Glaucoma
Glaucoma-The Basics
What is glaucoma?
Glaucoma is a disease of the optic nerve, which is the part of the eye that carries the images we see from the eye to the brain.
The optic nerve is made up of many nerve fibers (like an electric cable containing numerous wires). Glaucoma damages nerve
fibers, which can cause blind spots in our vision and vision loss to develop.
Glaucoma has to do with the pressure inside the eye, or intraocular pressure (IOP). When the clear liquid called the
aqueous humor--which normally flows in and out of the eye--cannot drain properly, pressure builds up in the eye. The
resulting increase in IOP can damage the optic nerve.
The most common form of glaucoma is primary open-angle glaucoma, where the aqueous fluid that normally circulates in
the front portion of the eye is blocked from flowing back out of the eye through a tiny drainage system. This causes
the pressure inside your eye to increase, which can damage the optic nerve and lead to vision loss. Most people who
develop primary open-angle glaucoma notice no symptoms until their vision is impaired.
In angle-closure glaucoma, the iris (the colored part of the eye) may drop over and completely close off the drainage
angle, abruptly blocking the flow of aqueous fluid and leading to increased IOP or optic nerve damage. In acute
angle-closure glaucoma there is a sudden increase in IOP due to the buildup of aqueous fluid. This condition is
considered an emergency because optic nerve damage and vision loss can occur within hours of the problem. Symptoms
can include nausea, vomiting, seeing haloes around light, and eye pain.
Even people with "normal" IOP can experience vision loss from glaucoma. This condition is called normal tension
glaucoma. In this type of glaucoma, the optic nerve is damaged even though the IOP is considered normal. Normal
tension glaucoma is not well understood, but we do know that lowering IOP has been shown to slow progression of
this form of glaucoma.
Childhood glaucoma is rare, and starts in infancy, childhood or adolescence. Like primary open-angle glaucoma,
there are few, if any, symptoms in the early stage. Blindness can result if it is left untreated. Like most types
of glaucoma, this type of glaucoma may run in families.
Your ophthalmologist may tell you that you are at risk for glaucoma if you have one or more risk factors,
including elevated IOP, a family history of glaucoma, a particular ethnic background, advanced age, or certain
optic nerve conditions. Regular examinations with your ophthalmologist are important if you are at risk for this condition.
Glaucoma: People of African Descent are at Risk
If you are of African ancestry, especially if you have a known family member with glaucoma, you are at risk
for vision loss from this eye disease.
Glaucoma is a disease of the optic nerve, which is the part of the eye that carries the images we see
from the back of the eye to the brain. The optic nerve is made up of many nerve fibers (like an electric
cable containing numerous wires). Glaucoma damages nerve fibers, causing blind spots and loss of vision
to develop.
Glaucoma has to do with the pressure inside your eye, or intraocular pressure (IOP). When the clear liquid
called the aqueous humor--which normally flows in and out of the eye--cannot drain properly, pressure builds
up in your eye. The resulting increase in IOP can damage the optic nerve.
Primary open angle glaucoma is the leading cause of blindness among people of African descent, occurring at a
rate four times higher than among Caucasian patients. It also occurs about ten years earlier among people of
African ancestry than among Caucasians, and develops more rapidly. Studies show that in the United States,
people of African descent between the ages of 45-64 are approximately 15 times more likely to go blind from
glaucoma than Caucasians with glaucoma in the same age group.
It is not clear why people of African ancestry have higher rates of glaucoma and subsequent blindness than
Caucasians. One factor may be that African-Americans are more susceptible to developing elevated eye pressure
(IOP) earlier in life, which is thought to contribute to optic nerve damage and eventual vision loss. Another
reason may be that patients of African descent are less likely than Caucasians to have early eye examinations
that may detect and treat glaucoma.
The best way to protect yourself and your family members against vision loss from glaucoma is by being aware
of the higher risk of developing this disease, and by having regular eye examinations for glaucoma at appropriate
intervals.
If you are at risk for developing glaucoma, you can help to protect yourself fro vision loss by having regular
eye examinations for glaucoma at appropriate intervals. Recommended intervals for a comprehensive eye evaluation
in people of African descent are:
- Age 20-29: every 3-5 years
- Age 30-64: every 2-4 years
- Age 65+: every 1 to 2 years
If you are diagnosed with glaucoma, please make sure you tell your family members and urge them to
have an eye exam for glaucoma. For more information on glaucoma:
The Glaucoma Foundation
116 John Street, Suite 1605
New York, NY 10038
Phone: 1-800-GLAUCOMA (1-800-452-8266)
www.glaucoma-foundation.org
The National Eye Institute
2020 Vision Place
Bethesda, MD 20892-3655
Phone: (301) 496-5248
www.nei.nih.gov
Prevent Blindness America
1-800-331-2020
www.preventblindness.org
The American Academy of Ophthalmology
P.O. Box 7424
San Francisco, CA 94120-7424
www.aao.org
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