Glaucoma
Glaucoma is the
leading cause of blindness in the United States. It is a disease
that typically affects older people, but it can occur at any
age. Loss of vision is preventable if the disease is detected
early and treatment is started.
The eye has about 1 million tiny nerve fibers which run from
the back of the eye to the brain. These nerve fibers allow us
to see. Glaucoma is a disease which causes the destruction of
these fibers. It was once thought that the loss of these fibers
was due to strictly to high pressure in the eye. But now it is
known that even patients with normal eye pressure can have glaucoma
and loss of these nerve fibers.
In many patients, the disease is not noticed in the early stages,
because there is no pain and no noticeable change in vision.
Early detection by an eye doctor is the key to the prevention
of vision damage from glaucoma. Routine eye examinations are
recommended.
Types of Glaucoma
The reason that eye pressure is high in many glaucoma patients
is that the drainage system in the eye is not working properly.
The fluid in the eye, called aqueous humor, does not flow out
of the eye as quickly as it should. The drainage system lies
in a part of the eye called the angle, which is between the outer
layer and the iris of the eye. This angle can be open or closed.
There are several kinds of glaucoma. The most common form of
glaucoma is called chronic open angle glaucoma. The drainage
angle is open in these patients, but the eye fluid does not drain
as quickly as it should. Closed-angle glaucoma occurs when the
drainage angle closes, and almost no eye fluid can escape. During
closed-angle glaucoma, eye pressure can get very high and there
is pain. Angle closure glaucoma is an emergency and must be treated
immediately. If the high pressure is allowed to continue for
too long, blindness can result.
Some persons are more likely to have glaucoma. These include
persons who are older, have nearsightedness, have a family history
of glaucoma, have had past eye injury, have diabetes or have
a past history of vascular shock. Also, African-Americans are
6 times more likely to have the disease.
Glaucoma is treated with eye drops that lower the eye pressure.
If the pressure does not fall to a low enough level with drops,
then surgery may be necessary. Glaucoma surgery opens up the
drainage system in the angle so that the eye fluid can flow more
freely.