GLAUCOMA
History
Frequently Asked Questions (FAQ's)
POAG (primary open-angle glaucoma)
Pigment dispersion glaucoma
Pseudoexfoliation glaucoma
Narrow angle / closed angle glaucoma
Acute Angle closure (sudden attack glaucoma)
Therapy
HISTORY
Glaucoma was recognized as early as 400 BC. In the 1800's, glaucoma was recognized as a distinct disorder, although it frequently coexisted with cataracts.
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FREQUENTLY ASKED QUESTIONS (FAQ's):
WHO GETS GLAUCOMA?
Glaucoma accounts for blindness in more than 5 million persons. It is the leading cause of blindness in African Americans and the second leading cause overall in the United States. Glaucoma typically occurs after 40 years of age, although there are several types of glaucoma that present at an earlier age.
WHO IS AT RISK?
Risk factors or associations for development and progression of glaucoma include advancing age, family history, African American race, nearsightedness, hypertension, diabetes, high cholesterol, smoking, and thyroid disease.
WHAT IS GLAUCOMA?
In glaucoma, the optic nerve - the nerve that gives you your vision, which comes off the brain - becomes compressed. This is how you lose your vision.
WHAT CAUSES GLAUCOMA?
Glaucoma is a multifactorial disease. Current theories include increased pressure within the eye, decreased blood flow to the eye, and genetics.
ARE THERE ANY SYMPTOMS?
Glaucoma usually presents without any symptoms and thus is called the "sneak thief of sight." At first you may lose your side vision, which may be unnoticeable to you. Late in the disease, after much of the optic nerve has been destroyed, you may lose your central vision, which then becomes noticeable. There are a few types of glaucoma that may have symptoms; such as glaucoma in newborns that may present with eyes that appear large and have a white hue to the front surface of the eye or sudden attack glaucoma where the eye becomes very painful and red. These, however, are a minority of cases in the United States. The majority of glaucoma is asymptomatic.
HOW WILL MY DOCTOR DETERMINE IF I GLAUCOMA?
In addition to a careful optic nerve examination and eye pressure measurement, there is a test called a visual field which can be done to determine how much of your vision has been lost. This is why it is so important to catch the disease early.
WILL I GO BLIND?
Many people are devastated when they are told that they have glaucoma. It does not necessarily mean you will go blind. It is extremely important to note that once glaucoma is diagnosed, there are a number of interventions that may be sought to prevent further vision loss or slow down the vision loss to a rate that will not affect your daily life. One of the most important factors in determining your ultimate outcome is how early the diagnosis is made. Vision that has already been lost from glaucoma may not be restored currently. However, further vision loss may be preventable.
HOW DOES GLAUCOMA DEVELOP?
In order to understand how glaucoma works, you need to think like a plumber.
If you visualize your kitchen sink, there is a faucet and a drain. In the eye, the faucet is always on (by the way, this is not the tearing system, this is a separate plumbing system inside the eye). Moreover, in our analogy, the drain is always open.
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TYPES OF GLAUCOMA:
POAG (Primary Open-Angle Glaucoma)
What comes next is rather a mystery, even today. What we believe happens is a mismatch of fluid being pumped into your eye and the amount of fluid exiting the drain (called the angle).
By placing a special mirrored contact lens on your eye, the drain may be visualized. In POAG, the drain appears to be open. However, on a microscopic level, the drain may be filled with debris, which may cause the fluid to build up in your eye (like your kitchen sink filling up with water).
Alternatively, your faucet may be working too well and overwhelming the ability of the drain to get rid of the fluid fast enough. Unlike your kitchen sink, which can spill over on the floor, the eye is contained and the fluid just builds up in the eye. The result of this is that the fluid starts to compress the other parts of the eye.
You can choose to learn about therapy now.
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Pigment Dispersion Glaucoma
In pigment dispersion, the lens of your eye is rubbing against the back surface of the colored part of your eye. This releases pigment which floats around your eye. This process may be exacerbated by exercise.
We believe there is a mismatch of fluid being pumped into your eye and the amount of fluid exiting the drain (called the angle). By placing a special mirrored contact lens on your eye, the drain may be visualized.
In pigment dispersion, the drain appears to be clogged up with the pigment floating in your eye. This may cause the fluid to build up in your eye (like your kitchen sink filling up with water). Also, your faucet may be working too good and overwhelming the ability of the drain to get rid of the fluid and pigment fast enough.
Unlike your kitchen sink, which can spillover on the floor, the eye is contained and the fluid just builds up in the eye. The result is that the fluid starts to compress the other parts of the eye.
You can choose to learn about therapy now.
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Pseudoexfoliation Glaucoma
In pseudoexfoliation, the support system (zonule) for the lens of your eye is disintegrating. Why this happens is unknown. There are undoubtedly genetic factors at work. This white flaky material floats around your eye.
We believe there is a mismatch of fluid being pumped into your eye and the amount of fluid exiting the drain (called the angle). By placing a special mirrored contact lens on your eye, the drain may be visualized.
In pseudoexfoliation, the drain appears to be clogged up with the white flaky material floating in your eye. This may cause the fluid to build up in your eye (like your kitchen sink filling up with water). Also, your faucet may be working too good and overwhelming the ability of the drain to get rid of the fluid and pseudoexfoliation material fast enough.
Unlike your kitchen sink, which can spillover on the floor, the eye is contained and the fluid just builds up in the eye. The result is that the fluid starts to compress the other parts of the eye.
You can choose to learn about therapy now.
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Narrow Angle / Closed Angle / Other Glaucomas
If there is a mismatch of fluid being pumped into your eye and the amount of fluid exiting the drain (called the angle), fluid will accumulate and cause the pressure in your eye to go up. By placing a special mirrored contact lens on your eye, the drain may be visualized.
NARROW ANGLE GLAUCOMA
In Narrow Angle Glaucoma, the entrance to the drain appears to be narrow or covered by the colored part of your eye (the iris). To place into context of our analogy, it is like a drain plug popping in and out of the drain.
CLOSED ANGLE GLAUCOMA
In Closed Angle Glaucoma, the colored part of your eye has scarred close part of the drain from being in contact with it for a long time. To place into context of our analogy, it is like a drain plug stuck into part of the drain.
OTHER GLAUCOMAS
On a microscopic level, the drain may also be filled with debris (open angle glaucoma). If both narrow angle and open angle glaucoma coexist, you have combined mechanism glaucoma.
TREATMENT FOR NARROW ANGLE /
CLOSED ANGLE / COMBINED MECHANISM
Treatment of this condition is to take a laser and place a hole directly through the colored part of your eye (the drain plug). This will allow the fluid made by your eye to have access to more of the drain and help to keep the pressure down.
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Acute Angle Closure Glaucoma (Sudden Attack)
If the colored part of your eye (the drain plug) suddenly creeps into the entire drainage system of your eye and gets stuck in there and doesn't come out on its own, the fluid in your eye will have nowhere to go. The fluid in the eye will accumulate very rapidly.
Typically one will experience pain, a red eye, colored haloes, headache, blurry vision, and even nausea. Most of the vision can be lost in a matter of hours or few days. The ability to see colors and shades of black and white rarely return to normal.
Treatment is to place a hole through the colored part of the eye as an emergency. Most of the time this can be accomplished with the aforementioned laser. However, due to the swelling to the eye, it can be very difficult to accomplish. Rarely, surgery may need to be performed urgently to create a new drainage system for the eye.
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Therapy for Glaucoma
Once you have been diagnosed with glaucoma, the goal is to stop the progression of vision loss.
DETERMINING DAMAGE
To this end, first a determination is made as to how much damage your optic nerve has sustained and how much of your corresponding vision has been lost.
A direct visualization of your optic nerve can be made and an estimate of the amount of damage inferred. A photo can be taken for comparison in the future.
The amount of vision loss can be judged with a visual field test, in which flashing lights are presented to your side and central vision by a computer and you push a button.
Once the test is over, a diagram of your vision with many measurements can be printed out and followed over time. If progression on this vision assessment test can be documented, you may need more aggressive treatment.
TREATMENTS
The goal of current glaucoma treatment is to lower pressure in the eye by turning the faucet off or by making the drain work more efficiently using eye drops.
If fluid balance cannot be restored to the level where no further optic nerve damage is occurring, laser treatment can be attempted or a new drain may be made for the eye surgically.
As you recall, high pressure in the eye is not the only contributing factor to glaucoma. The amount of oxygen that reaches the optic nerve is also important, as are genetics. Currently, nothing can be done to alter your genetics.
As far as reestablishing a sufficient oxygen level in the eye, there are no direct treatments. We believe that exercise, and control of high blood pressure, diabetes, high cholesterol, and stopping smoking may be beneficial to this end.
CONTROLLING PRESSURE
There are three major avenues for eye pressure control:
Drops: There are many exciting medications that come to market each year that can turn the faucet of the eye down or make the drain of the eye function more efficiently. This serves to lower the amount of fluid in the eye and decreases the pressure being placed on your optic nerve.
Laser: A laser may be fired directly into the drain of your eye to try to stimulate increased drainage. Again, this serves to lower the amount of fluid in the eye and decreases the pressure being placed on your optic nerve.
Surgery: The main goal of surgery is to create a new drainage system for the eye. This can be done by fashioning a trap door on the surface of the eye to allow pressure and fluid buildup to escape when there is an excess within the eye (trabeculectomy). Unfortunately, your own body can create scar tissue that may close this trap door off. Therefore, anti-scarring medications may be supplemented during and maybe after surgery around the trap door to prevent the trap door from scarring down.
Alternatively, a plastic tube can be placed into the eye connected to an implant that will drain the fluid directly out of the eye.
By no means is this a complete description of glaucoma and it is not intended to be. It is a brief synopsis made in laymen's terms. This is a quick overview of the issues that you and your doctor face in choosing the best course of action to prevent you from vision loss.
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