Glaucoma
An Introduction to the
"Silent Thief of Vision"
Glaucoma is sometimes called
the silent thief because it can
slowly steal your sight before
you realize anything's wrong.
It's a leading cause of vision
loss.
The most common form of
glaucoma, primary open-angle
glaucoma, develops gradually,
giving no warning signs. Many
people aren't even aware they
have an eye problem until their
vision is extensively
compromised.
Glaucoma is not just one
disease, but a group of them.
The common feature of these
diseases is damage to the optic
nerve, usually accompanied by an
abnormally high pressure inside
your eyeball.
The optic nerve is a bundle
of more than a million nerve
fibers at the back of your eye.
It's like an electric cable made
up of thousands of individual
wires carrying the images from
the inside back wall of your
eyeball (retina) to your brain.
Blind spots develop in your
visual field when the optic
nerve deteriorates, usually
starting with your peripheral
(side) vision. If left
untreated, glaucoma may lead to
blindness in both eyes.
Fortunately, medical advances
have made it easier to diagnose
and treat glaucoma. If detected
and treated early, glaucoma need
not cause even moderate vision
loss. But having glaucoma does
mean regular monitoring and
treatment for the rest of your
life.
Signs and symptoms
Glaucoma occurs in several
types, and signs and symptoms
vary depending on the type of
glaucoma you have.
Primary open-angle
glaucoma progresses
with few or no symptoms until
the condition reaches an
advanced stage. As increased eye
pressure continues to damage
your optic nerve, you lose more
and more of your peripheral
vision. If glaucoma is left
untreated, you can develop
tunnel vision and eventually
lose all sight. Open-angle
glaucoma usually affects both
eyes, although at first you may
have vision loss in just one
eye.
Acute angle-closure
glaucoma develops
suddenly in response to a rapid
rise in eye pressure. Permanent
vision loss can occur within a
day of the attack, so it
requires immediate medical
attention. An attack often
happens in the evening or in a
darkened room when the light is
dim and your pupils have become
relatively dilated. Pain may be
severe. Signs and symptoms
include:
- Blurred vision
- Halos around lights
- Reddening of the eye
- Severe eye pain
- Nausea and vomiting
Both open-angle and
angle-closure glaucoma can be
primary or secondary conditions.
They're called primary when the
cause is unknown. They're called
secondary when the condition can
be traced to a known cause, such
as an injury or an eye disease.
Signs and symptoms of secondary
glaucoma vary and depend on
what's causing the glaucoma.
Causes
|
Movement of fluid in
the eye
|
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Open-angle glaucoma
|
|
Angle-closure
glaucoma
|
Internal pressure in your
eye, called intraocular
pressure, allows your eye to
hold its shape and function
properly. Intraocular pressure
is like air in a balloon — too
much pressure inside the balloon
affects its shape and may even
cause it to pop. In the case of
your eye, too much pressure can
damage the optic nerve.
Fluids inside your eye help
maintain the intraocular
pressure. These fluids are the
vitreous, which
fills the vitreous cavity at the
back of your eye, and the
aqueous humor,
which fills the anterior chamber
at the front of your eye.
Aqueous humor is continuously
produced and circulated through
the anterior chamber before
draining out of your eye. This
continuous flow of fluid
nourishes the lens and the
cornea and also removes unwanted
debris. A healthy eye produces
aqueous humor at the same rate
that it drains fluid, thus
maintaining a normal pressure.
Your eyes' drainage
system
Aqueous humor exits your eye
through a drainage system
located at the angle formed
where the iris and the cornea
meet. Here it passes through a
sieve-like system of spongy
tissue called the trabecular
meshwork and drains into a
channel called Schlemm's canal.
The fluid then merges into your
bloodstream.
When the drainage system
doesn't function properly — for
example, if the trabecular
meshwork becomes clogged — the
aqueous humor can't filter out
of the eye at its normal rate,
and pressure builds within your
eye. For reasons that doctors
don't completely understand,
increased eye pressure is often
associated with gradual damage
to the nerve fibers that make up
the optic nerve.
Types of glaucoma
-
Primary open-angle
glaucoma. This
form, also called chronic
open-angle glaucoma,
accounts for most cases of
the disease. Although the
drainage angle formed by the
cornea and the iris remains
open, the aqueous humor
drains too slowly. This
leads to fluid backup and a
gradual buildup of pressure
within your eye. Damage to
the optic nerve is so slow
and painless that a large
portion of your vision can
be lost before you're even
aware of a problem.
The
exact cause of primary
open-angle glaucoma remains
unknown. It may be that the
aqueous humor drains or is
absorbed less efficiently
with age, but not all older
adults get this form of
glaucoma. About 2 percent of
Americans older than age 40
have elevated eye pressure.
For Americans older than 70,
the number is 8 percent.
-
Angle-closure.
Angle-closure glaucoma, also
called closed-angle
glaucoma, is a less common
form of the disease. This
type of glaucoma is a
medical emergency that can
cause vision loss within a
day of its onset.
It
occurs when the drainage
angle formed by the cornea
and the iris closes or
becomes blocked. Many people
with this type of glaucoma
have a very narrow drainage
angle, which may be an
abnormality from birth. As
you get older, your lens
becomes larger, pushing your
iris forward and narrowing
the space between the iris
and the cornea.
Whether the narrow
drainage angle is an
abnormality from birth or a
result of aging, as this
angle narrows, the iris gets
closer to the trabecular
meshwork. If it gets too
close, the aqueous humor
can't exit through the
trabecular meshwork,
resulting in a buildup of
fluid and an increase in eye
pressure.
Angle-closure glaucoma
can be chronic (progressing
gradually) or acute
(appearing suddenly). The
acute form occurs when the
iris is forced up against
the trabecular meshwork and
completely blocks the
drainage of the aqueous
humor.
Angle-closure glaucoma is
more common among farsighted
people. Normal aging also
may cause angle blockage.
If you have a narrow
drainage angle and your
pupils become dilated, the
angle may close and cause a
sudden increase in eye
pressure. This attack of
acute angle-closure glaucoma
requires immediate
treatment. Although an acute
attack often affects only
one eye, the other eye is at
risk of an attack as well.
Several factors can cause
your pupils to dilate,
including darkness or dim
light, stress or excitement,
and certain medications.
These medications include
antihistamines, tricyclic
antidepressants and eyedrops
used to dilate your pupils.
However, dilating eyedrops
may not cause the angle to
close until several hours
after the drops are put in
your eyes.
-
Secondary.
Both open-angle and
angle-closure glaucoma can
be primary or secondary
conditions. They're called
primary when the cause of
the condition is unknown.
They're called secondary
when the condition can be
traced to a known cause,
such as an injury or an eye
disease. Secondary glaucoma
may be caused by a variety
of medical conditions,
medications, physical
injuries, and eye
abnormalities or
deformities. Infrequently
eye surgery can be
associated with secondary
glaucoma.
-
Low-tension.
Low-tension glaucoma is a
poorly understood, though
not uncommon, form of the
disease. In this form, eye
pressure remains within what
is ordinarily thought to be
the normal range, but the
optic nerve is damaged
nevertheless. Why this
happens is unknown.
Some
experts believe that people
with low-tension glaucoma
may have an abnormally
sensitive optic nerve or a
reduced blood supply to the
optic nerve caused by a
condition such as
atherosclerosis, a hardening
of the arteries caused by
accumulation of fatty
deposits (plaques) and other
substances. Under these
circumstances even normal
pressure on the optic nerve
seems to be enough to cause
damage.
Doctors don't completely
understand the underlying causes
of glaucoma. Although glaucoma
is normally associated with
increased eye pressure, people
with normal or low eye pressure
can experience vision loss. And
people with higher than normal
eye pressure may never
experience optic nerve damage.
Risk factors
If the internal pressure in
your eye (intraocular pressure)
is higher than what's considered
normal, you're at increased risk
of developing glaucoma, though
not everyone with elevated
intraocular pressure develops
the disease. This makes it
difficult to predict who will
get glaucoma.
Certain other factors
increase your risk. Because
chronic forms of glaucoma can
destroy vision before any signs
or symptoms are apparent, be
aware of these factors:
-
Age. Age is
a large risk factor in the
development of glaucoma.
Everyone older than 60 is at
increased risk of the
disorder. For blacks
however, the increase in
risk becomes apparent
earlier, after age 40.
-
Race.
Blacks are significantly
more likely to get glaucoma
than are whites, and they
are much more likely to
suffer permanent blindness
as a result.
Mexican-Americans also face
an increased risk.
Asian-Americans are at
higher risk of angle-closure
glaucoma, and
Japanese-Americans are more
prone to low-tension
glaucoma. The reasons for
these differences aren't
clear.
-
Family history of
glaucoma. If you
have a family history of
glaucoma, you have a much
greater risk of developing
glaucoma. Glaucoma may have
a genetic link, meaning
there's a defect in one or
more genes that may cause
certain individuals to be
more susceptible to the
disease.
-
Medical conditions.
Diabetes increases your risk
of developing glaucoma. A
history of high blood
pressure or heart disease
also can increase your risk,
as can hypothyroidism.
Routine use of coffee has
recently been found to be
associated with a slight
increase in intraocular
pressure.
-
Physical injuries.
Severe trauma, such as being
hit in the eye, can result
in increased eye pressure.
Injury can also dislocate
the lens, closing the
drainage angle. Other risk
factors include retinal
detachment, eye tumors, and
eye inflammations such as
chronic uveitis and iritis.
Certain types of eye surgery
also may trigger secondary
glaucoma.
-
Nearsightedness.
Being nearsighted, which
generally means that objects
in the distance look fuzzy
without glasses or contacts,
increases the risk of
developing glaucoma.
-
Prolonged
corticosteroid use.
Using corticosteroids for
prolonged periods of time
appears to put you at risk
of getting secondary
glaucoma.
-
Eye abnormalities.
Structural abnormalities of
the eye can lead to
secondary glaucoma. For
example, pigmentary glaucoma
is a form of secondary
glaucoma caused by pigment
granules being released from
the back of the iris. These
granules can block the
trabecular meshwork.
When to seek medical advice
Primary open-angle glaucoma
gives few warning signs or
symptoms until permanent damage
has already occurred. That's why
regular eye exams are the key to
detecting glaucoma early enough
for successful treatment.
It's best to have routine eye
checkups every two to four years
after age 40 and every one to
two years after age 65. Because
African-Americans have a much
higher risk of glaucoma,
screening should begin every
three to five years from age 20
to 29, and every two to four
years after age 30.
Don't wait for problems of
any kind to occur. If you have
one or more risk factors for
glaucoma, talk to your doctor
about scheduling regular eye
exams. Some tests can be
performed by your regular
doctor, but others need to be
done by an eye-care specialist.
In addition, be alert for
signs or symptoms of an acute
angle-closure glaucoma attack,
such as a severe headache or
pain in your eye or eyebrow,
nausea, blurred vision, or
rainbow halos around lights. If
you experience any of these
problems, seek immediate care at
your local hospital emergency
room.
If you've received a
diagnosis of glaucoma, establish
a regular schedule of
examinations with your doctor to
be sure your treatment is
helping maintain a safe pressure
in your eyes.
Screening and diagnosis
If your doctor suspects that
you have glaucoma, he or she may
perform a series of tests to
detect any signs of damage.
Tests include:
-
Tonometry.
Tonometry is a simple,
painless procedure that
measures your intraocular
pressure. It is usually the
initial screening test for
glaucoma.
Two common
techniques are
air-puff tonometry
and applanation
tonometry. Air-puff
tonometry uses a puff of air
to measure the amount of
force needed to indent your
cornea. An applanation
tonometer is a sophisticated
device that's usually fitted
to a slit lamp. Slit lamps
use an intense line of light
— a slit — providing
illumination of the cornea,
iris, lens and anterior
chamber, and allowing your
doctor a good view of these
structures.
With tonometry, your
doctor numbs your eyes with
drops and has you sit behind
the slit lamp, where a small
flat-tipped cone pushes
lightly against your
eyeball. The force required
to flatten (applanate) a
small area of your cornea
translates into a measure of
your intraocular pressure .
Average normal eye
pressures range from 10 to
21 or 22 millimeters of
mercury (mm Hg), though most
pressures are within 14 to
16 mm Hg. Doctors consider
anyone with eye pressure
greater than 22 mm Hg to be
at risk of developing
glaucoma and in need of
careful monitoring for early
signs of glaucoma.
Tonometry readings vary
somewhat depending on a
variety of factors including
the thickness of your
corneas and whether you've
had laser surgery on your
eyes. For these reasons,
newer technologies are being
investigated to improve the
standard applanation
instrument and obtain more
accurate intraocular eye
pressure measurements.
-
Test for optic nerve
damage. To check
the fibers in your optic
nerve, your eye doctor uses
an instrument called an
ophthalmoscope or
biomicroscope, which enables
him or her to look directly
through the pupil to the
back of your eye. Your
doctor may also use laser
light and computers to
create a three-dimensional
image of your optic nerve.
This can reveal slight
changes that may indicate
the beginnings of glaucoma.
Your doctor may also make a
detailed drawing of your
optic nerves and take
photographs of the optic
nerves in order to monitor
any changes that might occur
at future visits.
-
Visual field test.
To check how your visual
field has been affected by
glaucoma, your doctor uses a
perimetry test. One method,
known as tangent screen
perimetry, requires you to
look at a screen with a
target in the center. Your
eye doctor or a technician
manipulates a small object
on a wand at different
locations in your visual
field. You indicate whenever
you see the object come into
view. By repeating this
process over and over again,
your entire visual field can
be mapped.
-
Pachymetry.
Your eyes are numbed for
this test, which uses an
ultrasonic-wave instrument
to gauge the thickness of
each cornea. The thickness
of your corneas is an
important factor for
accurately diagnosing
glaucoma. If you have thick
corneas, your eye pressure
reading may seem high even
though you don't have
glaucoma. Conversely, people
with thin corneas can have
low pressure readings, but
have glaucoma.
-
Other tests.
To distinguish between
open-angle glaucoma and
angle-closure glaucoma, your
eye doctor may use a
technique called gonioscopy
(go-ne-OS-kuh-pe), in which
a special lens with an
angled mirror is placed on
your eye to inspect the
drainage angle. Another
test, tonography, can
measure how fast fluid
drains through the
trabecular meshwork.
To establish a diagnosis of
glaucoma, several factors must
be present:
- Elevated intraocular
pressure
- Areas of vision loss
- Damage to your optic
nerve
In glaucoma, the optic disk
shows visible signs of damage.
The optic disk is the area where
all of the nerve fibers come
together at the back of your eye
before exiting your eyeball. An
optic disk that has been
affected by glaucoma appears
indented, or excavated, as if
someone scooped out part of the
center of the disk. This
condition is known as cupping.
The normal contour and color of
the disk may also be affected by
the loss of nerve fibers.
Treatment
The treatment of glaucoma is
aimed at reducing intraocular
pressure by improving aqueous
outflow, reducing the production
of aqueous, or both. Doctors
accomplish these treatment goals
with eyedrops, systemic
medications, laser treatment,
surgery, or a combination of
treatments.
If your doctor determines
that you have elevated
intraocular pressure , an
excavated optic disk and loss of
visual field, you'll likely be
treated for glaucoma. If you
have only slightly elevated eye
pressure, an undamaged optic
nerve and no visual field loss,
you may not need treatment, but
your doctor may advise more
frequent examinations to detect
any future changes. If you have
signs of optic nerve damage and
visual field loss, even if your
eye pressure is in the normal
range, you may need treatment to
lower eye pressure further,
which may help slow the
progression of glaucoma.
Glaucoma can't be cured, and
damage caused by the disease
can't be reversed. But with
treatment, glaucoma can be
controlled. Eyedrops, oral
medications and surgical
procedures can prevent or slow
further damage.
Lifelong treatment
Having glaucoma means you'll
need to continue treatment for
the rest of your life. Because
the disease can progress or
change without your being aware
of it, your treatment may need
to be adjusted over time.
Regular checkups and adherence
to a treatment plan may seem
burdensome, but they're
essential to prevent vision
loss.
Keeping your eye pressure
under control can prevent
further damage to the optic
nerve and continued loss of your
visual field. Your eye doctor
may focus on lowering your
intraocular pressure to a level
that's unlikely to cause further
optic nerve damage. This level
is often referred to as the
target pressure and will
probably be a range rather than
a single number. Target pressure
differs for each person,
depending on the extent of the
damage and other factors. Your
target pressure may change over
the course of your lifetime.
Topical eye medications are
the most common early treatment
for glaucoma. Reducing the
pressure in the eyes has been
shown to reduce the progression
of visual field loss. Standard
practice has been to move on to
surgery if medications are
ineffective or if the glaucoma
patient has difficulty in
adhering to the medical therapy
recommendations. However,
surgery is also a relatively
safe and effective initial
treatment.
Eyedrops
Glaucoma treatment often starts
with medicated eyedrops. Doctors
prescribe several types of
drops. Be sure to use the drops
exactly as prescribed to control
your intraocular pressure .
Skipping even a few doses can
cause damage to the optic nerve
to worsen. Some drops need to be
applied several times each day,
and others must be used just
once a day. Inform your doctor
of all other medications you're
taking, to avoid any undesirable
drug interactions.
Because some of the eyedrops
are absorbed into your
bloodstream, you may experience
side effects unrelated to your
eyes. To minimize this
absorption, close your eyes for
one to two minutes after putting
the drops in. Press lightly at
the corner of your eye near your
nose to close the tear duct, and
wipe off any unused drops from
your eyelid. Your doctor may
prescribe more than one type of
eyedrop. If you're using more
than one, ask your doctor how
long to wait between
applications.
The types of eyedrops that
doctors most commonly prescribe
include:
-
Beta blockers.
These reducethe production
of aqueous humor. Examples
include levobunolol
(Betagan), timolol (Betimol,
Timoptic), carteolol
(Ocupress), betaxolol
(Betoptic) and metipranolol
(OptiPranolol). Possible
side effects include
difficulty breathing, slowed
pulse, hair loss, lower
blood pressure, impotence,
fatigue, weakness,
depression and memory loss.
If you have asthma,
bronchitis or emphysema or
if you have diabetes and use
insulin, medications other
than beta blockers may be
recommended because beta
blockers may worsen
breathing problems.
-
Alpha-adrenergic
agents. These
reduce the production of
aqueous humor. Examples
includeapraclonidine
(Iopidine) and brimonidine
(Alphagan). Possible side
effects include fatigue,
dizziness, red, itchy or
swollen eyes, dry mouth and
allergic reactions.
-
Carbonic anhydrase
inhibitors. These
medications, which include
dorzolamide (Trusopt) and
brinzolamide (Azopt),
reducethe amount of aqueous
humor. Possible side effects
include frequent urination
and a tingling sensation in
the fingers and toes, but
these occur more frequently
when a carbonic anhydrase
inhibitor is taken orally.
If you have an allergy or
sensitivity to sulfa drugs,
don't use these medications
unless there's no
alternative.
-
Prostaglandin
analogues. These
eyedrops increase theoutflow
of aqueous humor. These
hormone-like substances,
which include latanoprost
(Xalatan), bimatoprost
(Lumigan) and travoprost
(Travatan), may be used in
conjunction with a drug that
reduces production of
aqueous humor. There has
been a trend away from using
these agents as a first line
therapy for glaucoma.
Possible side effects
include mild reddening and
stinging of the eyes and
darkening of the iris,
changes in the pigment of
the eyelid skin, and blurred
vision from swelling of the
retina.
-
Miotics.
Miotics, such as pilocarpine
(Isopto Carpine, Pilocar),
increase the outflow of
aqueous humor. Possible side
effects include pain around
or inside the eyes, brow
ache, blurred or dim vision,
nearsightedness, allergic
reactions, a stuffy nose,
sweating, increased
salivation, and occasional
digestive problems.
-
Epinephrine
compounds. These
also increasethe outflow of
aqueous humor. Possible side
effects include red eyes,
allergic reactions,
palpitations, an increase in
blood pressure, headache and
anxiety.
Oral medications
If eyedrops alone don't bring
your eye pressure down to the
desired level, your doctor may
also prescribe an oral
medication. Doctors commonly
prescribe carbonic anhydrase
inhibitors, such as
acetazolamide and methazolamide,
for glaucoma. Take these pills
with meals to reduce side
effects. You can help to
minimize the potassium loss that
these medications can cause by
adding bananas and apple juice
to your diet.
When you first start taking
these oral medications, you may
experience a frequent need to
urinate and a tingling sensation
in your fingers and toes. After
several days, these symptoms
usually disappear. Other
possible side effects of
carbonic anhydrase inhibitors
include rashes, depression,
fatigue, kidney stones,
lethargy, stomach upset, a
metallic taste in carbonated
beverages, impotence and weight
loss.
Neuroprotective drugs
Lowering the intraocular
pressure provides only a partial
solution when it comes to
preserving vision in people with
glaucoma. Several clinical
trials are under way to learn if
certain drugs may help protect
the optic nerve from damage
associated with glaucoma. Some
are investigating the potential
neuroprotective effects of
brimonidine (Alphagan), a
topical eye medication that may
already be prescribed for
glaucoma. Another is
investigating the potential
neuroprotective effect of
memantine, an oral medication
generally used in the treatment
of Alzheimer's disease.
Surgery
You may need surgery to treat
glaucoma if you can't tolerate
medications or if they're
ineffective. Doctors use several
types of surgery to treat
glaucoma:
- Laser surgery.
In the last couple of
decades, a procedure called
trabeculoplasty (truh-BEK-u-lo-plas-te)
has been used increasingly
in the treatment of
open-angle glaucoma. The
doctor uses a high-energy
laser beam to shrink part of
the trabecular meshwork,
which causes other parts of
the meshwork to stretch and
open up. This helps aqueous
humor drain more easily from
the eye.
This type of
laser surgery is an office
procedure that takes 10 to
20 minutes. You'll be given
an anesthetic eyedrop,
seated at a slit lamp and
fitted with a special lens
on your eye. The doctor aims
the laser through the lens
at the trabecular meshwork
and applies burns to it. You
will see bright flashes of
light.
Usually, you can
immediately resume normal
activities without
discomfort. The doctor will
usually check your eye
pressure one to two hours
after the procedure and
several times in the
following weeks. It may take
a few weeks before the full
effect of the surgery
becomes apparent.
In almost all cases,
laser surgery for glaucoma
initially lowers intraocular
pressure. After time,
however, intraocular
pressure may begin to
increase.
- Conventional
surgery. If
eyedrops and laser surgery
aren't effective in
controlling your eye
pressure, you may need an
operation called a filtering
procedure, usually in the
form of a trabeculectomy
(truh-bek-u-LEK-tuh-me).
This procedure is done in a
hospital or an outpatient
surgery center.
You'll
receive medication to help
you relax and eyedrops and
usually an injection of
anesthetic to numb your eye.
Using delicate instruments
under an operating
microscope, your surgeon
creates an opening in the
sclera — the white of your
eye — and removes a small
piece of the trabecular
meshwork.
The aqueous humor can now
freely leave the eye through
this hole. As a result your
eye pressure will be
lowered. The hole is covered
by the conjunctiva, so
there's not an open hole in
your eye. This procedure
works best if you haven't
had any previous eye
surgery.
Your doctor will check
your eye during several
follow-up visits. You'll
need to use antibiotic and
anti-inflammatory eyedrops
for some time after the
operation to fight infection
and scarring of the newly
created drainage opening.
Scarring is a particular
problem for young adults,
blacks and people who have
had cataract surgery.
Although glaucoma surgery
may preserve current vision,
it can't restore already
lost vision. Sometimes a
single surgical procedure
may not lower eye pressure
enough, in which case you'll
need to continue using
glaucoma drops or have
another trabeculectomy
operation.
- Drainage
implants. Another
type of operation, called
drainage implant surgery,
may be an option for people
with secondary glaucoma or
for children with glaucoma.
Like the trabeculectomy,
drainage implant surgery is
performed at a hospital or
an outpatient clinic. You'll
receive medication to help
you relax and eyedrops and
an anesthetic to numb your
eye. Then the doctor inserts
a small silicone tube in
your eye to help drain
aqueous humor.
After the
surgery you'll wear an eye
patch for 24 hours and use
eyedrops for several weeks
to fight infection and
scarring. Your doctor will
check your eyes several
times in the weeks that
follow.
Possible complications from
glaucoma surgery may include
infection, bleeding, eye
pressure that remains too high
or too low, and, potentially,
loss of vision. Having eye
surgery may also speed up the
development of cataracts. Most
of these complications can be
effectively treated.
Treating acute
angle-closure glaucoma
Acute angle-closure glaucoma is
a medical emergency. When you
come in with this condition,
doctors may administer several
medications to reduce eye
pressure as quickly as possible.
You'll also likely have a laser
procedure called iridotomy (ir-ih-DOT-uh-me).
In this procedure, a laser
beam creates a small hole in
your iris to allow aqueous humor
to flow more freely into the
anterior chamber where it then
has normal access to the
trabecular meshwork. Once
aqueous humor can reach the
trabecular meshwork again, the
fluid can drain as it normally
does. Many doctors recommend an
iridotomy on the other eye at a
later date because of the high
risk that it too will have an
attack within the next few
years.
Prevention
Until recently, there was no
proven way to prevent glaucoma.
But a large multicenter trial,
supported by the National Eye
Institute, found that when
glaucoma eyedrops were given
daily to people with elevated
eye pressure (above 24 mm Hg),
they reduced eye pressure an
average of 22 percent. More
important, the researchers
discovered that daily use of
eyedrops can reduce the risk of
developing glaucoma by nearly
half in blacks with elevated eye
pressure.
Another study found that
cholesterol-lowering medications
reduced the risk of open-angle
glaucoma, especially for people
who already have cardiovascular
disease. Although this may be an
added benefit for those already
taking these medications to
reduce their cholesterol levels,
more studies need to be done to
confirm the reduction in risk of
glaucoma.
Frequent monitoring
Regular checkups can help detect
the disease in its early stages
before irreversible damage has
occurred. As a general rule,
have eye exams every two to four
years if you're between the ages
of 40 and 65, and every one to
two years if you're older than
65.
Your doctor will likely
recommend more frequent
monitoring if you're at
increased risk of developing
glaucoma. For example, a family
history of glaucoma puts you at
increased risk of developing
glaucoma and is a reason for
more frequent monitoring. You
may also need even more frequent
checkups if you have received a
diagnosis of abnormally high
intraocular pressure or have a
history of serious eye injury.
Self-care
The most important thing you
can do if you have glaucoma is
take your medications exactly as
prescribed. Frequent eye exams
will help your doctor monitor
your eye pressure and keep you
and your doctor aware of any
changes in your vision.
Other self-care tips:
-
Maintain a healthy
diet. Eat a healthy
diet full of fruits and
vegetables to ensure that
you get enough vitamins and
minerals. Some that are
especially important to your
eye health include vitamin
A, vitamin C, vitamin E,
zinc and copper. Drink
fluids in small amounts over
the course of a day.
Drinking a quart or more of
any liquid within a short
time may increase eye
pressure. Limiting caffeine
to low or moderate levels
may be helpful.
-
Exercise regularly.
People with open-angle
glaucoma who exercise
regularly — at least three
times a week — may be able
to moderately reduce their
eye pressure. However,
angle-closure glaucoma isn't
affected by exercise, and
people with pigmentary
glaucoma, a form of
secondary glaucoma, may
experience increased eye
pressure after exercise.
Also, yoga and other
exercises that put you in a
head-down position may
increase the pressure in
your eyes. Talk to your
doctor about an appropriate
exercise program.
-
Don't depend on
herbal remedies for the
primary care of glaucoma.
A number of herbal
supplements, such as
bilberry, are advertised as
glaucoma remedies. Bilberry
has not been proved
effective in preventing or
treating glaucoma and should
never be used in place of
proven therapies. Always be
cautious about herbal
supplements and discuss them
with your doctor before
trying them.
-
Find healthy ways to
cope with stress.
Stress may trigger an attack
of acute angle-closure
glaucoma. Relaxation
techniques may be helpful in
dealing with stress.
-
Wear proper eye
protection. Eye
trauma can result in
increased eye pressure. Wear
safety glasses or goggles
when you play sports, use
tools or machinery, or work
with chemicals.
