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Glaucoma
Glaucoma: An Introduction
What
causes Glaucoma?
What
are the types of Glaucoma?
What
are the symptoms of Glaucoma?
How
is Glaucoma diagnosed?
How
is Glaucoma treated?
How
should I use my Glaucoma eye drops?
How
often will I need to be examined?
Glaucoma: A family matter.
Blanco Eye Associates: Our
Philosophy
Glaucoma: An
Introduction
Glaucoma is a major health problem and it is estimated
that 3 million people in the United States have this
disease, and that as many as half of them may be unaware
of the problem. Every year over 100,000 Americans
develop glaucoma. In the United States glaucoma is the
second most common cause of legal blindness.
Approximately 100,000 Americans are legally blind from
glaucoma and many more have visual impairment. Glaucoma
is the leading cause of preventable blindness. Even
though there is no cure for glaucoma, with proper
treatment, blindness can be prevented in 90% of the
cases.
What causes glaucoma?
Glaucoma, for reasons that are not completely
understood, is a disease that causes damage to the eye's
optic nerve. It typically occurs when the normal fluid
pressure inside the eyes rises. I like to make the
analogy that your eye is filled with fluid (the aqueous
humor which fills the anterior chamber) like a tire is
filled with air. The more air in the tire, the higher
the pressure will be. In the case of the eye, there are
glands(in the ciliary body) that secrete fluid into the
eye and there are outflow channels(Trabecular meshwork,
Schlemm’s canal, Episceral veins, and Aqueous veins)
where the fluid drains out of the eye. In glaucoma, the
outflow channels don't work as well so fluid is coming
in faster than it is going out; consequently the
pressure of the eye gradually builds. The pressure, we
think, can build to a level where it affects the
circulation of blood to the optic nerve. If the optic
nerve does not get enough blood nerve fibers die, and
over a period of time, vision loss can occur.
Another theory is that the
pressure of the eye simply compresses the optic nerve
fibers and eventually destroys them. The optic nerve
fibers that typically die first in glaucoma are the ones
responsible for side vision. Since a person's side
vision is so wide, oftentimes they are unaware of side
vision changes until the damage from glaucoma is already
occurring.
Although glaucoma typically occurs from high-pressure,
sometimes it can occur when the pressure of the eye is
in a normal range or even lower than normal.
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What
are the different types of glaucoma?
1. Open angle glaucoma, sometimes referred to as
"primary" or "chronic" glaucoma is the most common type.
The pressure of the eye gradually builds over time
without any symptoms during the early stages.
2. Closed angle glaucoma, sometimes referred to
as "acute" or "narrow angle" glaucoma, causes a rapid
buildup of pressure in the eye, resulting in severe eye
pain, nausea, blurred vision, and the appearance of
rainbow colored halos around lights.
3. Normal tension glaucoma, sometimes referred to
as "low tension" glaucoma, causes damage to the optic
nerve in people where the eye pressure is in either an
average range or even lower than average range. This can
sometimes occur when there is compromised blood flow to
the optic nerve due to carotid or cardiovascular
disease. Sleep apnea is another condition that may be a
predisposing factor.
4. Congenital glaucoma occurs in children born
with a defect in the drainage system of the eye.
Generally these children have obvious symptoms such as
cloudy eyes, sensitivity to light, and excessive
tearing. If treatment (typically surgery) is done
promptly, these children have an excellent chance of
having good vision.
5. Secondary glaucomas can develop as
complications of other medical conditions. They are
sometimes associated with eye surgery, advanced
cataracts, eye injuries, certain eye tumors, excessive
pigment or pseudoexfoliation in the eyes, corticosteroid
drug use, or in association with diabetes.
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What are the symptoms of
glaucoma?
Unless a person has "closed angle glaucoma" there are no
symptoms in the early stages, which is why glaucoma is
often called the "sneak thief of sight"; vision stays
normal, and there is no pain. However, as the disease
progresses a person may notice his or her side vision
gradually failing. Objects in front may still be seen
clearly but objects to the side may be missed.
Eventually "tunnel vision" may occur, and at the end
stage of the disease little or no vision may remain.
Even though sight lost to glaucoma cannot be restored,
glaucoma can usually be controlled 90% of the time if
detected early.
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How is glaucoma diagnosed?
It has been said that diagnosing glaucoma can sometimes
be more complicated than treating it. Glaucoma is
detected through a comprehensive eye examination that
includes:
1. Applanation Tonometry This is an instrument
that measures the pressure inside the eye. This is the
most accurate way to measure the pressure by making
slight contact with the eye. It is done using numbing
drops.
2. Pachymetry This is an instrument that measures
the thickness of your eye. Research indicates that
individuals with thin eyes can't withstand the pressure
in the eye as well as thicker eyes. Also, a modification
of the pressure determined by tonometry may need to be
done related to the thickness of the eye.
3. Visual field test This test measures your
peripheral vision which is the first area of vision loss
in glaucoma.
4. Optical Coherence Tomography (OCT) This is a
technologically advanced scanning of the optic nerve
based on complex analysis of the reflections of light
from the optic nerve and the nerve fiber layer to
determine whether damage has occurred. OCT has greatly
benefited both the diagnosis and management of glaucoma
patients.
5. Optic nerve photography Since the appearance
of the optic nerve changes during the course of this
disease, having a photograph of the optic nerve for
comparison purposes is valuable.
All of the above tests, excluding pachymetry, are also
done on a routine basis during the management of the
disease.
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How is glaucoma treated?
Immediate treatment for glaucoma by lowering the
pressure of the eye at the earliest possible stage can
delay the progression of the disease and that's why
early diagnosis is so important. Intermediate and
advanced glaucoma is more difficult to treat resulting
in a higher percentage of patients losing their vision.
1. Eye drops Glaucoma treatment most typically
involves using eye drops. Some medications cause the eye
to make less fluid and others lower the pressure by
helping fluid drain from the eye.
2. Laser treatments or Surgery When eye drops
fail to lower the pressure or the patient is
noncompliant using their drops, surgery is the next
option. Like eye drops, these procedures can be valuable
in the improvement of fluid outflow or can be used to
reduce the production of fluid. Laser treatments or
surgery carry a greater risk of complications, including
the development of cataracts, and repeat procedures may
be required.
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How should I use my glaucoma eye drops?
If drops have been prescribed for treating your glaucoma
you need to use them properly. Proper use of your
glaucoma medication can improve the medicine’s
effectiveness and reduce your risk of side effects. To
properly apply your eye drops 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 on your lower eyelid; this
forms a pocket.
• Place a drop into the lower eyelid pocket.
• Put pressure where your eyelids meet next to your nose
using the thumb and index finger. You will feel a little
bump on each side of the nose where the eyelids meet.
This is called "punctual occlusion". Try to keep your
eyes closed for 2 minutes after you place the drops in
your eyes.
• If you are using more than one eye drop, be sure to
wait at least five minutes before applying the second
eye drop.
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How often will I need to be examined?
Glaucoma, like other chronic diseases, requires an
establishment of a strong physician-patient
relationship, ongoing therapeutic regimen, and regular
office visits. After the initial examination and
diagnosis, the average patient needs to be seen 3-4
times yearly. The pressure of the eye will be checked
regularly during the year, visual field studies and OCT
testing will be done at least one time per year.
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Glaucoma: A Family Matter
Open angle glaucoma, which accounts for 90% of glaucoma
cases, can be hereditary in nature. According to a study
by Johns Hopkins School of Medicine, blood relatives of
people with glaucoma oftentimes don't realize they are
at greater risk for developing this disease. Family
members of those with glaucoma have a 10 times greater
risk than the normal population. Johns Hopkins
researchers discovered that the lack of knowledge about
glaucoma risk factors, including heredity, stems from
lack of patient education. Eye doctors, they say, have
to do more than ask about family history. They need to
say directly, "If you have glaucoma, your siblings and
your children may be at risk, and they need a
comprehensive eye examination”.
The Johns Hopkins study is important because glaucoma is
largely without obvious symptoms until the disease is
well advanced. When glaucoma is caught early, eye drops,
laser treatment, or surgery can delay its progression by
lowering the elevated pressure in the eye that
ultimately damages the optic nerve.
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Blanco Eye Associates:
Our Philosophy:
It has been said that to be successful at anything, two
essential elements are required, intention and
attention. We take our work very seriously and it is our
intention to provide the highest quality of care
in glaucoma management. I personally have made a
commitment to give appropriate attention to stay
abreast of every new development in the field of
glaucoma care. This requires constant reading, seminars,
and a system of e-mail alerts regarding new research and
breaking news. It also requires a commitment to equip my
office with the best/newest technology available, and to
sincerely care about the visual well -being of our
patients. We have made that commitment!
I sincerely appreciate the opportunity to be your
doctor.
Thank you,
Jeffrey Blanco, OD
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