Primary congenital glaucoma (PCG) is an eye disease that affects children between the ages of birth and 3 years. It is one type of glaucoma. Glaucoma refers to a group of diseases that affect the eye and cause major damage to the optic nerve.
Primary congenital glaucoma is rare. It affects about one in every 10,000 infants. But it is serious and needs attention. Untreated primary congenital glaucoma is a major cause of childhood blindness.
The signs of a black eye include bruising and swelling of the eyelid and soft tissue around the injured eye, sometimes accompanied by broken blood vessels along the white of the eye, called a subconjunctival hemorrhage.
The discoloration starts out deep purple or blue, then may turn green or yellow before disappearing, usually in about a week.
"Primary" means the disease does not result from another illness or condition, such as a tumor. "Congenital" means it is present at birth.
Although babies are born with primary congenital glaucoma, there may be no sign of it at first. It's commonly found between the ages of 3-6 months. But it can be diagnosed as late as 3 years of age.
If the disease is found and treated early, most children -- 80% to 90% -- respond well. They will not have vision problems in the future.
How Does Primary Congenital Glaucoma Affect the Eye?
This type of glaucoma is generally caused by increased pressure inside the eye. The abnormally high pressure is due to resistance to the flow of the normal circulation of eye fluid (aqueous). This eye fluid is needed to provide proper pressure to the eye. It also delivers nutrients to the interior parts of the eye.
In a healthy eye, the fluid leaves through a network of cells and tissue that functions as a tiny drain. To replace the fluid that drains, the eye continuously makes just the right amount of more fluid.
With glaucoma, something happens to this balance. In most cases, the fluid doesn't drain properly. The buildup of fluid causes the eye pressure to rise.
Increased pressure from the excess fluid damages the fibers that make up the optic nerve. The optic nerve is at the back of the eye. It sends signals to the brain to let you know what you see.
With most kinds of glaucoma, this damage occurs slowly over time. Often, by the time a person notices symptoms, the damage is already extensive. Once vision loss has occurred it is irreversible and cannot be restored.
What Causes Primary Congenital Glaucoma?
The cause of primary congenital glaucoma is not clearly understood. Some cases are inherited. But others are not. The problem of improper drainage of fluid is the result of the lack of full or proper development before birth of the network of cells and tissue that make up the drain.
Who Is Likely to Have Primary Congenital Glaucoma?
It's hard to predict which babies will be born with primary congenital glaucoma. One risk factor is a family history of congenital glaucoma. If the first and second child have the disease, the risk increases significantly for later children.
About twice as many boys as girls are born with primary congenital glaucoma. It sometimes can affect just one eye. But in three out of every four cases both eyes are affected.