Glaucoma
Information
for Patients
This pamphlet is designed
to help people with glaucoma and their families better understand the
disease. It describes the causes, symptoms, diagnosis, and treatment
of glaucoma. It is mainly about open-angle glaucoma, the most common
kind in the United States.
Glaucoma is a group
of diseases that can lead to damage to the eye's optic nerve and result
in blindness.
Open-angle glaucoma,
the most common form of glaucoma, affects about 3 million Americans—half
of whom don't know they have it. It has no symptoms at first. But over
the years it can steal your sight. With early treatment, you can often
protect your eyes against serious vision loss and blindness.
1.
What is the optic nerve?
2. How does glaucoma damage the optic nerve?
3. Who is at risk?
4. What are the symptoms of glaucoma?
5. How is glaucoma detected?
6. Can glaucoma be treated?
7. What are some other forms of
glaucoma?
8. What research is being done?
9. What can you do to protect your
vision?
1. What is the optic nerve?
The optic nerve
is a bundle of more than 1 million nerve fibers. It connects the retina,
the light-sensitive layer of tissue at the back of the eye, with the
brain (see diagram). A healthy optic nerve is necessary for good vision.
2. How does glaucoma damage the
optic nerve?
In many people,
increased pressure inside the eye causes glaucoma. In the front of the
eye is a space called the anterior chamber. A clear fluid flows
continuously in and out of this space and nourishes nearby tissues.
 The
fluid leaves the anterior chamber at the angle where the cornea
and iris meet (see diagram). When the fluid reaches the angle,
it flows through a spongy meshwork, like a drain, and leaves the eye.
Open-angle glaucoma
gets its name because the angle that allows fluid to drain out of the
anterior chamber is open. However, for unknown reasons, the fluid
passes too slowly through the meshwork drain. As the fluid builds up,
the pressure inside the eye rises. Unless the pressure at the front
of the eye is controlled, it can damage the optic nerve and cause vision
loss.
3. Who
is at risk?
Although anyone
can get glaucoma, some people are at higher risk than others. They include:
- Blacks over age
40.
- Everyone over
age 60.
- People with a
family history of glaucoma.
4. What
are the symptoms of glaucoma?
At first, open-angle
glaucoma has no symptoms. Vision stays normal, and there is no pain.
As glaucoma remains untreated, people may notice that although they
see things clearly in front of them, they miss objects to the side and
out of the corner of their eye.
Without treatment,
people with glaucoma may find that they suddenly have no side vision.
It may seem as though they are looking through a tunnel. Over time,
the remaining forward vision may decrease until there is no vision left.
5. How
is glaucoma detected?
Most people think
that they have glaucoma if the pressure in their eye is increased. This
is not always true. High pressure puts you at risk for glaucoma. It
may not mean that you have the disease.
Whether or not you
get glaucoma depends on the level of pressure that your optic nerve
can tolerate without being damaged. This level is different for each
person.
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| View of boys by person with normal vision. |
View of boys by person with glaucoma. |
Although normal
pressure is usually between 12ń21 mm Hg, a person might have glaucoma
even if the pressure is in this range. That is why an eye examination
is very important.
To detect glaucoma,
your eye care professional will do the following tests:
- Visual
acuity: This eye chart test measures how
well you see at various distances.
- Visual Field:
This test measures your side (peripheral) vision. It helps your eye
care professional find out if you have lost side vision, a sign of
glaucoma.
- Pupil dilation:
This examination provides your eye care professional with a better
view of the optic nerve to check for signs of damage. To do this,
your eye care professional places drops into the eye to dilate (widen)
the pupil. After the examination, your close-up vision may remain
blurred for several hours.
- Tonometry:
This standard test determines the fluid pressure inside the eye. There
are many types of tonometry. One type uses a purple light to measure
pressure. Another type is the "air puff," test, which measures the
resistance of the eye to a puff of air.
6. Can glaucoma be treated?
Yes. Although you
will never be cured of glaucoma, treatment often can control it. This
makes early diagnosis and treatment important to protect your sight.
Most doctors use medications for newly diagnosed glaucoma; however,
new research findings show that laser surgery is a safe and effective
alternative.
Glaucoma treatments
include:
Medicine:
Medicines are the most common early treatment for glaucoma. They come
in the form of eyedrops and pills. Some cause the eye to make less fluid.
Others lower pressure by helping fluid drain from the eye.
Glaucoma drugs may
be taken several times a day. Most people have no problems. However,
some medicines can cause headaches or have side effects which affect
other parts of the body. Drops may cause stinging, burning, and redness
in the eye. Ask your eye care professional to show you how to put the
drops into your eye. In addition, tell your eye care professional about
other medications you may be taking before you begin glaucoma treatment.
Many drugs are available
to treat glaucoma. If you have problems with one medication, tell your
eye care professional. Treatment using a different dosage or a new drug
may be possible.
You will need to
use the drops and/or pills as long as they help to control your eye
pressure. This is very important. Because glaucoma often has
no symptoms, people may be tempted to stop or may forget to take their
medicine.
Laser surgery
(also called laser trabeculoplasty): Laser surgery helps fluid drain
out of the eye. Although your eye care professional may suggest laser
surgery at any time, it is often done after trying treatment with medicines.
In many cases, you will need to keep taking glaucoma drugs even after
laser surgery.
Laser surgery is
performed in an eye care professional's office or eye clinic. Before
the surgery, your eye care professional will apply drops to numb the
eye.
As you sit facing
the laser machine, your eye care professional will hold a special lens
to your eye. A high-energy beam of light is aimed at the lens and reflected
onto the meshwork inside your eye. You may see flashes of bright green
or red light. The laser makes 50-100 evenly spaced burns. These burns
stretch the drainage holes in the meshwork. This helps to open the holes
and lets fluid drain better through them.
Your eye care professional
will check your eye pressure shortly afterward. He or she may also give
you some drops to take home for any soreness or swelling inside the
eye. You will need to make several followup visits to have your pressure
monitored.
Once you have had
laser surgery over the entire meshwork, further laser treatment may
not help. Studies show that laser surgery is very good at getting the
pressure down. But its effects sometimes wear off over time. Two years
after laser surgery, the pressure increases again in more than half
of all patients.
Conventional
surgery: The purpose of surgery is to make a new opening for the
fluid to leave the eye. Although your eye care professional may suggest
it at any time, this surgery is often done after medicine and laser
surgery have failed to control your pressure.
Surgery is performed
in a clinic or hospital. Before the surgery, your eye care professional
gives you medicine to help you relax and then small injections around
the eye to make it numb.
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The
eye care professional removes a small piece of tissue from the white
(sclera) of the eye. This creates a new channel for fluid to drain
from the eye. But surgery does not leave an open hole in the eye.
The white of the eye is covered by a thin, clear tissue called the
conjunctiva. The fluid flows through the new opening, under the
conjunctiva, and drains from the eye.
You must
put drops in the eye for several weeks after the operation to
fight infection and swelling. (The drops will be different than
the eyedrops you were using before surgery.) You will also need
to make frequent visits to your eye care professional. This is
very important, especially in the first few weeks after surgery.
In some patients,
surgery is about 80 to 90 percent effective at lowering pressure.
However, if the new drainage opening closes, a second operation
may be needed. Conventional surgery works best if you have not
had previous eye surgery, such as a cataract operation.
Keep in mind
that while glaucoma surgery may save remaining vision, it does
not improve sight. In fact, your vision may not be as good as
it was before surgery.
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Like
any operation, glaucoma surgery can cause side effects. These include
cataract, problems with the cornea, inflammation or infection inside
the eye, and swelling of blood vessels behind the eye. However, if you
do have any of these problems, effective treatments are available.
7. What are some other forms of glaucoma?
Although open-angle
glaucoma is the most common form, some people have other forms of the
disease.
- In low-tension
or normal-tension glaucoma, optic nerve damage and narrowed side
vision occur unexpectedly in people with normal eye pressure. People
with this form of the disease have the same types of treatment as
open-angle glaucoma.
- In closed-angle
glaucoma, the fluid at the front of the eye cannot reach the angle
and leave the eye because the angle gets blocked by part of the iris.
People with this type of glaucoma have a sudden increase in pressure.
Symptoms include severe pain and nausea as well as redness of the
eye and blurred vision. This is a medical emergency. The patient
needs immediate treatment to improve the flow of fluid. Without treatment,
the eye can become blind in as little as one or two days. Usually,
prompt laser surgery can clear the blockage and protect sight.
- In congenital
glaucoma, children are born with defects in the angle of the eye
that slow the normal drainage of fluid. Children with this problem
usually have obvious symptoms such as cloudy eyes, sensitivity to
light, and excessive tearing. Surgery is usually the suggested treatment,
because medicines may have unknown effects in infants and be difficult
to give to them. The surgery is safe and effective. If surgery is
done promptly, these children usually have an excellent chance of
having good vision.
- Secondary
glaucomas can develop as a complication of other medical conditions.
They are sometimes associated with eye surgery or advanced cataracts,
eye injuries, certain eye tumors, or uveitis (eye inflammation). One
type, known as pigmentary glaucoma, occurs when pigment from the iris
flakes off and blocks the meshwork, slowing fluid drainage. A severe
form, called neovascular glaucoma, is linked to diabetes. Also, corticosteroid
drugs—used to treat eye inflammations and other diseases—can trigger
glaucoma in a few people. Treatment is with medicines, laser surgery,
or conventional surgery.
8. What research is being done?
The National Eye
Institute (NEI) is the Federal government's lead agency for vision research.
The NEI is supporting many research studies both in the laboratory and
with patients. This research should provide better ways in the future
to detect, treat, and prevent vision loss in people with glaucoma.
For instance, researchers
recently found a gene that causes a form of glaucoma that starts at
a young age. This is the first glaucoma gene ever located. This finding
could help us learn more about how glaucoma damages the eye.
The NEI is also
supporting clinical studies that will tell us more about who is likely
to get glaucoma, when to treat people with increased pressure, and which
treatment to use first.
9. What can you do to protect
your vision?
If you are being
treated for glaucoma, be sure to take your glaucoma medicine every day
and see your eye care professional regularly.
You can also help
protect the vision of family members and friends who may be at high
risk for glaucoma—Blacks over age 40 and everyone over age 60. Encourage
them to have an eye examination through dilated pupils every two years.
For more information
about glaucoma, you may wish to contact:
American
Academy of Ophthalmology
655 Beach Street
San Francisco, CA 94109-7424
(415) 561-8500
http://www.eyenet.org
American Optometric
Association
243 Lindbergh Boulevard
St. Louis, MO 63141
(314) 991-4100
AmOptCCC@aol.com
http://www.aoanet.org
(The)
Glaucoma Foundation
33 Maiden Lane
New York, NY 10038
1-800-452-8266
(212) 285-0080
glaucomafdn@mindspring.com
http://www.glaucoma-foundation.org/info
Glaucoma Research
Foundation
200 Pine Street, Suite 200
San Francisco, CA 94104
1-800-826-6693
(415) 986-3162
http://www.glaucoma.org
National Eye
Institute
2020 Vision Place
Bethesda, MD 20892-3655
(301) 496-5248
2020@nei.nih.gov
http://www.nei.nih.gov
Prevent Blindness
America
500 East Remington Road
Schaumburg, IL 60173
1 (800) 331 -2020
(847) 843-2020
http://prevent-blindness.org
Tips
on Talking to Your Doctor
National Eye
Institute
National Institutes of Health
NIH Publication No. 99-201
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