Glaucoma

Glaucoma is an eye disease that is one of the leading causes of blindness in the United States.

Glaucoma is fairly common in adults over age 35. Approximately 5% of persons in this age group have vision threatened by this disease. When diagnosed early, blindness from glaucoma is almost always preventable.

THE SIDE (PERIPHERAL VISION) IS USUALLY AFFECTED BEFORE THE CENTRAL VISION AND THEREFORE PEOPLE OFTEN DO NOT NOTICE ANY SYMPTOMS.

A view of the optic nerve. Normal vs. Glaucoma- Loss of nerve tissue INCLUDEPICTURE "http://vec2020.com/images/C60.jpg" \* MERGEFORMATINET INCLUDEPICTURE "http://vec2020.com/images/C56.jpg" \* MERGEFORMATINET

When we look at an object, the image is carried from the retina to the brain by the nerve of sight (the optic nerve). This nerve is like an electric cable. It contains a million wires, each carrying a message to the brain, which join together to provide side vision, as well as sharp, central reading vision. Glaucoma can produce damage to the "wires," causing blind spots in areas of vision to develop. People seldom notice these blind areas in the side vision until considerable optic nerve damage has occurred. If the entire nerve is destroyed, blindness results. Fortunately, this rarely occurs if glaucoma is diagnosed and treated before major damage has taken place.

The key to preventing optic nerve damage or blindness from glaucoma is early diagnosis and treatment. Many doctors can test for glaucoma as part of a periodic physical examination. Medical eye examinations from your eye care professional are the best defense against glaucoma.

Causes and Symptoms

A clear transparent liquid called aqueous humor flows through the inner eye continuously. This inner flow can be compared to a sink with a faucet turned on all the time. If the drainpipe gets clogged, water collects in the sink. If the drainage system of the eye gets similarly blocked, the fluid pressure within the inner eye is increased and can cause damage to the optic nerve.

Blockage of the "pipes" can occur in four ways:

Most commonly, the drainage system can be clogged with deposits and cellular material over the years. This partial blockage causes a gradual build-up of pressure within the eye.  This is known as chronic open angle glaucoma because it develops slowly over a period of time.  Most adult glaucoma patients have this type of glaucoma.  Chronic open angle glaucoma can steal vision so quietly that the patient is often unaware that they are losing vision as there is no pain.  Because no symptoms occur, the best way to diagnose this form of glaucoma is by periodic eye examinations.

Second, the drainage system of the eye may be poorly formed.  This type of defect is seen in congenital glaucoma when the drainage openings are abnormal from birth.   Since an infant's eye has more elasticity than an adult's, when pressure inside the eye is increased, the easily stretchable eye may enlarge. The front of the eye may become cloudy like fog on a windshield. The infant may be sensitive to light and tear excessively. This is a rare condition. However, such symptoms or other suspicion of trouble in the eyes of an infant or child should lead to an immediate visit to a pediatric ophthalmologist.

Third, in some cases of glaucoma, parts of the eyeâ™s anatomy may completely or partially obstruct the drainage system of the eye.  This is the case in narrow angle glaucoma.  The iris in this case vaults forward in the eye blocking the drainage channels and, therefore, increases intraocular pressure dramatically and more acutely than in chronic open angle glaucoma.   Such sudden, complete blockage of fluid flowing out of the eye results in acute angle-closure glaucoma. Blurred vision, severe pain, rainbow haloes around lights, nausea and vomiting should bring the patient quickly to an eye physician. Unless this condition is relieved promptly, blindness can result in a day or two.

Fourth, other conditions including injuries, certain drugs, hemorrhages, tumors, and inflammations can sometimes block outflow channels in the eye. This may increase inner eye pressure and lead to secondary glaucoma.

Glaucoma Types and Testing

Chronic glaucoma

The most common type of glaucoma is painless. Left untreated, it slowly destroys vision. In fact, most people who have chronic glaucoma are not aware that they are gradually robbed of their eyesight.  In most cases, there are no warning symptoms and, by the time vision problems develop, irreversible visual damage may already have occurred.

Acute glaucoma

Is not nearly as common as chronic glaucoma. Unlike the gradual destruction of vision that occurs in the chronic condition, acute glaucoma is marked by sudden severe pain in and around the eye and is often accompanied by nausea and vomiting. In order to alleviate the pressure and prevent further eye damage, emergency treatment, usually laser surgery, is required.

Screening for Glaucoma

In an effort to catch glaucoma early, screening has become widespread and may initially be done by a wide variety of health professionals. Your ophthalmologist may test your eye pressure. If the screening suggests that your pressure is elevated, further tests will be performed to establish the diagnosis of glaucoma. Because chronic glaucoma seldom causes symptoms, it's extremely important for you to have a thorough eye exam around age forty- even if you have no complaints about your vision.

The Glaucoma Exam

Often a general eye examination begins with a visual acuity test that determines how sharp your vision is. Using one eye at a time, you'll read a chart of letters or numbers of varying sizes from a set distance (often twenty feet). Then you may be asked to view the chart through an instrument known as a refractor. By shining a light through the refractor onto the retina, your doctor can determine if you need glasses.

A slit lamp is a microscope that magnifies and illuminates the cornea, iris, and lens. It aids your doctor in finding conditions such as cataracts and corneal problems. After your vision is checked, your doctor will examine the internal structures of the eye, including the optic nerve. Using an ophthalmoscope, a hand-held instrument, the doctor can see changes in the optic nerve that are characteristic of glaucoma. After the routine examination is completed, a series of specially designed tests are given to help in the specific diagnosis of glaucoma.

The diagnosis of glaucoma is confirmed by an array of diagnostic tools that allow your eye doctor to identify signs of glaucoma long before you have any symptoms. Your doctor may begin with tonometry, which measures the pressure in your eye. Another important test checks your side (peripheral) and central vision. Your doctor may examine the interior structures of your eye using gonioscopy- a special mirrored lens. If glaucoma is diagnosed, your progress will be closely monitored during regular examinations.

Diagnostic Testing

Your examination will test your field of vision, including peripheral and central vision. This test is helpful in determining if your vision has begun to be affected-and, if so, to what extent. Your doctor may use the computerized vision test or the Goldmann perimeter screen test. One eye is tested at a time.

During the computerized vision test, the examiner will ask you to place your chin on a stand in front of a screen connected to a computer. While looking straight ahead, you press a button whenever a light appears in view. The computer provides a printout of your field of vision. The Goldmann perimeter screen test is similar except that a computer is not used. An examiner records your responses as you indicate when a light comes into view. With the tangent screen test, the examiner uses a marker in place of a light to map your field of vision.

Another test, called gonioscopy, involves gently placing a special lens that contains a mirror on your eye. The doctor can look inside your eye to see the drainage area that can be a problem in glaucoma. Because the area between the iris and the cornea can be seen, this test is especially helpful in determining whether the angle between the cornea and iris has been narrowed. Gonioscopy may help your doctor diagnose the type of glaucoma you have.

What happens after diagnostic testing?

Once your diagnostic tests have been completed and glaucoma has been diagnosed, your doctor may monitor the progression of the disease with special photographs of the optic nerve. Your doctor can check for progressive enlargement of the optic cup, which indicates continuing damage from the elevated eye pressure. Your doctor may also note blood vessel changes in the optic cup, another sign of glaucoma progression. A special camera for photographing the optic nerve is often used during your eye examinations. Your doctor will advise you how often your eyes will need to be checked.

Occasionally, a person may have a "borderline" eye pressure, which means that, although the pressure is elevated, there is no evidence of glaucoma damage. If you are a glaucoma suspect with a borderline pressure, your doctor may not prescribe medication immediately. Instead, your pressure will require monitoring by your doctor so that if changes do occur, treatment can be started.

Can glaucoma be inherited?

Glaucoma tends to run in families, and if either of your parents or any of your grandparents had it, you have a higher than average chance of developing the disease. Although glaucoma is rare in children, it is a leading cause of blindness in people over forty.

What is the treatment for Glaucoma?

Glaucoma is usually controlled with eye drops given 1 to 2 times a day given in various combinations. These medications act to decrease eye pressure either by assisting flow of fluid out of an eye or by decreasing the amount of fluid entering the eye. To be effective, these medications must be taken regularly and continuously.

Patients with any type of glaucoma need periodic examinations. Glaucoma sometimes gets worse (or better) without the patient being aware of it, and as a result, treatment may need to be changed after awhile. As a rule, damage caused by glaucoma cannot be reversed. Eye drops, laser and surgery are used to prevent further damage from occurring, and to preserve existing vision.

Glaucoma and You

Control of glaucoma by drugs can only be effective if patients adhere to the treatment schedule prescribed by their eye doctor. The treatment "team" is made up of both you and your doctor. Medication should never be stopped without first consulting your doctor. It is always important to inform all the physicians you visit about the eye medications you are using. Remember, it is your vision, and you must do your part in maintaining it.

Whenever you visit any doctor or other health care professional, be sure to tell him or her the name of the glaucoma medication youâ™re taking. This could be especially helpful if an emergency arises.

Take extra medication with you when you plan to be away from home for a few days. In fact, it's a good idea to always keep an extra supply of medication on hand in case a supply is lost or destroyed. Be sure to tell our eye care professional if your medication causes any side effects. It may be possible for another drug to be substituted.

Because glaucoma runs in families, encourage adult members of your family to have regular eye checkups.

Loss of Vision is Largely Preventable

If you are over age 35, you should have your eyes checked for glaucoma every 1-3 years. Your Ophthalmologist should be consulted whenever there is any decrease in vision or recurrent pain, or when any of the other symptoms discussed in this brochure are present. When diagnosed promptly, eye pressure can be brought under control and future glaucoma attacks can be prevented.

Glaucoma Treatment

Treatment for Open-Angle type glaucoma

The risks and side effects of glaucoma treatment are less than leaving the glaucoma untreated.

Glaucoma Medication

Drop medications work by limiting fluid production and decreasing the flow of fluid into the eye. The medication is usually taken one to two times a day. In order to control your eye pressure and prevent damage to your vision, you will need to take your medication every day for the rest of your life.

Glaucoma Surgery Facts

Sometimes treatment with eye drops does not control the pressure in your eye, or your doctor for your particular situation does not recommend those treatments. If so, there are surgical means to lower intraocular pressure. Your eye care professional may recommend either trabeculoplasty (laser treatment) or trabeculectomy (traditional surgery). Both techniques involve treating the trabecular meshwork; the drainage area that can clog up and cause elevated eye pressure.

Laser Treatment- What is a Trabeculoplasty? A.K.A. SLT or ALT

To improve the flow of fluid through the trabecular meshwork, your doctor will use the argon laser or a selective YAG laser in that area of the eye. You will be given anesthetic drops and asked to rest your chin on the platform that is connected to the slit lamp and the laser. You will be asked to remain still, allowing your doctor to direct the laser to the exact part of your eye where the surgery is needed. The procedure takes about 2 to 5 minutes. The procedure is essentially painless. Your doctor may want to check your eye pressure later that same day. It may take a few weeks for the full effect of the laser treatment to be seen, and you may need to continue taking medication. It is possible that trabeculoplasty may have to be repeated at a later time but can work as well as medicine in many cases.

Surgery- What is a Trabeculectomy?

In a trabeculectomy, a section of the trabecular meshwork is removed to enable the fluid to drain from your eye and reduce intraocular pressure. A local or general anesthetic will be used. After surgery, you probably will go home that day and rest. Your doctor will want to see you the next day to check your vision and eye pressure. You may need to use medication after your treatment.

Treatment of Closed-Angle Glaucoma Laser Iridotomy

Laser iridotomy is a surgical procedure used to treatangle-closure glaucoma and those at risk for angle-closure glaucoma.

Symptoms of angle-closure glaucoma attack include:

• Severe ocular pain and redness
• Decreased vision
• Colored halos around lights
• Headache
• Nausea
• Vomiting

Because raised eye pressure can damage the optic nerve and lead to vision loss, an angle-closure glaucoma attack must be treated immediately.  Patients who are at risk for developing angle-closure glaucoma should have laser iridotomy.

What happens?

During laser iridotomy, a small hole is made in the iris to create a new way for the fluid to drain from your eye. The new hole restores the balance between fluid entering and leaving your eye, lowering eye pressure. The surgery is performed by an eye care professional on an outpatient basis. Your eye will be numbed with eye drops. A contact lens is place on your eye to be used as a guide for the laser. A hole about the size of a pinhead is made on your iris. The actual procedure will only take a few minutes. You should plan to have someone drive you home after the procedure.

Following Laser Iridotomy

After laser iridotomy you will be able to go home and resume normal activities. Medication may be prescribed. Your eye doctor may want to check the pressure in your eye later that day. Laser iridotomy prevents further eye damage by relieving the high pressure, but it cannot restore vision that was damaged during the acute attack. A partial loss of sight in the affected eye is often the consequence of an acute attack.

Can acute glaucoma affect both eyes?

If you have an attack of acute glaucoma in one eye, you often will have an attack in the other eye eventually. Your Ophthalmologist may recommend preventive laser iridotomy or surgical iridectomy to guard against an attack in the second eye. When either is performed before an acute attack occurs, the chances for successful surgery (preventing loss of vision) are greater.

Because glaucoma runs in families, encourage adult members of your family to have regular eye checkups. Loss of Vision is Largely Preventable

If you are over age 35, you should have your eyes checked for glaucoma at least every 1-3 years. Your eye care professional should be consulted whenever there is any decrease in vision or recurrent pain, or when any of the other symptoms discussed in this brochure are present. When diagnosed promptly, eye pressure can be brought under control and future glaucoma attacks can be prevented.