What is glaucoma?

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.

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.

What are some other forms of glaucoma?

Open-angle glaucoma is the most common form. Some people have other types of the disease.

1. 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.

2. 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.

3. 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.
4. 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.

Causes and Risk Factors

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 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.

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 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.

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 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.

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 remains.

Glaucoma can develop in one or both eyes.

How is glaucoma detected?

Glaucoma is detected through a comprehensive eye exam that includes:

1. 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.
2. 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.
3. 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.
4. Tonometry. An instrument (right) measures the pressure inside the eye. Numbing drops may be applied to your eye for this test.
5. 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.

Treatment

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.

1. 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.

2. 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.

3. 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.

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

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.