It takes no longer than a coffee break – but this simple and painless test can
save you from going blind.
An ophthalmologist has merely to put some
anesthetic drops onto your eyes, wait a few minutes and then, for a second or
two, hold a tonometer device against the transparent cornea coating your
eyeball.
The intraocular pressure in each eye is quickly measured, and if
glaucoma is suspected, additional tests are conducted to confirm the
diagnosis.
Yet many Israelis over 50 (or younger if they have a family
history of the disease) avoid going for annual testing, and as a result their
optic nerves suffer irreversible damage.
Between 80,000 to 100,000
Israelis suffer from some kind or some stage of glaucoma; there are between
5,000 and 7,000 new cases a year. Of the 30,000 to 40,000 blind people here,
nearly 5,000 lost their sight to glaucoma.
A clear liquid, called
“aqueous humor,” that is constantly produced behind the iris (colored part of
the eye) fills the front part of the eye. It drains out of the eye through
channels in an area called the anterior chamber angle (“the angle” for short).
If the exit point is clogged and the intraocular pressure builds up slowly over
time, glaucoma results.
The intraocular fluid is vital for the health of
the eye, as it feeds tissues and prevents the eyeball from collapsing like a
deflated beach ball. The eye’s structure includes an amazing maze of drainage
channels known collectively as the trabecula.
Normally, pressure inside
the eye stays constant because fluid production and outflow maintain a
balance.
When tonometry testing diagnoses the usually painless
degenerative eye disease, it doesn’t necessarily mean that lost vision can be
recovered, but additional damage to the optic nerve – which transmits
information from the eye to the brain – can be prevented with regular checkups,
special drops and laser treatment (called iridotomy) or eye surgery. Lowering
eye pressure by at least 30 percent can keep the condition from progressing in
some patients.
Because there is such minimal awareness of glaucoma – many
general practitioners don’t even routinely recommend to their middleaged and
elderly patients that they go for annual eye exams – Glaucoma Awareness Week was
held recently in Israel and the world.
There are four main types of the
disease: open-angle (chronic) glaucoma; angle-closure (acute) glaucoma;
congenital; and secondary.
Open-angle, which tends to run in families and
comprises about 95 percent of cases, is referred to as “primary,” as it does not
result from other diseases.
In open-angle glaucoma, drainage fails to
keep pace with the output of new aqueous humor.
Pressure on the optic
nerve builds as the level of fluid rises. Damaged optic nerve fibers die off one
by one, and the nerve bundle begins to resemble a frayed extension cord, no
longer able to transmit complete signals from the eye to the brain. This process
takes place so gradually that vision loss may be imperceptible until
irreversible vision loss has occurred.
Angle-closure glaucoma is an
emergency in which the drainage of the aqueous humor is suddenly blocked. Unlike
the most common kind, the problem causes severe and sudden pain. A sufferer must
go for immediate medical care, which is likely to involve eye drops or other
medications.
Congenital glaucoma occurs in infants and often runs in
families, but is rare. Secondary glaucoma may result from taking steroids or
other drugs, trauma, certain systemic diseases or other eye
diseases.
ALMOST EVERY hospital in Israel has a glaucoma clinic, says Dr.
Benzion Silverstone, head of the glaucoma unit at Jerusalem’s Sha’are Zedek
Medical Center. Due to the aging of the population, the number of patients
diagnosed with glaucoma is constantly growing – but would increase even more if
the general public were more aware of the disease, he added during an interview
with The Jerusalem Post.
While excessive pressure is almost always the
cause of the disease, there is a minority of cases in which patients have normal
intraocular pressure but still get glaucoma.
Ophthalmologists still don’t
understand why, Silverstone said.
The waiting room outside the hospital’s
outpatient eye clinics is packed. “We have four glaucoma specialists in the
unit, but it’s still hard to keep up,” he admitted. During our interview, so
many people wanted to see him or ask questions that he had to lock the doors
from both ends to be able to speak uninterrupted.
“Today, our unit is the
largest in the city. We see 60 to 100 patients a week,” he explained.
The
ophthalmologist, who was born in Mexico, studied general medicine there and then
came on aliya. His internship was at Sha’are Zedek, where he has worked for 35
years. His wife is from South Africa, where he did two years of advanced studies
at the University of the Witwatersrand. As blacks have a high rate of glaucoma,
he learned a lot about the disease there. One of the world’s top experts in
glaucoma was at the South African university. “I preferred ophthalmology because
I liked doing delicate surgery,” he said.
Your risk is higher if you have
a parent or grandparent with open angle glaucoma; you are well advised to go by
age 40 for screening in this case.
There is a clear ethnic connection to
the prevalence of glaucoma, with those of African descent being three times more
likely to contract the disease. Many people of East Asian descent are at higher
risk of developing angle-closure glaucoma due to shallower anterior chamber
depths, while women are three times more likely than men to develop acute angle
closure glaucoma because their anterior chambers are more shallow.
Even
dogs and other animals can contract glaucoma, and undergo treatment very similar
to that of humans.
“We perform between 50 and 60 operations a year on
glaucoma patients, some also with cataracts.
When YAG lasers are used, it
takes only a few minutes to open up the ducts. We have only about two operations
a year on infants with the congenital type, which affects fewer than one baby
out of 10,000,” Silverstone said.
When asked whether the excessive fluid
could be “vacuumed” out of the eye, the ophthalmologist smiled and noted there’s
an unusual form of the disease called pigmentary glaucoma, for which German
experts indeed use a tiny vacuum cleaner to suck out the colored fluid, but
added that this technique cannot be used for any other kind of
glaucoma.
Ideal intraocular pressure is between 12 and 22 millimeters of
mercury. “High pressure is bad, but low pressure is also not good,” he said.
Optic nerve damage that results from inadequate fluid pressure in the eye is
called low-tension glaucoma.
Silverstone introduced at his unit new
surgical techniques, such as deep sclerectomy, and no longer performs the
standard operation, called trabeculectomy, that was first developed in the
1960s. “The new techniques involve fewer complications such as bleeding or
infections,” he explained. A number of new, experimental techniques to treat
glaucoma, such as the implantation of tiny tubes in the angle to facilitate
drainage, are being developed, and this should eventually bring good news to
patients.
Most glaucoma patients can be stabilized with eyedrops, but not
all the medications are in the basket of health services, said
Silverstone.
“The new ones not provided yet by the health funds are those
without the preservative known as BAK.
These offer better results than
those with preservatives, which can cause allergies in patients, but there is
only one type of eye drops without BAK in the basket.”
Glaucoma could be
a natural result of aging, he continued, but there has still been no
breakthrough in the understanding of the reasons for the disease. “Some genes
are thought to be involved because it tends to run in families. But the
researcher who discovers all the causes would surely receive the Nobel
Prize.”
The majority of patients who have open-angle glaucoma receive a
variety of eye drops, not just one type, to control the pressure. The latest
drops cause fewer side effects than the previous generation of
medications.
Medication not in the form of eye drops can be administered
orally or through a vein.
SHA’ARE ZEDEK has the only mobile unit in the
country for the diagnosis of glaucoma, says Dr. Amos Mazover, who runs it
in the Jerusalem area. It was established by the late Sam Rothberg, a major
leader and philanthropist of the American Jewish community who lived in Peoria,
Illinois, and died six years ago at the age of 94. He established two such
outreach centers – one at the Goldschleger Eye Institute at Sheba Medical Center
and the other at Sha’are Zedek, but the mobile unit at Sheba closed a few years
ago, Mazover said. Rothberg’s daughter, who was interested in the product,
continued to fund Sha’are Zedek’s mobile unit through the Jerusalem
Foundation.
Mazover noted that even though family physicians routine ask
older patients to undergo a stool test to detect colorectal cancer, many do not
remind them to go for an annual eye pressure test.
He drives to
government and private offices, factories, community centers, old age homes and
hospitals and with a nurse and a volunteer provides free tonometry tests. The
mobile unit is a van containing equipment that is unloaded to perform eye tests.
It roams not only through the capital but also as far as Beit Shemesh, Ma’ale
Adumim (and once reached Modi’in).
“One can go to one’s eye doctor and
take a test by paying the NIS 22 copayment; the problem is that so few people do
this on an annual basis. So we come to them. We check for intraocular pressure
in a few minutes, but we have also detected cataracts and even found signs of a
brain tumor,” Mazover said. “As glaucoma rarely causes pain, people don’t bother
to go to check for it.”
Join Jerusalem Post Premium Plus now for just $5 and upgrade your experience with an ads-free website and exclusive content. Click here>>