This online resource guide provides information about glaucoma. It answers
questions about causes and symptoms, and discusses diagnosis and types of
treatment.
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Glaucoma is a group of diseases that can damage the eye's optic nerve and
result in vision loss and blindness. Glaucoma occurs when the normal fluid
pressure inside the eyes slowly rises. However, with early treatment, you can
often protect your eyes against serious vision loss.
The optic nerve is a bundle of more than 1 million nerve fibers. It connects
the retina to the brain. (See diagram below.) The retina is the light-sensitive
tissue at the back of the eye. A healthy optic nerve is necessary for good
vision.
Open-angle glaucoma is the most common form. Some people have other types of
the disease.
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Low-tension or normal-tension glaucoma. Optic nerve damage and
narrowed side vision occur in people with normal eye pressure. Lowering eye
pressure at least 30 percent through medicines slows the disease in some people.
Glaucoma may worsen in others despite low pressures.
A comprehensive medical history is important in identifying other potential
risk factors, such as low blood pressure, that contribute to low-tension
glaucoma. If no risk factors are identified, the treatment options for
low-tension glaucoma are the same as for open-angle glaucoma.
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Angle-closure glaucoma. The fluid at the front of the eye cannot reach
the angle and leave the eye. The angle gets blocked by part of the iris. People
with this type of glaucoma have a sudden increase in eye pressure. Symptoms
include severe pain and nausea, as well as redness of the eye and blurred
vision. If you have these symptoms, you need to seek treatment immediately.
This is a medical emergency. If your doctor is unavailable, go to the nearest
hospital or clinic. Without treatment to improve the flow of fluid, the eye can
become blind in as few as one or two days. Usually, prompt laser surgery and
medicines can clear the blockage and protect sight.
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Congenital glaucoma. Children are born with a defect in the angle of
the eye that slows the normal drainage of fluid. These children usually have
obvious symptoms, such as cloudy eyes, sensitivity to light, and excessive
tearing. Conventional surgery typically is the suggested treatment, because
medicines may have unknown effects in infants and be difficult to administer.
Surgery is safe and effective. If surgery is done promptly, these children
usually have an excellent chance of having good vision.
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Secondary glaucomas. These can develop as complications of other
medical conditions. These types of glaucomas are sometimes associated with eye
surgery or advanced cataracts, eye injuries, certain eye tumors, or uveitis (eye
inflammation). 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. Corticosteroid drugs
used to treat eye inflammations and other diseases can trigger glaucoma in some
people. Treatment includes medicines, laser surgery, or conventional
surgery.
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In the front of the eye is a space called the anterior chamber. A clear fluid
flows continuously in and out of the chamber and nourishes nearby tissues. The
fluid leaves the chamber at the open angle where the cornea and iris meet. (See
diagram below: Glaucoma before the surgery.) When the fluid reaches the angle, it flows through a spongy
meshwork, like a drain, and leaves the eye.
Sometimes, when the fluid reaches the angle, it passes too slowly through the
meshwork drain. As the fluid builds up, the pressure inside the eye rises to a
level that may damage the optic nerve. When the optic nerve is damaged from
increased pressure, open-angle glaucoma--and vision loss--may result. That's why
controlling pressure inside the eye is important.
Not necessarily. Increased eye pressure means you are at risk for glaucoma,
but does not mean you have the disease. A person has glaucoma only if the optic
nerve is damaged. If you have increased eye pressure but no damage to the optic
nerve, you do not have glaucoma. However, you are at risk. Follow the advice of
your eye care professional.
Not necessarily. Not every person with increased eye pressure will develop
glaucoma. Some people can tolerate higher eye pressure better than others. Also,
a certain level of eye pressure may be high for one person but normal for
another.
Whether you develop glaucoma depends on the level of pressure your optic
nerve can tolerate without being damaged. This level is different for each
person. That's why a comprehensive dilated eye exam is very important. It can
help your eye care professional determine what level of eye pressure is normal
for you.
Yes. Glaucoma can develop without increased eye pressure. This form of
glaucoma is called low-tension or normal-tension glaucoma. It is not as common
as open-angle glaucoma.
Anyone can develop glaucoma. Some people are at higher risk than others. They
include:
- African Americans over age 40.
- Everyone over age 60, especially Mexican Americans.
- People with a family history of glaucoma.
Among African Americans, studies show that glaucoma is:
- Five times more likely to occur in African Americans than in Caucasians.
- About four times more likely to cause blindness in African Americans than in
Caucasians.
- Fifteen times more likely to cause blindness in African Americans between
the ages of 45-64 than in Caucasians of the same age group.
A comprehensive dilated eye exam can reveal more risk factors, such as high
eye pressure, thinness of the cornea, and abnormal optic nerve anatomy. In some
people with certain combinations of these high-risk factors, medicines in the
form of eyedrops reduce the risk of developing glaucoma by about half.
Medicare covers an annual comprehensive dilated eye exam for some people at
high risk for glaucoma.
Studies have shown that the early detection and treatment of glaucoma, before
it causes major vision loss, is the best way to control the disease. So, if you
fall into one of the high-risk groups for the disease, make sure to have your
eyes examined through dilated pupils every two years by an eye care
professional.
If you are being treated for glaucoma, be sure to take your glaucoma medicine
every day. See your eye care professional regularly.
You also can help protect the vision of family members and friends who may be
at high risk for glaucoma--African Americans over age 40; everyone over age 60,
especially Mexican Americans; and people with a family history of the disease.
Encourage them to have a comprehensive dilated eye exam at least once every two
years. Remember: Lowering eye pressure in glaucoma's early stages slows
progression of the disease and helps save vision.
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At first, there are no symptoms. Vision stays normal, and there is no
pain.
However, as the disease progresses, a person with glaucoma may notice his or
her side vision gradually failing. That is, objects in front may still be seen
clearly, but objects to the side may be missed.
As glaucoma remains untreated, people may miss objects to the side and out of
the corner of their eye. Without treatment, people with glaucoma will slowly
lose their peripheral (side) vision. They seem to be looking through a tunnel.
Over time, straight-ahead vision may decrease until no vision remains.
Glaucoma can develop in one or both eyes.
Normal
vision | 
Same scene as
viewed by a person with glaucoma |
Glaucoma is detected through a
comprehensive eye exam that includes:
- Visual acuity test. This eye chart test measures how well you see at
various distances. A tonometer measures pressure inside the eye to detect
glaucoma.
- Visual field test. This test measures your side (peripheral) vision.
It helps your eye care professional tell if you have lost side vision, a sign of
glaucoma.
- Dilated eye exam. Drops are placed in your eyes to widen, or dilate,
the pupils. Your eye care professional uses a special magnifying lens to examine
your retina and optic nerve for signs of damage and other eye problems. After
the exam, your close-up vision may remain blurred for several hours.
- Tonometry. An instrument (right) measures the pressure inside the
eye. Numbing drops may be applied to your eye for this test.
- Pachymetry. A numbing drop is applied to your eye. Your eye care
professional uses an ultrasonic wave instrument to measure the thickness of your
cornea.
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Yes. Immediate treatment for early stage, open-angle glaucoma can delay
progression of the disease. That's why early diagnosis is very important.
Glaucoma treatments include medicines, laser trabeculoplasty, conventional
surgery, or a combination of any of these. While these treatments may save
remaining vision, they do not improve sight already lost from glaucoma.
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Medicines. Medicines, in the form of eyedrops or pills, are the most
common early treatment for glaucoma. Some medicines cause the eye to make less
fluid. Others lower pressure by helping fluid drain from the eye.
Before you begin glaucoma treatment, tell your eye care professional about
other medicines you may be taking. Sometimes the drops can interfere with the
way other medicines work.
Glaucoma medicines may be taken several times a day. Most people have no
problems. However, some medicines can cause headaches or other side effects. For
example, drops may cause stinging, burning, and redness in the eyes. Many drugs
are available to treat glaucoma. If you have problems with one medicine, tell
your eye care professional. Treatment with a different dose or a new drug may be
possible.
Because glaucoma often has no symptoms, people may be tempted to stop taking,
or may forget to take, their medicine. You need to use the drops or pills as
long as they help control your eye pressure. Regular use is very important. Make
sure your eye care professional shows you how to put the drops into your eye.
See tips (hyperlink to "How should I use my glaucoma eyedrops?") on using your
glaucoma eyedrops.
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Laser trabeculoplasty. Laser trabeculoplasty helps fluid drain out of
the eye. Your doctor may suggest this step at any time. In many cases, you need
to keep taking glaucoma drugs after this procedure.
Laser trabeculoplasty is performed in your doctor's office or eye clinic.
Before the surgery, numbing drops will be applied to your eye. As you sit facing
the laser machine, your doctor will hold a special lens to your eye. A
high-intensity 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 several evenly spaced burns that stretch the drainage holes in the
meshwork. This allows the fluid to drain better.
Like any surgery, laser surgery can cause side effects, such as inflammation.
Your doctor may give you some drops to take home for any soreness or
inflammation inside the eye. You need to make several follow-up visits to have
your eye pressure monitored.
If you have glaucoma in both eyes, only one eye will be treated at a time.
Laser treatments for each eye will be scheduled several days to several weeks
apart.
Studies show that laser surgery is very good at reducing the pressure in some
patients. However, its effects can wear off over time. Your doctor may suggest
further treatment.
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Conventional surgery. Conventional surgery makes a new opening for the
fluid to leave the eye. (See diagram.) Your doctor may suggest this treatment at
any time. Conventional surgery often is done after medicines and laser surgery
have failed to control pressure.
Conventional surgery is performed in an eye clinic or hospital. Before the
surgery, you will be given medicine to help you relax. Your doctor will make
small injections around the eye to numb it. A small piece of tissue is removed
to create a new channel for the fluid to drain from the eye.
For several weeks after the surgery, you must put drops in the eye to fight
infection and inflammation. These drops will be different from those you may
have been using before surgery.
As with laser surgery, conventional surgery is performed on one eye at a
time. Usually the operations are four to six weeks apart. Conventional surgery
is about 60 to 80 percent effective at lowering eye pressure. If the new
drainage opening narrows, a second operation may be needed. Conventional surgery
works best if you have not had previous eye surgery, such as a cataract
operation.
In some instances, your vision may not be as good as it was before
conventional surgery. Conventional surgery can cause side effects, including
cataract, problems with the cornea, and inflammation or infection inside the
eye. The buildup of fluid in the back of the eye may cause some patients to see
shadows in their vision. If you have any of these problems, tell your doctor so
a treatment plan can be developed.
Conventional surgery makes a new opening for the fluid to leave the
eye.
If eyedrops have been prescribed for treating your glaucoma, you need to use
them properly and as instructed by your eye care professional. Proper use of
your glaucoma medication can improve the medicine's effectiveness and reduce
your risk of side effects. To properly apply your eyedrops, follow these
steps:
- First, wash your hands.
- Hold the bottle upside down.
- Tilt your head back.
- Hold the bottle in one hand and place it as close as possible to the eye.
- With the other hand, pull down your lower eyelid. This forms a pocket.
- Place the prescribed number of drops into the lower eyelid pocket. If you
are using more than one eyedrop, be sure to wait at least five minutes before
applying the second eyedrop.
- Close your eye OR press the lower lid lightly with your finger for at least
one minute. Either of these steps keeps the drops in the eye and helps prevent
the drops from draining into the tear duct, which can increase your risk of side
effects
If you have lost some sight from glaucoma, ask your eye care professional
about low vision services and devices that may help you make the most of your
remaining vision. Ask for a referral to a specialist in low vision.
Many community organizations and agencies offer information about low vision
counseling, training, and other special services for people with visual
impairments. A nearby school of medicine or optometry may provide low vision
services.
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A large amount of research is being done in the U.S. to learn what causes
glaucoma and to improve its diagnosis and treatment. For instance, the National
Eye Institute (NEI) is funding a number of studies to find out what causes fluid
pressure to increase in the eye. By learning more about this process, doctors
may be able to find the exact cause of the disease and learn better how to
prevent and treat it. The NEI also supports clinical trials of new drugs and
surgical techniques that show promise against glaucoma.
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Post Date:
Sun Nov 12 2006 12:29:02 GMT+0800 (Phils.)
Posted For the Public By: D. K. Mangusan Jr., PTRP
Image & Photo Credit: NEI/NIH
Content Source: National Eye Institute/ National Institutes of Health
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This online resource guide provides information about cataracts. It answers
questions about causes and symptoms, and discusses diagnosis and types of
treatment. It was adapted from Don't Lose Sight of Glaucoma (NIH
Publication No. 96-3251) and Glaucoma: What You Should Know (NIH
Publication No. 03-651).
