Download JORNAL DO BRASIL (*) March 23, 2012 Section: Country / Open

JORNAL DO BRASIL (*)
March 23, 2012
Section:
Country / Open Society
Myths about Glaucoma
Remo Susanna Jr.
The study on Glaucoma has already travelled a long way. Its development has
occurred in all corners of the world and the availability of resources, scientific
interchange and creativity have never been so great as in the recent years.
Today the study of Glaucoma is a universal science. The high number of congresses
held all around the world allows that colleagues from different origins and with different
perceptions about the disease share their experiences, knowledge and creativity to our
own benefit and, mainly, to that of our patients. However, many deep-rooted myths still
existing among the people make the diagnostic and treatment of the disease difficult,
perpetuating its position as the world’s leading cause of irreversible blindness.
The most common myths about glaucoma
Myth 1: All glaucoma patients have high intraocular pressure
It was believed that individuals with intraocular pressures above 21 mmHg had
glaucoma, and that intraocular pressures below 21 mmHg were normal. In fact, there
are people with intraocular pressure below 21 who have glaucoma (normal tension
glaucoma) and others with intraocular pressure above 21 (ocular hypertension) who do
not have glaucoma.
What determines the presence or not of glaucoma is the aspect of the optic nerve. So,
always ask your ophthalmologist how the pressure of your eye and optic nerve are.
Myth 2: I can see very well so I do not have glaucoma
Most types of glaucoma will only show symptoms in the most advanced stages of the
disease. Once lost, vision cannot be recovered. The impairment in one eye is
compensated by the other eye and vice-versa, masking the vision loss. In addition,
even when the impairment is already advanced, the brain complements the missing
image with surrounding images, making the vision loss imperceptible for the individual.
(*) Jornal do Brasil is one of Brazil’s most traditional newspapers and the first to have an online
edition.
Myth 3: You can test your peripheral vision to know whether you have glaucoma
or not
The most common types of glaucoma damage peripheral vision. Many patients think
that they can evaluate this loss by covering one eye and testing their field of vision.
Patients frequently state this in the ophthalmologists’ offices. In fact, the field initially
lost is not the temporal field (right temple side for the right eye and left temple side for
the left eye) but the nasal field (beside the nose, which in most cases is hidden by the
individual’s own nose; left side for the right eye and right side for the left eye. Based on
this test erroneously made, the patient thinks he/she is in perfect conditions. In fact, it
is impossible to test the peripheral vision, especially on the nasal side without the
proper equipment and technique only available in ophthalmologists’ offices.
Myth 4: Lifestyle does not influence glaucoma
Aerobic exercises like swimming, running and fast walking for at least 30 minutes 3
times a week can reduce intraocular pressure by up to 20%. Glaucoma patients
should avoid being upside down – like in certain Yoga exercises – which can increase
intraocular pressure by approximately 200% (twice the intraocular pressure). Smoking
can also increase intraocular pressure. Although marijuana lowers intraocular
pressure, its effect is quite short-lived and pressure reduction insufficient.
Myth 5: Exams for detection of glaucoma are tiring
Not all of them. The one patients complain more about is the visual field test.
There are three basic glaucoma exams, each with its variances
1. Ophthalmoscopic exam, in which the doctor examines the eye funds giving
special care to the optic nerve. This exam is often accompanied by a
stereoscopic photography of the nerve or computerized images to document
and best evaluate the optic nerve. Only through documentation of the optic
nerve by means of these complementary exams the ophthalmologist will be
able to detect structural changes to it, that is, detect the advance of the disease.
2. Measurement of the intraocular pressure which, due to its fluctuation and
peaks, should be evaluated by means of a water load test, or minicurve or 24hour tensional curve. It can also be evaluated by means of measurements in
different times and on different days.
3. Visual Field Test (perimetry), which is the test patients like least; it consists in a
projection of light with different intensities to detect the loss of peripheral vision
and, when present, central vision as well.
Myth 6: To have the intraocular pressure measured once in the
ophthalmologist’s office is sufficient
In fact intraocular pressure may vary more than 10 mmHg in 24 hours. That is why it is
necessary to measure it several times and/or do the water load test in order to detect
the pressure peak, which is considered one of the most important factors for the
progress of the disease. These measurements are recommended for suspect
glaucoma patients and glaucoma patients, and do not need to be routinely done in
individuals considered normal after a careful evaluation of the optic nerve.
Myth 7: With the treatment my intraocular pressure is normal
This is a dangerous myth. The expression ‘normal pressure’ refers to a statistic value
found in the population and not for control of the disease. So, “normal intraocular
pressure” may eventually lead to blindness. There is not a magic pressure level for all
patients. Some patients require 10 mmHg pressures while others with higher
pressures experience no damage to their visual function. This is the concept of target
pressure. It is determined on an individual basis by ophthalmologists based on a
series of factors like age, life expectation, degree of the glaucoma injury, disease
progression speed, etc.
Myth 8: Glaucoma always leads to blindness
Completely wrong. According to The Glaucoma Foundation, at least 90% of the
glaucoma cases would not lead to blindness if adequately diagnosed and treated.
Unfortunately, less than 50% of the individuals with glaucoma are diagnosed. Very
often, and for different reasons, treatment is not efficient. So, if glaucoma is timely
diagnosed, treatment is monitored through measurement of the visual field, optic nerve
exams and good intraocular pressure charts, blindness could be prevented in the great
majority of people, if not in almost all of them.
Myth 9: There are few options of glaucoma treatment
There is a great variety of glaucoma treatments available. Medical treatment has
progressed a lot with very powerful drugs or drug combinations to reduce intraocular
pressure and control its peaks. The use of laser and numerous modern techniques
have increased surgical success and greatly reduced complications.
Glaucoma remains as the world’s major cause of irreversible blindness and its
reputation is sinister because most times it hits both eyes of the individual; its
symptoms only appear in the advanced stages of the disease; it is frequent in
glaucoma patients’ direct blood relatives, thus binding several family members. With
the help from institutions like ABRAG, greater knowledge about the disease by people
in general and ongoing progress in diagnostic and treatment, I believe the sinister
reputation of this disease is about to end.