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.
Forms of glaucoma
Open-angle glaucoma is the most common form. Some people have other types
of the disease.
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
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.
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
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.
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.
Causes and risk factors
| Glaucoma before surgery
How does open-angle glaucoma damage the optic nerve?
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.) 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
Does increased eye pressure mean that I
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.
I develop glaucoma if I have increased eye pressure?
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
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.
Can I develop glaucoma without an
increase in my eye pressure?
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
Who is at risk for glaucoma?
Anyone can develop glaucoma. Some people are at higher risk than others.
Among African Americans, studies show that glaucoma is:
- African Americans over age 40.
- Everyone over age 60, especially Mexican Americans.
- People with a family history of glaucoma.
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
- 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.
What can I do to protect my vision?
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 one to 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. 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
Symptoms and detection
What are the symptoms of glaucoma?
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
Glaucoma can develop in one or both eyes.
How is 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.
Can glaucoma be treated?
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.
- 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 on using your glaucoma eyedrops.
- 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
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.
| Glaucoma after surgery
How should I use my glaucoma eyedrops?
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
- 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
- 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.
What can I do if I already have lost some vision from glaucoma?
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
Source: National Eye
Institute, U.S. National Institutes of Health