This publication is for people with glaucoma and for their family and friends. It offers information about open-angle glaucoma, the most common type of glaucoma. The brochure answers your questions about the causes and symptoms of this eye disease. It also describes the diagnosis and treatments for glaucoma.
What is glaucoma?
Glaucoma is a group of diseases that can damage the optic nerve of the eye. This results in some loss of vision or blindness. However, if it is treated on time, you can protect your eyes against serious loss of vision.
What is the optic nerve?
The optic nerve is made up of more than one million nerve fibers, which connect the retina to the brain (see the diagram below). The retina is the light-sensitive tissue, located in the back of the eye. It is necessary to have a healthy optic nerve to have good vision.
How does open-angle glaucoma affect the optic nerve?
In the front of the eye there is a space called the anterior chamber. A clear liquid enters and leaves this space continuously, feeding the tissues around it. The liquid leaves the anterior chamber through the open angle where the cornea and iris meet (see the diagram below). When the liquid reaches the angle it flows through a sponge-like net or mesh, and then leaves the eye.
Sometimes, when the liquid reaches the angle, it passes very slowly through this spongy mesh. When this fluid accumulates, the pressure inside the eye increases until it reaches a level where it can damage the optic nerve. When the optic nerve is damaged by increased pressure, it can cause open-angle glaucoma and some vision loss. That is why it is important to control the pressure inside the eyes.
If I have elevated eye pressure, does that mean I have glaucoma?
Not necessarily. The elevated pressure inside the eye means that you have the risk of developing glaucoma but it does not mean that you have the disease. A person only has glaucoma if they have damage to the optic nerve. If you have elevated eye pressure, but have no damage to the optic nerve, you do not have glaucoma. However, you run the risk of developing it. Be sure to follow the advice of your eye doctor.
Can I develop glaucoma if I have elevated eye pressure?
Not necessarily. Not all people who have elevated eye pressure develop glaucoma. Some people can tolerate high pressure in their eyes better than others. Also, a certain level of pressure may be high for one person but normal for another.
Whether you develop glaucoma will depend on the level of pressure that your optic nerve can tolerate without being damaged. This level is different for each person. That is why it is very important that a complete examination of the eyes with dilated pupils be done. This can help your eye doctor determine what the normal pressure level is for you.
Can I develop glaucoma without increasing the pressure in my eyes?
Yes. Glaucoma can develop without increasing pressure inside the eyes. This type of glaucoma is called low tension or normal tension glaucoma. It is not as common as open angle glaucoma.
Who is at risk of developing open angle glaucoma?
Anyone can develop glaucoma, but some people are at greater risk than others.
These people include:
- African Americans over 40 years.
- All people over 60, especially those of Mexican descent.
- People with relatives who have had glaucoma.
A complete examination of the eyes with dilated pupils may reveal other risk factors, for example, if you have elevated eye pressure, if the cornea is very thin, or if the optic nerve is abnormal. For some people who have certain combinations of these risk factors, medicine in the form of eye drops reduces the risk of developing glaucoma by almost half.
What are the symptoms of glaucoma?
At first, open-angle glaucoma has no symptoms. It does not cause pain and vision remains normal.
However, if glaucoma is not treated, people begin to notice that they no longer see as before. Without treatment, people with glaucoma slowly lose their lateral (peripheral) vision. It is as if they were looking through a tunnel. Over time, the central vision (forward) may also decrease until it is completely lost. Glaucoma can develop in one eye or both.
Normal Vision.
The same scene seen by a person with glaucoma.
How is glaucoma detected?
Glaucoma is detected through a complete eye exam that includes:
- Visual acuity test. In this test an eye chart is used to measure your sight at different distances.
- Visual field test. This test measures your lateral (peripheral) vision. It helps your eye doctor determine if you have a loss in lateral vision, a sign of glaucoma.
- Examination with dilated pupils. To dilate or enlarge the pupils, the eye doctor puts a few drops in the eyes. The eye doctor looks through a special magnifying lens to examine the retina and optic nerve to see if there are signs of damage or other eye problems. After the exam, your near vision may remain blurred for several hours.
- Tonometry An instrument (see photo) is used to measure eye pressure. For this test, the eye doctor can put a few drops to numb your eyes.
- Pachymetry A drop is applied to the eye to numb it. The oculist uses an ultrasonic wave instrument to measure the density of the cornea.
Can glaucoma be cured?
No, there is no cure for glaucoma. The vision that is lost by the disease cannot be recovered.
Can glaucoma be treated?
Yes. Immediate treatment in the first stage of open-angle glaucoma can delay disease progression. That is why it is very important that glaucoma is diagnosed in time.
Treatment for glaucoma includes medications, laser surgery (trabeculoplasty), conventional surgery or a combination of any of these methods. Although these treatments can protect your eyesight, they do not improve eyesight that you have already lost due to glaucoma.
Medicines. Commonly medications, whether in the form of eye drops or pills, are used first to treat glaucoma. Some of these medications cause the eye to produce less fluid. Other medications help drain the fluid in the eye, thereby lowering the pressure in the eye.
Before you start treatment for glaucoma, tell your eye doctor if you are taking other medications. Sometimes eye drops can interfere with the way other medicines work.
Glaucoma medications are taken or used several times a day. Most people have no problems with treatment. However, some medications can cause headaches or other side effects. For example, eye drops can cause burning, burning and redness of the eyes.
There are many medications available to treat glaucoma. If you have problems with one, let your eye doctor know. There may be a different treatment either by changing the dose or using a new medication.
Since glaucoma often has no symptoms, some people may be tempted to stop taking their medications or simply forget to do so. You need to continue using the drops or taking the pills as long as they continue to help control the pressure in the eye. Regular use is very important.
Make sure your eye doctor tells you how to apply the drops in your eyes. For some suggestions on how to use your drops for glaucoma.
Laser trabeculoplasty. Laser surgery, or laser trabeculoplasty, helps drain fluid from the eye. Your eye doctor can suggest this procedure at any time. In many cases, you will have to continue using glaucoma medications even after having this operation.
Laser trabeculoplasty is performed in your doctor’s office or an ophthalmologic clinic. Before the surgery, they will put a few drops to numb your eye. While you are sitting in front of the laser machine, your eye doctor will hold a special lens in front of your eye. A beam of high intensity light is directed at the lens and this is reflected in the mesh inside the eye. You can see flashes of green or red lights. The laser makes several burns at equal distances, which enlarge the filtration openings in the mesh. This helps improve drainage of the eye fluid.
Like any surgery, laser surgery can have side effects such as inflammation. Your eye doctor may prescribe a few drops to take home for pain or inflammation inside the eye. You should make several follow-up visits to your eye doctor to monitor eye pressure.
If you have glaucoma in both eyes, only one eye will be treated at a time. Laser surgery of each eye is done several days or weeks apart.
Studies show that laser surgery is very effective in reducing pressure in some patients. However, the results of surgery may disappear over time. Your eye doctor may suggest additional treatment.
Conventional surgery In conventional surgery, a new opening is made so that the fluid can leave the eye. (See the diagram on the next page.) Your eye doctor can suggest this treatment at any time. Conventional surgery is usually done when medications and laser surgery have failed to control eye pressure.
Conventional surgery is done in a clinic or in a hospital. Before surgery, you will be given medications to help you relax. Your eye doctor will put small injections around the eye to numb you. A small piece of tissue will be removed from the eye to create a new channel through which the fluid from the eye drains.
For several weeks after surgery, you should put a few drops in your eyes to avoid infection and inflammation. These drops are different from those used before surgery.
As with laser surgery, conventional surgery is done in one eye at a time. Generally the surgeries are done with a period of four to six weeks of difference between one and the other.
In some cases, the vision will not be as good as it was before the operation. Conventional surgery can cause side effects including cataracts, corneal problems, and inflammation or infection inside the eye. The accumulation of fluid in the back of the eye can cause some patients to see shadows. If you have any of these problems, tell your eye doctor to recommend a treatment plan.
