Glaucoma

What 

should know 
Glaucoma:


What you should know 


This booklet is for people with glaucoma and their families and 

friends. It provides information about open-angle glaucoma, the 

most common form of glaucoma. This booklet answers questions 

about the cause and symptoms of the disease and discusses 

diagnosis and types of treatment. 

The National Eye Institute (NEI) conducts and supports research 

that leads to sight-saving treatments and plays a key role in 

reducing visual impairment and blindness. The NEI is part of the 

National Institutes of Health (NIH), an agency of the U.S. 

Department of Health and Human Services. 

For more information about the NEI, contact: 

National Eye Institute 

National Institutes of Health 

2020 Vision Place 

Bethesda, MD 20892–3655 

Telephone: 301–496–5248 

E-mail: 2020@nei.nih.gov 

Website: www.nei.nih.gov 
Contents 

What is glaucoma?....................................................................1


What is the optic nerve?............................................................1


How does open-angle glaucoma damage the optic nerve?......2


Does increased eye pressure mean that I have glaucoma? .....3


Can I develop glaucoma if I have increased eye pressure?......3


Can I develop glaucoma without an increase in my


eye pressure?............................................................................4


Who is at risk for open-angle glaucoma?..................................4


What are the symptoms of glaucoma?......................................4


How is glaucoma detected? ......................................................6


Can glaucoma be cured? ..........................................................7


Can glaucoma be treated? ........................................................7


What are some other forms of glaucoma?..............................11


What can I do if I already have lost some vision


from glaucoma?.......................................................................12


What research is being done?.................................................13


What can I do to protect my vision?........................................13


What should I ask my eye care professional?.........................14


Where can I get more information?.........................................16


How should I use my glaucoma eyedrops?.............................19

What is glaucoma? 

Glaucoma is a group of diseases that can damage the eye’s optic 

nerve and result in vision loss and blindness. However, with early 

treatment, you can often protect your eyes against serious vision 

loss. 

What is the optic nerve? 

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. 

1

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


Fluid pathway is shown in blue.


2

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. 

Does increased eye pressure mean

that I have glaucoma? 

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. 

Can 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 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. 

3

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 open-angle glaucoma. 

Who is at risk for 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. 

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. 

What are the symptoms of glaucoma?


At first, open-angle glaucoma has no symptoms. It causes no 

pain. Vision stays normal. 

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 

4

Normal vision 

Same scene as viewed by a person with 

glaucoma 

5

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. 

How is glaucoma detected? 

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. 

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) A tonometer measures 

measures the pressure inside the pressure inside the eye 

eye. Numbing drops may be to detect glaucoma. 

applied to your eye for this test. 

6

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 cured? 

No. There is no cure for glaucoma. Vision lost from the disease 

cannot be restored. 

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 

7

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. For tips on using your glaucoma eyedrops, 

see the inside back cover of this booklet. 

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. 

8

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 followup 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. 

Conventional surgery. Conventional surgery makes a new 

opening for the fluid to leave the eye. (See diagram on the next 

page.) 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. 

9

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. 

10

What are some other forms 

of glaucoma? 

Open-angle glaucoma is the most common form. Some people 

have other types of the disease. 

In 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. 

In 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. 

11

In 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. 

Secondary glaucomas 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. 

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 

services. 

12

What research is being done? 

Through studies in the laboratory and with patients, the National 

Eye Institute is seeking better ways to detect, treat, and prevent 

vision loss in people with glaucoma. For example, researchers 

have discovered genes that could help explain how glaucoma 

damages the eye. 

The NEI also is supporting studies to learn more about who is 

likely to get glaucoma, when to treat people with increased 

pressure, and which treatment to use first. 

What can I do to protect my vision? 

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. 

Medicare covers an annual comprehensive dilated eye exam for 

some people at high risk for glaucoma. These people include 

those with diabetes, those with a family history of glaucoma, and 

African Americans age 50 and older. 

13

What should I ask my eye care 

professional? 

You can protect yourself against vision loss by working in 

partnership with your eye care professional. Ask questions 

and get the information you need to take care of yourself and 

your family. 

What are some questions to ask? 

About my eye disease or disorder... 

• What is my diagnosis? 

• What caused my condition? 

• Can my condition be treated? 

• How will this condition affect my vision now and in the future? 

•	 Should I watch for any particular symptoms and notify you if 

they occur? 

• Should I make any lifestyle changes? 

About my treatment... 

• What is the treatment for my condition? 

• When will the treatment start and how long will it last? 

•	 What are the benefits of this treatment and how successful 

is it? 

•	 What are the risks and side effects associated with this 

treatment? 

14

•	 Are there foods, drugs, or activities I should avoid while I’m on 

this treatment? 

•	If my treatment includes taking medicine, what should I do 

if I miss a dose? 

• Are other treatments available? 

About my tests... 

• What kinds of tests will I have? 

• What can I expect to find out from these tests? 

• When will I know the results? 

• Do I have to do anything special to prepare for any of the tests? 

• Do these tests have any side effects or risks? 

• Will I need more tests later? 

Other suggestions 

•	If you don’t understand your eye care professional’s responses, 

ask questions until you do understand. 

•	 Take notes or get a friend or family member to take notes for you. 

Or, bring a tape recorder to help you remember the discussion. 

•	 Ask your eye care professional to write down his or her 

instructions to you. 

•	 Ask your eye care professional for printed material about your 

condition. 

15

•	If you still have trouble understanding your eye care 

professional’s answers, ask where you can go for more 

information. 

•	 Other members of your health care team, such as nurses and 

pharmacists, can be good sources of information. Talk to them, 

too. 

Today, patients take an active role in their health care. Be an active 

patient about your eye care. 

Where can I get more information? 

For more information about glaucoma, you may wish to 

contact: 

American Academy of Ophthalmology* 

P.O. Box 7424


San Francisco, CA 94120–7424


415–561–8500


1–800–391–3937 (Eye Care America Glaucoma Project)


www.aao.org


American Optometric Association* 

243 North Lindbergh Boulevard


St. Louis, MO 63141–7851


314–991–4100


www.aoa.org


16

The Glaucoma Foundation 

116 John Street, Suite 1605 

New York, NY 10038–3428 

212–285–0080 

E-mail: info@glaucomafoundation.org 

www.glaucoma-foundation.org/info 

Glaucoma Research Foundation 

490 Post Street, Suite 1427 

San Francisco, CA 94102–1305 

1–800–826–6693 

415–986–3162 

www.glaucoma.org 

National Eye Institute* 

National Institutes of Health 

2020 Vision Place 

Bethesda, MD 20892–3655 

301–496–5248 

E-mail: 2020@nei.nih.gov 

www.nei.nih.gov 

Prevent Blindness America 

500 East Remington Road


Schaumburg, IL 60173–4557


1–800–331–2020


847–843–2020


E-mail: info@preventblindness.org


www.preventblindness.org


* These organizations also provide information on low vision. 

17

For more information about low vision services and programs, 

you may wish to contact: 

American Foundation for the Blind 

11 Penn Plaza, Suite 300 

New York, NY 10001–2006 

1–800–232–5463 

212–502–7600 

E-mail: afbinfo@afb.net 

www.afb.org 

Council of Citizens with Low Vision International 

1–800–733–2258 

Lighthouse International 

111 East 59th Street 

New York, NY 10022–1202 

1–800–334–5497 

1–800–829–0500 

212–821–9200 

212–821–9713 (TDD) 

E-mail: info@lighthouse.org 

www.lighthouse.org 

National Association for Visually Handicapped 

22 West 21st Street, 6th Floor


New York, NY 10010–6943


212–889–3141


www.navh.org


18

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 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. 

19 
Revised 9/03 

NIH Publication No: 

National Eye Institute 

National Institutes of Health 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES 

03-651