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Glaucoma damages the eye's optic nerve. It usually happens when the fluid
pressure inside the eyes slowly rises.
Often there are no symptoms at first, but a comprehensive eye exam can
detect it.
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| What is the optic nerve? |
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At the front of the eye, there is a small space called the anterior chamber.
Clear fluid flows in and out of the chamber to bathe and nourish nearby
tissues.
In glaucoma, the fluid drains too slowly out of the eye. As the fluid builds
up,
the pressure inside the eye rises. Unless this pressure is controlled,
it may
cause damage to the optic nerve and other parts of the eye and loss of
vision.
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| What is Eye Pressure? |
Eye pressure is regulated by the aqueous fluid, which is produced by the
ciliary body.
Normal eye pressure is 10 to 21 millimeters of mercury, or mmHg.
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| What is the aqueous humour? |
Aqueous humour is optically clear, slightly alkaline liquid
that occupies the anterior and posterior chambers of the eye
(the space in front of the iris and lens and the ringlike space encircling
the lens).
It provides these nutrients (as well as oxygen) to eye tissues
that lack a direct blood supply (such as the lens) and also removes their
waste products.
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| Types of diseases |
Open-angle glaucoma is the most common form.
Some people have other types of the disease.
1. Low-tension or normal-tension glaucoma
Optic nerve damage and narrowed side vision occur in people with normal
eye pressure.
Lowering eye pressure at least 30 percent through medicines slows the disease
in some people.
Glaucoma may worsen in others despite low pressures.
2. Angle-closure glaucoma
The fluid at the front of the eye cannot reach the angle and leave the
eye.
The angle gets blocked by part of the iris. People with this type of glaucoma
have a sudden increase in eye pressure. Symptoms include severe pain and
nauseas,
as well as redness of the eye and blurred vision.
If you have these symptoms, you need to seek treatment immediately.
3. Congenital glaucoma
Children are born with a defect in the angle of the eye that slows the
normal drainage of fluid.
These children usually have obvious symptoms, such as cloudy eyes, sensitivity
to light, and excessive tearing.
Conventional surgery typically is the suggested treatment, because medicines
may have unknown effects
in infants and be difficult to administer. Surgery is safe and effective.
If surgery is done promptly, these children usually have an excellent chance
of having good vision.
4. Secondary glaucomas
These can develop as complications of other medical conditions.
These types of glaucomas are sometimes associated with eye surgery or advanced
cataracts,
eye injuries, certain eye tumors, or uveitis (eye inflammation).
Pigmentary glaucoma occurs when pigment from the iris flakes off
and blocks the meshwork, slowing fluid drainage.
A severe form, called neovascular glaucoma, is linked to diabetes.
Corticosteroid drugs used to treat eye inflammations and other diseases
can trigger glaucoma in some people.
Treatment includes medicines, laser surgery, or conventional surgery.
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| Does increased eye pressure mean that I have glaucoma? |
Not necessarily. Increased eye pressure means you are at risk for glaucoma,
but does not mean you have the disease.
A person has glaucoma only if the optic nerve is damaged.
If you have increased eye pressure but no damage to the optic nerve, you
do not have glaucoma.
However, you are at risk. Follow the advice of an ophthalmologist.
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| Can I develop glaucoma if I have increased eye pressure? |
Not necessarily. Not every person with increased eye pressure will develop
glaucoma.
Some people can tolerate higher eye pressure better than others.
Also, a certain level of eye pressure may be high for one person but normal
for another.
Whether you develop glaucoma depends on the level of pressure your optic
nerve
can tolerate without being damaged. This level is different for each person.
That’s why a comprehensive dilated eye exam is very important.
It can help your eye care professional determine what level of eye pressure
is normal for you.
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| What can I do to protect my vision? |
Studies have shown that the early detection and treatment of glaucoma,
before it causes major vision loss, is the best way to control the disease.
So, if you fall into one of the high-risk groups for the disease, make
sure to have your eyes examined
through dilated pupils every two years by an eye care professional.
If you are being treated for glaucoma, be sure to take your glaucoma medicine
every day.
See your eye care professional regularly.
You also can help protect the vision of family members and friends
who may be at high risk for glaucoma—African Americans over age 40, everyone
over age 60,
especially Mexican Americans; and people with a family history of the disease.
Encourage them to have a comprehensive dilated eye exam at least once every
two years.
Remember: Lowering eye pressure in glaucoma’s early stages slows
progression of the disease and helps save vision.
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| Symptoms and Detection |
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 glaucoma remains untreated, people may miss objects to the side and
out of the corner of their eye.
Without treatment, people with glaucoma will slowly lose their peripheral
(side) vision.
They seem to be looking through a tunnel. Over time, straight-ahead vision
may decrease until no vision remains.
Glaucoma can develop in one or both eyes.
Normal Vision → Defect appeared in vision →Actual vision (Image)
  
The black part is unseen. With a normal view, the blind spot is only black.
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| How is glaucoma detected? |
Glaucoma is detected through a comprehensive eye exam that includes:
1 Visual acuity test.
This eye chart test measures how well you see at various distances.
A tonometer measures pressure inside the eye to detect glaucoma.
2 Visual field test.
This test measures your side (Peripheral) vision.
It helps your eye care professional tell if you have lost side vision,
a sign of glaucoma.
3 Dilated eye exam.
Drops are placed in your eyes to widen, or dilate, the pupils.
Your eye care professional uses a special magnifying lens
to examine your retina and optic nerve for signs of damage and other eye
problems.
After the exam, your close-up vision may remain blurred for several hours.
4 Tonometry.
An instrument measures the pressure inside the eye. Numbing drops may be
applied to your eye for this test.
5 Pachymetry.
A numbing drop is applied to your eye.
Your eye care professional uses an ultrasonic wave instrument to measure
the thickness of your cornea.
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| Instruments used for glaucoma tests |
Heidelberg Retina TomographⅡ
Screen analysis of the optic disk shape by Heidelberg Retina TomographⅡ
The red part of this picture is the excavation of optic nerve head.
The wider and deeper the red part is, the suspicion of glaucoma grows.
The X mark shows abnormal points.
This is the screen analysis of a normal ocular fundus.
OCT (Optical Coherence Tomography)
OCT (Optical Coherence Tomography) is a test to shoot a fault screen of
the retina.
This test clarifies the condition of the retina, which is difficult to
diagnosis,
and helps to decide treatment plans for retina disease.
OCT is necessary for diseases such as macular hole, diabetic maculopathy,
macular edema, age-related macular degeneration, detachment of the retina,
and glaucoma.
Cases of test results
Normal section of the retina 
Section of macular edema. 
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| What can I do if I already have lost some vision from glaucoma? |
If you have lost some sight from glaucoma, ask your eye care professional
about low vision services
and devices that may help you make the most of your remaining vision.
Ask for a referral to a specialist in low vision.
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Director:Tomoko Nishioka
(A board-certified ophthalmologist Ph.D)
Memberships
Japan Ophthalmological Society
Japan ophthalmlogists Association
Career
1998 Graduate-Medical Department of Mie University
2003 Doctorate-Tokyo Medical and Dental University
2003 Department of Ophthalmology of Nagareyama
General Hospital
2005 Shinjuku-Higashiguchi Eye Clinic
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Yasuharu Noma
(A board-certified ophthalmologist)
Memberships
Japan Opthalmological Society
Japan Opthalmologists Association
Japan Glaucoma Society
The Japanese Neuro-Opthalmology Society
Career
1998 Graduate- Okayama University Faculty of Medicine
1999 Miyoshi Central Hospital
2001 Hiroshima Railway Hospital
2002 Chugoku Rosai Hospital
2003 Hiroshima University Hospital
2004 Miyoshi Central Hospital
2008 Shinjuku-Higashiguchi Eye Clinic
Main Research Presentations
“The effect of Betaxolol towards the progression of visual field defect
in Glaucoma”
“The retinal nerve fiber layer thickness in glaucoma cases examined by
2 types of Optical Coherence Tomographys”
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We have 2 full-time service orthoptists, 1 part-time orthoptist, and 2
part-time nurses in our clinic.
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Another several ophthalmologists are working here.
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