaches reported by adults who develop glaucoma. Therefore, the pediatrician has to rely on objective evaluations and external signs to diagnose congenital glaucoma.
In contrast to glaucoma in adults, in which there are no clearly visible signs of an eye problem, congenital glaucoma is usually associated with observable abnormalities. Infants with congenital glaucoma have abnormally large corneas that may appear cloudy. The pupil — the black center of the eye that normally changes diameter in response to light — is dilated. The iris (the colored portion of the eye) may show signs of atrophy. There may also be excessive tearing and light sensitivity.
In addition, intraocular pressure can be measured with a simple, painless test. Normal intraocular pressure is 20 or lower; infants with congenital glaucoma have readings of 50 to 70.
Treatment usually involves surgery in order to save the infant's vision.
What can I do myself?
No self-treatment can help congenital glaucoma.
When should I see my doctor?
Every infant should be examined by a pediatrician soon after birth and at regular intervals during the first few years of life. Any changes in the size or shape of a baby's eyes, or a failure of the pupils to change in size in response to light, warrants investigation.
What will the doctor do?
Surgery is the only treatment for congenital glaucoma. The surgical approach may involve any of these procedures:
- Goniopuncture, to puncture a hole in the filtration angle of the anterior chamber of the eye.
- Goniotomy, to make an opening in the drainage canal via the angle of the anterior chamber.
- Trabeculotomy, in which a new drainage opening is created.
The course of congenital glaucoma
Congenital glaucoma is usually discovered before the age of 6 months. Although the infant cannot report symptoms, parents can assume that the baby's vision has become increasingly blurry and that headaches, which are often severe, may have developed.
In contrast to acute glaucoma in adults, which is a medical emergency requiring immediate surgery to prevent blindness, congenital glaucoma progresses slowly, in a pattern akin to that of chronic glaucoma in adults. However, unlike adult chronic glaucoma, it cannot be treated with eye drops and it requires surgery.
Surgery can immediately restore normal pressure to the eye and halt further eye damage. However, if the glaucoma has been present for an extended period, the resulting loss of vision cannot be regained.
Is congenital glaucoma dangerous?
Yes. If congenital glaucoma is allowed to progress, the optic nerve becomes damaged and complete blindness may occur.
What can I do to avoid congenital glaucoma?
Since most cases of congenital glaucoma are hereditary, there are no specific preventive steps. Genetic counseling may be advised before a subsequent pregnancy for couples who already have a child with the disease.