Eye Conditions & Diseases

Glaucoma

Glaucoma is a degenerative disease that can cause permanent damage to the optic nerve.  This damage will result in gradual loss of vision and eventual blindness if left untreated.  Almost three million Americans have glaucoma. Half of these people are not aware that they have the disease. Of those who have been diagnosed with glaucoma, about 120,000 are blind. Moreover, glaucoma is a leading cause of blindness in older adults and in blacks over age 40.

How does open-angle glaucoma damage the optic nerve?

Damage is usually caused by an elevated pressure (IOP).  Aqueous humor, a clear fluid, circulates through the eye providing nourishment to the tissues to maintain pressure and the shape of the eye.

When there is an increase in fluid production or a decrease in fluid drainage, Open Angle Glaucoma (OAG) occurs.  As the optic nerve fibers are destroyed, peripheral or side vision is lost.

Does increased eye pressure mean that I have glaucoma?

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 your eye care professional.

Can I develop glaucoma without an increase in my eye pressure?

Yes. Glaucoma can develop without increased eye pressure. This form of glaucoma is called low-tension or normal-tension glaucoma. It is not as common as open-angle glaucoma.

Who is at risk for open-angle glaucoma?

Anyone can develop glaucoma. Some people are at higher risk than others. They include:

• African Americans over age 40.
• Everyone over age 60, especially Mexican Americans.
• People with a family history of glaucoma.

A comprehensive dilated eye exam can reveal more risk factors, such as high eye pressure, thinness of the cornea, and abnormal optic nerve anatomy. In some people with certain combinations of these high-risk factors, medicines in the form of eye drops reduce the risk of developing glaucoma by about half.

What are the symptoms of glaucoma?

At first, open-angle glaucoma has no symptoms. It causes no pain. Vision stays normal.

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 visual acuity remains.

Glaucoma can develop in one or both eyes.

Normal vision Same scene as viewed by a person with glaucoma

How is glaucoma detected?

Glaucoma is detected through a comprehensive eye exam that includes:

Visual acuity test. This eye chart test measures how well you see at various distances.

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.

Tonometry. An instrument (right) measures the pressure inside the eye. Numbing drops will be applied to your eye for this test.

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.

Can glaucoma be cured?

What are the treatments for glaucoma and when should I start treatment?

Immediate treatment for early stage, open-angle glaucoma can delay progression of the disease. That's why early diagnosis is very important.

Glaucoma treatments include eye drops, laser surgery and conventional surgery, or a combination of any of these. While these treatments may save remaining vision, they do not improve sight already lost from glaucoma.

Eye drops are commonly used by most eye care professionals to treat and control glaucoma.  Drops can be very expensive, messy, and have unwanted side effects.

Selective Laser Trabeculoplasty (SLT) is an advancement over other treatments and has been safely and effectively used in the treatment of open angle glaucoma.

At Garrett Eye Center, Dr. John Michael Garrett has always offered his patients the most advanced technology to treat the loss of vision.  Dr. Garrett is the first and only ophthalmologist in the Upper Peninsula of Michigan to offer his patients Selective Laser Trabeculoplasty (SLT).  This revolutionary glaucoma treatment is performed in the office and does not rely on drops:  it uses an advanced laser system to target only specific cells of the eye.  As a result of targeting only those cells that contain melanin (a natural pigment) your body's own healing response helps lower the pressure in your eye.

Benefits of the SLT are:  It is safe; the SLT is not associated with systemic side effects or the cost of expensive medicines: It is selective;  the SLT utilizes selective photothermolysis to target only specific cells leaving the surrounding tissue intact.  It is smart;  the SLT stimulates the body's natural mechanisms to enhance outflow of the fluid in your eye.  It is sensible;  the SLT is reimbursed by Medicare and many other insurance providers, which minimizes your out-of-pocket expenses.

Glaucoma has no associated pain.  Vision loss from glaucoma is permanent, but usually can be prevented with early detection and treatment.  If you are interested in learning more about this exciting laser treatment for glaucoma your may contact Dr. John Michael Garrett or call the Garrett Eye Center.

Although it is rare, like any surgery, laser surgery can cause side effects such as inflammation. Your doctor may give you some drops to take home for any soreness or inflammation inside the eye. You need to make several follow-up visits to have your eye pressure monitored.

If you have glaucoma in both eyes, only one eye will be treated at a time. Laser treatments for each eye will be scheduled several days to several weeks apart.

Conventional surgery. Conventional surgery makes a new opening for the fluid to leave the eye. (See diagram.) Your doctor may suggest this treatment at any time. Conventional surgery often is done after medicines and laser surgery have failed to control pressure.

Conventional surgery is performed in an eye clinic or hospital. Before the surgery, you will be given medicine to help you relax. Your doctor will make small injections around the eye to numb it. A small piece of tissue is removed to create a new channel for the fluid to drain from the eye.

For several weeks after the surgery, you must put drops in the eye to fight infection and inflammation. These drops will be different from those you may have been using before surgery.

As with laser surgery, conventional surgery is performed on one eye at a time. Usually the operations are four to six weeks apart.

Conventional surgery is about 60 to 80 percent effective at lowering eye pressure. If the new drainage opening narrows, a second operation may be needed. Conventional surgery works best if you have not had previous eye surgery, such as a cataract operation.

In some instances, your vision may not be as good as it was before conventional surgery. Conventional surgery can cause side effects, including cataract, problems with the cornea, and inflammation or infection inside the eye. The buildup of fluid in the back of the eye may cause some patients to see shadows in their vision. If you have any of these problems, tell your doctor so a treatment plan can be developed.

Conventional surgery makes a new opening for the fluid to leave the eye.

What are some other forms of glaucoma?

Open-angle glaucoma is the most common form. Some people have other types of the disease.

In 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.

A comprehensive medical history is important in identifying other potential risk factors, such as low blood pressure, that contribute to low-tension glaucoma. If no risk factors are identified, the treatment options for low-tension glaucoma are the same as for open-angle glaucoma.

In 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 nausea, as well as redness of the eye and blurred vision. If you have these symptoms, you need to seek treatment immediately. This is a medical emergency. If your doctor is unavailable, go to the nearest hospital or clinic. Without treatment to improve the flow of fluid, the eye can become blind in as few as one or two days. Usually, prompt laser surgery and medicines can clear the blockage and protect sight.

In 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.

Secondary glaucoma can develop as a complication of other medical conditions. These types of glaucoma 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.

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. Many community organizations and agencies offer information about low vision counseling, training, and other special services for people with visual impairments.

What can I do to protect my vision?

 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.

Medicare covers an annual comprehensive dilated eye exam for some people at high risk for glaucoma. These people include those with diabetes, those with a family history of glaucoma, and African Americans age 50 and older.

Today, patients take an active role in their health care. Be an active patient about your eye care.