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You
may not notice peripheral loss of vision
as central vision is maintained till
end stage of Glaucoma.
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Glaucoma is the second most common cause of blindness.
Patients
may not get any symptoms like pain in the eye or
loss of vision and may lead to permanent loss of
vision.
Glaucoma
can be detected by checking the eye pressure, examination
of the Optic nerve and computerized visual field
testing with the latest Humphrey Perimeter from
Zeiss.
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Glaucoma is an eye disorder in
which the major risk factor is increased pressure within
the eye. Glaucoma is a disease that damages the optic nerve
and causes loss of vision. Unfortunately, there are no discernible
symptoms in the early stages of the disease, and glaucoma-induced
damage to your eye is irreversible.
Globally,
glaucoma is the second most common cause
of blindness after cataract. It accounts
for 7-8 million bilaterally blind people.
In India, it is responsible for 8-12%
of blindness. Half of the people with
glaucoma are usually unaware of it until
serious loss of vision has occurred.
The good news is that there are simple
diagnostic tests, which, if performed
regularly, can detect the disease in
its early stages while serious vision
loss is still preventable.
Types
of Glaucoma
There are many types of glaucoma.
The four most common varieties include:
Chronic
Open-Angle Glaucoma
By far the most common type, open-angle glaucoma can steal vision so quietly
that you may be unaware of any problem until your optic nerve is badly damaged.
Blockages in your eye’s natural drainage system build up over time,
often as a result of the natural aging process. The first symptom of open-angle
glaucoma may be vision that is blurred at the edges, but by this time the
optic nerve is irreparably damaged.
Acute
Angle-Closure Glaucoma
This type of glaucoma occurs suddenly when the iris presses against the drainage
area and closes it off. Fluid backs up and pressure rises rapidly. Symptoms
of angle-closure glaucoma include blurred vision, severe pain, nausea, vomiting
and the appearance of rainbow halos around lights. Immediate medical attention
is essential as angle-closure glaucoma can lead to blindness within days.
Secondary
Glaucoma
Channels within the eye can become blocked for reasons such as infection,
injury, diabetes, certain drugs, hemorrhage or tumors. This condition, called
secondary glaucoma, may exhibit symptoms similar to angle-closure glaucoma.
Secondary glaucoma requires prompt medical attention to prevent serious vision
loss.
Congenital
Glaucoma
In rare cases,
the drainage system within the eye is
poorly formed at birth. The natural elasticity
of the infant eye may allow rising pressure
to be accommodated for a while, but eventually
a problem develops. The infant may be
sensitive to light or may tear excessively;
the front of the eye may appear cloudy
or “foggy.”
Signs & Symptoms,
What are the Symptoms?
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 the disease worsens,
the field of vision narrows and blindness results.

Normal Vision
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Same scene as viewed by a person with glaucoma
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What
Causes Glaucoma?
Normally, a clear fluid called the aqueous humour flows through your inner
eye, bathing it constantly and nourishing the surrounding tissue. With glaucoma,
the fluid drains too slowly and builds up causing pressure inside the eye
to rise. The pressure, in turn, affects the optic nerve, which is like an
electronic cable carrying messages to your brain – messages that normally
result in sharp, clear vision. If the entire nerve is destroyed, blindness
is the result.
Are
there other risk factors?
Race: Narrow angle glaucoma is more common in Asians. African-Americans and
older Hispanics are four or five times more likely than Caucasians to develop
open angle glaucoma, and are six times more likely to suffer blindness as
a result of glaucoma.
Risk factors
in addition to age and race include:
-
high
blood pressure
-
diabetes
-
injury
to the eye
-
family
history of glaucoma.
-
Open
angle glaucoma is associated with myopia (shortsightedness),
while narrow angle glaucoma is associated with hyperopia
(far sightedness)
People with two or more
risk factors are urged to have a complete eye examination,
including dilation, every year.
Early
detection is the key
It is estimated that nearly half of the patients who have glaucoma are unaware
of it. That is why regular examinations- even when you have no symptoms-
are so important. However, elevated eye pressure is not always a sign of
glaucoma. Approximately one-third of those who develop glaucoma do not have
elevated eye pressure.
A far better precaution
is a professional eye exam which includes pupil dilation
and inner eye examination by ophthalmoscope, as performed
at DLEI. If you are over 40, we recommend you have
your eyes professionally checked for glaucoma every
year.
How
is glaucoma detected?
Glaucoma is detected through
a Comprehensive Eye Exam, which may include:
-
Measuring
your intraocular pressure (tonometry)
-
Inspecting
the drainage angle of your eye (gonioscopy)
-
Evaluating
whether or not there is any optic nerve damage (ophthalmoscopy)
-
Testing
the peripheral vision of each eye (visual field testing
or perimetry)
Photography of the optic
nerve or other computerized imaging may be recommended.
Some of these tests will not be necessary for everyone.
Treatment
Generally, damage
caused by glaucoma cannot be reversed. Glaucoma
treatments include medicines – oral tablets
and eyedrops, LASER treatment, 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.
Surgical
and Non-Surgical Glaucoma Treatments
If you are found to have
glaucoma, you will probably be treated with medication
in the form of eye drops or pills. The medication works
to reduce pressure by decreasing the amount of fluid
entering your eye or assisting fluid flow through your
eye.
In some cases, your medication may produce side effects such as blurred vision
or occasional headaches; the eye drops may redden your eye or sting, and
your night vision may be reduced. Most of these simple side effects lessen
over time; however if you experience more serious side effects such as drowsiness,
tingling of fingers and toes, loss of appetite or changes in pulse, heart
rate and breathing, you should notify your doctor.
In cases where medication
cannot be tolerated or loses its effectiveness over
time, surgery is necessary to prevent further vision
loss.
Self-Care
Controlling
glaucoma is up to you
As we have said, glaucoma- often called the "sneak thief" of sight-
is not normally heralded by obvious symptoms. To safe-guard vision, anyone
over 40 should undergo a comprehensive eye examination every year. This also
applies if other risk factors are present such as high blood pressure, diabetes
or a family history of glaucoma.
If you have been diagnosed
with glaucoma, you must follow instructions meticulously
with regard to your medication. It must become a central
part of your daily routine if it is to be effective!
You should never stop taking your medication without
talking to your ophthalmologist or optometrist. Also,
if you are seeing other physicians for any reason,
tell them about your eye medication.
Finally, because the effects
of glaucoma may worsen (or improve) without your being
aware of the change, follow your eye doctor's recommendations
on regular check-ups to monitor your progress.
Glaucoma
and high blood pressure
Glaucoma is not generally
related to high blood pressure, however, any patient
on high blood pressure medication should inform their
ophthalmologist and family doctor of all medications
they are currently taking. Certain drugs taken for
glaucoma can interact with those taken for other conditions.
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