Glaucoma is one of the leading causes of blindness in the world. In the United States, approximately 2 million people are afflicted with the disease. If left untreated, glaucoma can cause progressive visual loss and blindness. This can usually be prevented if the glaucoma is detected and treated before significant damage occurs.
For more information visit: www.glaucoma.org
Glaucoma usually has no symptoms. In its early stages most people are unaware that they have the disease. Glaucoma, more than any other eye disease, requires early detection if treatment is to be successful.
The best way to prevent visual loss from glaucoma is through a medical eye examination every two to three years if you are over 40, and more frequently if you have risk factors for glaucoma (diabetes, family history of glaucoma, Afro-American heritage). At your examination, the eye pressure will be measured and the optic nerve examined. Other tests are ordered if there is a suspicion of glaucoma.
Once glaucoma is diagnosed, visual loss can usually be prevented or slowed with medical, laser or surgical treatment. Eye drops or pills are usually the first line of treatment, but if these are unsuccessful in halting glaucomatous damage, lasers or surgery may be recommended. Once vision is lost to glaucoma, it can never be regained.
WHAT IS GLAUCOMA?
Glaucoma is a disease where high pressure inside the eye damages the optic nerve. The optic nerve is the major nerve to the eye which delivers sight to the brain. Usually the higher the pressure, the more damage to the optic nerve.
Early detection and treatment by your ophthalmologist is essential to prevent optic nerve damage and blindness from glaucoma.
WHAT ARE THE CAUSES OF GLAUCOMA?
The front of the eye is filled with a clear liquid called aqueous humor. This liquid is produced behind the pupil of the eye, and exits the eye through drainage channels called the trabecular meshwork. If these drainage channels close or fail to function properly, the fluid pressure within the eye may increase, and optic nerve damage and visual loss may follow.
WHAT ARE THE DIFFERENT TYPES OF GLAUCOMA?
OPEN ANGLE GLAUCOMA: This is the most common type of glaucoma in the United States. It is caused by the drainage system of the eye failing to function properly creating a gradual pressure build up within the eye. This increased eye pressure damages the optic nerve, and is known as open angle glaucoma. Not all patients with elevated eye pressure develop optic nerve damage. Some patients have what is known as ocular hypertension, a condition where the patient's optic nerve can tolerate the elevated eye pressure. Open angle glaucoma is painless, and causes damage so gradually that patients are not aware of any visual loss until the optic nerve is severely damaged.
ANGLE CLOSURE GLAUCOMA: Occasionally the drainage area of the eye can suddenly become completely blocked. The eye pressure builds up rapidly, and optic nerve damage and visual loss can occur within a matter of hours. Whereas open angle glaucoma is usually asymptomatic, angle closure glaucoma is not. The symptoms of angle closure glaucoma include:
- Hazy vision
- Sudden severe eye pain
- Nausea and/or vomiting
- Seeing colored halos around lights
Should you experience these symptoms, you must call your doctor immediately. Unless treated, angle closure glaucoma can rapidly result in permanent blindness. Angle closure glaucoma can occur in any individual, although it is more common in people with Asian and Eskimo backgrounds.
LOW TENSION GLAUCOMA: Low or normal tension glaucoma is a rarer type of glaucoma in which the pressure inside the eye is in the normal range, but the optic nerve shows progressive damage.
CHRONIC ANGLE CLOSURE GLAUCOMA: This is a type of glaucoma where the drain of the eye gradually closes, and there are usually no symptoms.
HOW DO YOU KNOW IF YOU HAVE GLAUCOMA?
Routine eye examinations by your doctor are the best way to determine the presence of glaucoma. During the eye examination, your doctor will perform tonometry (measure your eye pressure) and ophthalmoscopy (evaluate for any optic nerve damage). In addition, gonioscopy (looking at the drainage area of the eye) and perimetry (testing the visual field, or peripheral vision of each eye) may be performed if glaucoma is suspected.
If glaucoma is suspected or determined to be present, these tests will need to be repeated at periodic intervals.
WHAT ARE THE RISK FACTORS FOR GLAUCOMA?
High eye pressure is just one of the risk factors for developing glaucoma. In addition to elevated eye pressure, other important risk factors include:
- Advanced age
- African heritage
- A family history of glaucoma
- A history of previous injury to the eye
- Use of steroid medications such as prednisone
Some patients are examined and found not have glaucoma, but are classified as glaucoma suspects. A glaucoma suspect means your risk of developing glaucoma is higher than the general population, and regular eye examinations are needed to detect any early signs of damage to the optic nerve.
WHAT IS THE TREATMENT OF GLAUCOMA?
There are several different ways to treat glaucoma including medications, lasers and surgery. Your ophthalmologist will determine which treatment is best to prevent further optic nerve damage and visual loss.
Glaucoma can often be controlled by taking one or several eye drops. Pills can also be effective, although they are not as commonly used as drops. Both the pills and eye drops decrease the pressure in the eye by increasing drainage from the eye or by decreasing the production of fluid within the eye.
For these medications to have a significant effect, it is imperative that they are taken regularly as prescribed.
Interestingly, eye medications can have side effects both in and around the eye, as well as in other parts of the body. If you experience any significant side effects that you think may be due to your eye medications, you should contact your ophthalmologist. In addition, you should let your other medical doctors know what eye medications you are taking.
Eye drops may have the following side effects:
- blurred vision
- dry mouth
- slow heart rate
- difficulty breathing
Pills used to control glaucoma may sometimes cause:
- numbness and tingling of the hands and feet
- loss of appetite
- kidney stones
Laser surgery to treat glaucoma is a safe and often very effective way to lower the eye pressure. The laser is usually used in one of two ways:
- in open angle glaucoma, the drainage area itself is treated to facilitate better drainage and lowered eye pressure. This is known as laser trabeculoplasty.
- in angle closure glaucoma, the laser forms an opening in the iris (the colored part of the eye), which improves the flow of fluid out of the drain. This is known as laser iridotomy.
When medications and/or laser treatment are ineffective in controlling glaucoma, surgery is needed. The most common type of surgery performed, a surgical trabeculectomy, creates an alternate path for the fluid to drain from the eye. This helps lower the eye pressure and prevents further optic nerve damage and visual loss. Your doctor will discuss this possibility with you when other options are not preventing progressive damage.
Serious complications from surgery can arise, but fortunately with modern micro-surgical techniques these are rare. Surgery is only recommended when the risk of visual loss from the glaucoma is greater than the surgical risks.
WHAT CAN YOU DO TO HELP?
Your ophthalmologist will suggest a treatment plan for glaucoma, but only you can make sure that these treatment recommendations are followed. Eye drops and pills need to be used precisely as prescribed, and you should never stop or change glaucoma medications without first consulting with your ophthalmologist.
HOW CAN VISUAL LOSS FROM GLAUCOMA BE PREVENTED?
Regular eye examinations are essential to detect glaucoma and help prevent permanent visual loss or blindness. You should have an examination every 2 years if you are age 40 or older. A medical eye examination should be performed at least every year if you have risk factors for glaucoma, which include:
- Age greater than 60
- A family history of glaucoma or ocular hypertension
- African heritage
- A history of serious eye injury
- The use of steroids such as prednisone