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Who Should Be Examined for
Glaucoma?
How Common is Glaucoma?
Glaucoma is a common group of eye disorders, and the second
most common
cause of blindness worldwide. By the year 2000, it is
estimated that as many as 67 million individuals will
have glaucoma. Millions more have high intraocular pressure,
which is the leading risk factor for glaucoma. Such individuals
are at higher risk for developing this condition.
Are There Racial Differences?
In addition, there appear to be substantial differences
in the racial susceptibility to glaucoma. In particular,
it is the most common cause of blindness among black (Africanorigin)
and probably also among Japanese individuals. Between
one and two percent of white individuals who are 40 years
of age or older have glaucoma. However, between five and
six percent of blacks (Africanorigin) in the same age
group have glaucoma.
Who Should Be Examined for
Glaucoma? |
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| In the
age group of 70 years or older, at least one out
of ten black persons has glaucoma. In the United
States, for example, African-Americans comprise
about 10 percent of the entire population. However,
it is estimated that they comprise 25% of those
affected with glaucoma. Studies show that a much
higher proportion of glaucoma patients are blind
in Africa and the Caribbean than in Europe. Glaucoma
develops at an earlier age in black individuals
and is often more difficult to treat satisfactorily.
We do not know for sure how often glaucoma occurs
among other ethnic groups. |
Figure 1. By the year 2000 it is estimated that
as many as 67 million individuals worldwide will
have glaucoma. Although certain racial groups are
more susceptible, glaucoma can occur in any individual.
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Figure 2. The leading risk factor for glaucoma
is believed to be high intraocular pressure. |
What
Are the Risk Factors for Developing Glaucoma?
Currently, there is no method to prevent glaucoma.
Although it is possible that lifestyle considerations
such as diet and stress may affect the development
of glaucoma, there is not enough information on
this subject for your eye doctor to make specific
recommendations. It is known, however, that the
risk of developing glaucoma is higher in certain
people.
High Intraocular Pressure
The leading risk factor for glaucoma is believed
to be high intraocular pressure. In many |
patients, intraocular pressure appears to directly contribute
to optic nerve damage. For this reason, reduction of intraocular
pressure reduces progressive damage in many individuals.
Risk Factors for Glaucoma
- High intraocular pressure
- African-origin
- Old age
- Family history of glaucoma
- Nearsightedness
- Medical diseases
Diabetes
High blood pressure
Migraine headaches
Old Age
Glaucoma is far more likely to develop in older individuals
than in younger ones. For example, the chance of having
glaucoma is two to eight times higher for an 80-year-old
than for a 40-year-old. However, black African individuals
tend to develop glaucoma at a much younger age. It would
not be surprising for a 30-year-old black person to develop
glaucoma, whereas this would be unusual for a 30-year-old
white person.
Nearsightedness
Nearsighted (myopic) individuals are at greater risk,
and more likely to develop glaucoma.
Other Risk Factors People with certain medical
diseases, particularly diabetes,
may also be more likely to develop glaucoma. High blood
pressure (systemic hypertension) and migraine headaches
may also place individuals at risk.
Whether all types of glaucoma can be inherited is not
known. However the chance of developing glaucoma is much
higher if someone in the family has it. This is particularly
true if a first degree relative such as a parent, a brother,
or a sister has this disorder. |
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A
thorough examination for glaucoma must include an
examination of the optic nerve.
Glaucoma – the Silent Disease
Glaucoma is dangerous because you may not be aware
that you are losing your vision. By the time you
notice a change in your eyesight, the glaucoma may
be at a very advanced stage, and
difficult to treat effectively. Unlike cataracts,
in which the vision becomes blurred, the central
vision is typically clear and unaffected until the
late stages. This may be a major reason why approximately
half of the individuals with glaucoma do not even
know that they have it. Any vision lost from glaucoma
is for the most part permanent. Although treatment
cannot restore the lost sight, successful treatment
can prevent further vision loss. Early detection
is therefore the key to preventing progressive loss
of sight from this disease.
Examination for Glaucoma
Unfortunately, many people are not thoroughly examined
for glaucoma until a significant amount of vision
is already irreversibly lost. Besides being interviewed
by your eye doctor to determine whether you may
be at risk, the eye pressure should be measured.
In addition, a thorough examination for glaucoma
must include an examination of the optic nerve.
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Figure 3. Besides being interviewed by your eye
doctor to determine whether you might be at risk,
your eye pressure should be measured.
Figure 4. A thorough examination for glaucoma must
include an examination of the optic nerve. |
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Early detection is therefore
the key to preventing loss of sight from glaucoma.
After your examination, a visual field test, which
measures the peripheral vision, should be performed if
there is an indication of possible glaucoma or to best
exclude it being present. How Often Should People
Be Tested for Glaucoma?
Everyone who is at risk of developing glaucoma should
have an eye examination at regular intervals. Individuals
at greatest risk should be examined
more often. Such as elderly individuals and those with
a family history of glaucoma. In general it is recommended
that all persons 40 years old or older be examined for
glaucoma at least once every two years. Individuals who
are 60 years of age or older, and those with other important
risk factors, such as diabetes or a family history of
glaucoma, should be examined for glaucoma at
more frequent intervals, perhaps once yearly.
How Often Should an Individual Be Examined to Detect
Glaucoma?
- Between age 40 and 60 At least once every two years
- Older than age 60 Once a year
- Other risk factors (e.g., diabetes, high blood pressure,
family history) Once a year after age 40
- Black African (between age 30 and 40 Once every
two years
- Black African
(older than age 40) Once a year
Examination by your eye doctor on a regular basis will
allow glaucoma to be detected and treated early. Glaucoma
treatment is more effective when it is begun at an early
stage of the disease. Loss of vision from glaucoma is
preventable through early detection and treatment.
Authors: Roy Wilson, M.D. Robert N. Weinreb, M.D.
Glaucoma, A Patient Newsletter
is supported by unrestricted grant. Specific commercial
products are not endorsed. You should address questions
about your own eye condition to your eye doctor. General
questions that may benefit other individuals with glaucoma
can be sent to:
Glaucoma,
A Patient Newsletter
P.O. Box 12125
La Jolla, CA 92039, USA
Editor: R.N. Weinreb, M.D.
La Jolla, California, USA
Editorial Advisory
Board Europe
A. Alm, M.D., Sweden
A. Anton, M.D., Spain
A. Bron, M.D., France
E. Greve, M.D., Netherlands
A. Hommer, M.D., Austria
G. Krieglstein, M.D., Germany
C. Migdal, M.D., United Kingdom
C. Traverso, M.D., Italy |
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