Glaucoma.

Glaucoma is one of the leading cause of blindness throughout the world, affecting approximately 2% of the population over the age of 40. Unlike many other eye diseases, conditions or problems, glaucoma begins without any symptoms or obvious loss of vision. Often called the sneak thief of sight, glaucoma can destroy sight without causing any pain or obvious symptoms until it is too late. Thus, early detection of glaucoma is extremely important. This disease can often be successfully treated, and blindness prevented, when diagnosed early enough. We invite you to make an appointment and learn more: 480-981-6111.

What is glaucoma? How glaucoma works Risk factors of glaucoma Types of glaucoma Diagnosing glaucoma Treatment of glaucoma

What is Glaucoma?

A complex eye disease, glaucoma is not simply an elevated intraocular pressure. Glaucoma is actually a broad term that is used to characterize a range of eye conditions that damage the optic nerve and potentially cause loss of vision. Glaucoma therefore is a disease of the optic nerve, the vital nerve bundle that carries images to your brain so you can see.

Glaucoma usually affects both eyes, but can progress more rapidly in one eye than in the other. Involvement of just one eye primarily occurs when glaucoma is brought on by factors such as a prior injury or the use of steroids in that eye.

How Glaucoma Works

The eyeball is basically a rigid sphere filled with aqueous humor. In the normal eye, there is a constant production and drainage of this fluid. This production and drainage is balanced so as to maintain a “normal' intraocular pressure (IOP). As the total amount of fluid within the eye increases, so does the pressure. Many people relate glaucoma to increased pressure inside the eye, although that is not the only cause, but is a common cause of glaucoma. The higher the pressure inside the eye, the greater the chance of damage to the optic nerve.

Imagine that a healthy eye is like a water balloon attached to a faucet that is permanently dripping water. The balloon has a drainpipe that slowly filters the water out, at a constant rate, allowing the balloon to stay perfectly full without overextending it. However, if the drainpipe were clogged, the water would collect inside the balloon and over-inflate it, creating too much pressure. Eventually, the most fragile part of the balloon would become damaged and give way.

In your eye, the liquid is called aqueous humor and constantly flows in and out, not as a part of the tears on the outer surface, but rather coming from inside your eye and leaving through a drainpipe called the angle (because of its angular shape). If the angle becomes blocked, the volume of fluid inside the eye goes well beyond normal levels, putting too much pressure on the fragile optic nerve and damaging it (see illustration at the top of this page).

The diagram at the right is of the front part of the eye, in cross section, to show the filtering, or drainage angle. The angle is between the cornea and the iris, which join each other right where the drainpipe (called the trabecular meshwork) is located. The purple arrow in the diagram shows the flow of the aqueous fluid from the ciliary body, through the pupil, and into the drainage channels.

Glaucoma can affect anyone. While high pressure in the eye is considered the primary reason for glaucoma, even patients with normal eye pressure have been known to contract this disease. At East Valley Ophthalmology, your eye doctor puts together many kinds of information to determine your risk for developing glaucoma. If detected early, loss of vision can most often be prevented.

Risk Factors of Glaucoma

Factors that increase a person's risk generally include:

· Increased Intraocular Pressure (IOP) - Anyone who has been found to have an elevated intraocular pressure at a glaucoma screening or as part of a general eye examination is considered to be at risk for developing glaucoma.

· Increasing Age - The incidence of glaucoma increases as we get older. Typically the incidence of glaucoma becomes much more noticeable above the age of 40 years old. This is why routine eye examinations with glaucoma evaluation are recommended every 2 years above the age of 40, if there is no other family or medical history, and more often if there is a preexisting history of glaucoma in the family or other predisposing heath factors.

· Race - African-Americans to have certain genetic factors that cause a higher likelihood of developing glaucoma.

· High Blood Pressure - Those patients who are being medically treated for high blood pressure may be at greater risk for glaucoma due to the lowering of the blood pressure within the optic nerve.

· Family History of Glaucoma - Family history of glaucoma is a very significant risk factor. If any other family members have been diagnosed with glaucoma, your risk of developing glaucoma increases considerably. This is particularly true for siblings of glaucoma patients, who have a 5-fold increase in risk for developing glaucoma.

· Diabetes - Anyone being treated for diabetes is considered to be at greater risk for glaucoma due to the general circulation problems associated with diabetes.

· Myopia (nearsightedness) - In general patients who are nearsighted have anatomical features that may increase the risk of glaucoma.

· Long-term Steroid Treatment

· Injury/Trauma To The Eye

Types of Glaucoma

The eye's drainage system, which lies in-between the cornea and the iris, is called the angle, named for its angular shape. Therefore, you see the word angle in the different glaucoma names. While there are many types of glaucoma, they primarily fall into two groups, differentiated according to whether the angle is open (able to accept fluid) or closed (fluid is blocked from entering).

Open Angle Glaucoma

Open angle glaucoma is chronic — develops over time.

Closed Angle Glaucoma (Angle-Closure Glaucoma)

Closed angle glaucoma is acute — can occur suddenly.

Primary Open Angle Glaucoma PAG

By far, the most frequently diagnosed type of Glaucoma in the United States is primary open angle glaucoma (POAG). Patients with primary open angle glaucoma typically demonstrate an increase in intraocular pressure (IOP) upon routine measurement. The increased intraocular pressure results from either too much aqueous humor being produced or too little being drained. This fluid buildup within the closed space of the inside of the eye elevates the pressure. It is this raised pressure that can cause permanent changes and even damage to the optic nerve resulting in vision loss.

Since the optic nerve is the connection between the retina and the brain and is responsible for communicating visual images, once the optic nerve is damaged, vision can no longer function. This is why it is so important to monitor, detect and control intraocular pressure. If left untreated, an elevated intraocular pressure may, over time, cause slow progressive, permanent damage to the optic nerve that can result in blindness.

Initially, open-angle glaucoma has no symptoms. There is no pain or noticeable change in vision. Loss of peripheral (vision off to the side) is the earliest symptom. Left untreated the field of vision will continue to narrow, leading to tunnel vision, eventually to blindness.

Closed Angle Glaucoma (Angle-Closure Glaucoma)

Acute angle-closure glaucoma is an emergency and should be treated immediately. Closed-angle glaucoma occurs when fluid cannot escape because the drainage angle is closed off, which causes pressure to build up suddenly. This often causes noticeable pain.

Angle closure glaucoma is found much less frequently than open angle glaucoma, but it has the ability to produce considerable vision loss in a short period of time. While there can be a number of causes of closed angle glaucoma, it is most often caused by anatomical changes within the internal structures of the eye.

Acute closed angle glaucoma is structurally different from open angle. With closed angle glaucoma, the fluid in the eye cannot get to the drainage meshwork (trabecular meshwork) because the clogging is before the meshwork. In contrast, with open angle glaucoma the clogging is within the drainage meshwork itself.

The trabecular meshwork is actually a tiny tissue filter that, if blocked by a change in size or shape of the tissue, will cause the intraocular pressure to elevate. In instances where the meshwork becomes blocked abruptly, it will cause a sudden rise in the intraocular pressure. This sudden rise in pressure can cause pain, redness, blurred vision and if left untreated permanent loss of vision.

Closed angle glaucoma is considerably more common in farsighted eyes, which tend to be smaller, and in patients between the ages of 45-60 years of age where the crystalline lens is beginning to swell.

During your general eye exam, if your eye doctor observes or measures a narrowed angle, he will perform an additional examination procedure called Gonioscopy to fully visualize the meshwork and the angle in order to carefully assess your predisposition to angle closure glaucoma. This test is performed by placing a special contact lens on the eye and then using the slit lamp biomicroscope to fully examine the meshwork and the angle. In the event that you are at risk for angle closure glaucoma, or in the event that you have acute angle closure glaucoma, the most effective form of treatment is to use a laser to produce a small opening or hole in the iris so that aqueous humor can quickly and efficiently drain from the eye by preventing the trabecular meshwork from being blocked.

Secondary Glaucoma

Glaucoma resulting from congenital, ocular or systemic conditions represent secondary glaucoma.

The six most common forms of secondary glaucoma:

• Exfoliation syndrome
• Pigmentary glaucoma
• Neovascular glaucoma
• Lens induced glaucoma
• Glaucoma accompanied by ocular inflammation
• Trauma induced glaucoma

Diagnosing Glaucoma

Routine eye examinations are mandatory because, in its early stages, glaucoma usually has no symptoms. In order to be controlled, glaucoma must be diagnosed early. It is a lifelong disease, so those afflicted must be compliant for the rest of their lives and religiously keep to their scheduled eye exams and with their medication regimens.

A glaucoma exam includes:

· Measuring your intraocular pressure (tonometry)

· Inspecting the drainage angle of your eye (gonioscopy)

· Evaluating any optic nerve damage (ophthalmoscopy)

· Testing the visual field of each eye (perimetry)

Some of these tests may not be necessary for every person. You may need to repeat these tests on a regular basis, to determine if glaucoma damage is increasing over time.

When should you have a glaucoma exam?

· Under age 45

With risk factors = every 2 years.
Without risk factors = every 4 years.

· Over age 45

With risk factors = every year.
Without risk factors = every 2 years.

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Treatment Of Glaucoma

As a rule, damage caused by glaucoma cannot be reversed. Therefore, the goal in the management of glaucoma is to reduce the intraocular pressure to the point whereby the remaining healthy nerve fibers are able to receive proper nourishment and maintain the remaining function. Proper treatment can keep the intraocular pressure within normal range and therefore prevent or retard further nerve damage and visual loss.

Eye Drops for Glaucoma

Open angle glaucoma is usually controlled with eye drops taken several times a day , sometimes in combination with pills. There are many types of eye drops available that can lower the intraocular pressure. By using a single type of medication or sometimes 2 eye drops in combination, more than 80% of the patients with open angle glaucoma can be successfully treated.

One or more types of eye drops may have to be taken up to several times a day in order to be effective. These medications are used to prevent damage to the optic nerve by decrease eye pressure, either by slowing the production of aqueous fluid within the eye or by improving the flow leaving the eye. Recently there have been a few brand new medications which show great promise for more effectively than others. In order for these medications to work, you must take them regularly and continuously as they were prescribed. The vital key to the success of medication therapy is patient compliance.

Laser Surgery for Glaucoma

Some patients experience side effects of these eye drops and it makes the use of eye drops a poor treatment option. Also, some patients are unable to achieve adequate control with eye drops alone and require laser treatment in addition to the eye drops in order to maintain control. The laser is usually used in one of two ways"

Open Angle Glaucoma

Treatment for open angle glaucoma involves the drain itself. In open-angle glaucoma, the laser is used to enlarge the drain (argon laser trabeculoplasty) to help control eye pressure.

Closed Angle Glaucoma (Angle-Closure Glaucoma)

In angle-closure glaucoma, the laser creates a hole in the iris (iridotomy) to improve the flow of aqueous fluid to the drain.

Surgical Treatment of Glaucoma

For a small number of patients, it is still not possible to achieve good stable control and stop the progression of glaucoma. For these patients there are surgical procedures including removing a tiny piece of the trabecular meshwork or even implanting a microscopic glaucoma valve that can be performed to help reduce and stabilize the intraocular pressure and prevent vision loss.

When operative surgery is needed to control glaucoma, your eye surgeon creates a new drainage channel (bleb) through which the aqueous fluid can leave the eye, thereby lowering the IOP.

Fortunately, technology has improved significantly for both the medication and laser treatment alternatives in glaucoma, so that only a very few individuals need ever progress to the point of needing surgery. The key to a lot of these successes however, lie in prevention; specifically, the earlier that glaucoma can be diagnosed, the more effective the treatment through either medications or laser.

The eye specialists of East Valley Ophthalmology perform advanced technology diagnostic testing and treatment, as well as taking the time necessary to provide each patient with information needed to fully understand their condition and to achieve their best possible visual outcome.

If you would like further information, please call our office at:

480-981-6111

East Valley Ophthalmology

Eye Doctors - Mesa, Arizona

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