Glaucoma
Keeping the pressure off
The thought of being without sight is unfathomable for most people. Nevertheless, blindness can affect anyone, with glaucoma being one of its leading causes. About 2% of all Americans over age 40 have glaucoma.
Glaucoma involves increased eye pressure. When the pressure in the eye rises, it damages the optic nerve. Though there are many forms of glaucoma, the main types are open-angle, closed-angle, and secondary glaucoma.
You can take precautions to avoid glaucoma, and there are effective treatments. The important thing to remember is to take glaucoma seriously. Once the optic nerve is damaged, the loss is permanent.
Pronunciation
glaw-KOH-muh
Abbreviation of Condition
- COAG (Chronic open-angle glaucoma)
- NAG (Narrow-angle glaucoma)
Detailed Description
Glaucoma in all its forms is the No. 1 cause of blindness among African-Americans and the No. 3 cause among Caucasians. If you have Asian or Eskimo ancestry, you are also at higher risk. At least three million cases of diagnosed glaucoma exist, and it's estimated that at least one million more remain undiagnosed. If left untreated, glaucoma can lead to permanent blindness.
Glaucoma comes in many different types. The names identify the different causes of the same condition. The three most common:
- Open-angle: pressure gradually rises in the eye, slowly causing damage to the optic nerve.
- Closed-angle: (narrow-angle) increased pressure brings on a sudden painful attack.
- Secondary: an outside force, such as injury or infection, causes an increase in eye pressure.
Open-angle glaucoma is the most common -- about 90% of cases. Painless, with few or no symptoms, it's found most commonly in people over age 35 and in those with diabetes and nearsightedness. It has also been found to run in families. When fluids drain too slowly from the anterior chamber of the eye -- the space between the cornea and the iris -- pressure eventually builds. As this happens, the optic nerve is damaged, with vision loss. This type of glaucoma usually affects both eyes.
Closed-angle glaucoma is less common than open-angle glaucoma but much more painful. Fluid buildup behind the pupil quickly increases eye pressure. Anything that causes the pupil to dilate and reduce the angle of the drainage system can trigger an attack, which can include vision loss, headache, eye pain, nausea, and vomiting. Vision impairments can include blurred vision and seeing halos around lights. Unlike open-angle glaucoma, closed-angle glaucoma usually only affects one eye at a time.
Secondary glaucoma occurs when injury, infection, or another eye disorder slows the drainage of the aqueous humor (eye fluid). It can also follow enlarged cataracts, or long-term use of cortisone-like drugs.
A less common form of glaucoma is called normal (or low) tension. In this type, even though the eye pressure is within "normal" range, the optic nerve is injured.
Glaucoma can also be congenital, when the ducts responsible for fluid drainage fail to form completely.
You should seek medical assistance when dealing with any type of glaucoma in order to get the right treatment. All glaucoma, if not treated, can lead to permanent blindness.
How Common Is Glaucoma?
Glaucoma is the second leading cause of blindness in the United States and accounts for 12% of all new cases of blindness in North America. Glaucoma appears to affect men and women equally before age 45. Between ages 45 and 64, it's more common in men; over age 64, it affects more women.
What You Can Expect
Eye damage can take a long period of time, as with open-angle glaucoma, or happen quickly, as with closed-angle conditions.
Established Causes
Fluid fails to drain from the front of the eye (open-angle glaucoma) or from behind the pupil (closed-angle glaucoma), causing increased pressure in the eye. This damages the optic nerve.
Risk Factors
The risk factors for chronic open-angle and acute closed-angle glaucoma include:
- Family history of glaucoma
- Diabetes
- Asian or Eskimo ancestry
- Nearsightedness
- Excessive alcohol consumption
- Age: More prevalent in all people over age 60; more prevalent in African-Americans over age 40
The risk factors for secondary glaucoma include the following:
- Diabetes
- Other eye disorders (e.g., uveitis, tumors, cataracts)
- Use of certain drugs (e.g., steroids)
- Eye trauma
Risk factors are traits or behaviors that may make you statistically more likely than others in the general population to have a certain condition. They are not necessarily "causes" of the condition.
Symptoms
Open-angle glaucoma
Both eyes usually have symptoms, often after the condition has been developing for some time. They include the following:
- Loss of peripheral vision
- Mild aching in the eyes
- Occasional headaches
- Blurred vision
- Seeing halos around lights
- Difficulty adapting to darkness
Eventually, tunnel vision (an extreme narrowing of vision) may develop. At this stage you can only see that which is directly in front of you, while side vision is gone.
Closed-angle glaucoma
Usually originates in one eye, and occurs suddenly and dramatically. Within a few hours symptoms become apparent:
- Swelling and pain in one eye
- Pressure over the eye
- Swollen eyelids and redness of eyes
- Moderate pupil dilation with no reaction to light
- Slight decrease in vision
- Colored halos appear around lights
- Severe headaches
- Tearing
- Nausea and vomiting
Secondary glaucoma
Depending on the condition's cause, symptoms will vary. Usual symptoms are:
- Headache
- Seeing halos around lights
- Blurred vision
Congenital or infantile glaucoma
A baby born with this disorder may have an enlarged cornea and tearing eye.
How Glaucoma Is Diagnosed
Your physician will check for glaucoma during eye tests. Your pupils may be dilated. This allows the ophthalmologist to see more of the inside of the eye. (Of note: dilating an eye affected with closed-angle glaucoma may worsen the condition.)
Your ophthalmologist may also conduct the following tests to confirm glaucoma:
- Tonometry: a brief, painless burst of air measures the fluid pressure of your eye. It is important to note that eyes with normal pressure may rarely develop symptoms of glaucoma and that individuals with very high pressure may have no symptoms.
- Slit-lamp exam: the doctor examines the front of the eye, including the lens, iris, and cornea.
- Gonioscopy: distinguishes between chronic open-angle and acute closed-angle glaucoma.
- Visual image analysis: detects changes in the optic nerve before noticeable loss of vision. Evaluates glaucoma that occurs with normal or low eyeball pressure.
- Ophthalmoscopy: allows the ophthalmologist to view the deepest region of the eye. Cupping and shrinkage of the optic nerve are visible in chronic open-angle glaucoma, and can also occur in the late stages of chronic closed-angle glaucoma.
- Visual field tests: show field of vision -- central and/or peripheral (side) -- and allow doctors to pinpoint the extent of vision loss.
Goals of Treatment
The idea behind treatment is to return the eye's pressure to normal. Closed-angle glaucoma is sometimes treated preventively-- if one eye has had an acute attack, a physician may suggest that the other eye be treated with surgery, thereby avoiding a buildup of intraocular pressure.
The primary goals of glaucoma treatment:
- Gradually reduce and normalize the eye pressure, preventing permanent damage to the optic nerve.
- In acute cases, quickly reduce and normalize eye pressure, stabilizing the eye so corrective surgery may be performed.
- In secondary glaucoma, diagnose and treat the underlying cause of the rising pressure.
Treatment Options
Medicated eye drops and surgery (laser or traditional) are effective treatments. For those with open-angle glaucoma, a beta-blocker prescription is usually the first line of defense. In the case of closed-angle glaucoma, eye drops, internal medications, pain relievers, and anti-nausea medication can help to reduce the immediate attack, but the ultimate treatment is usually surgery.
Drug Therapy
Drugs most commonly prescribed
For open-angle glaucoma:
- Pilocarpine (Isopto-Carpine)
- Carbachol (Isopto-Carbachol)
- Epinephrine (Epifrin)
- Betaxolol (Betoptic)
- Carteolol (Ocupress)
- Timolol (Timoptic)
- Latanoprost (Xalatan)
- Dorzolamide (Trusopt)
For attacks of closed-angle glaucoma (a medical emergency):
- Acetazolamide (Diamox) (oral or intravenous)
- Glycerol
- Isosorbide
- Mannitol (intravenous)
- Pilocarpine or timolol (ophthalmic)
After breaking the attack, surgical drainage may be necessary.
Surgery
The goal of treating glaucoma with surgery is to allow better eye fluid drainage. This can be achieved in a number of ways:
- Iridotomy: involves making a small hole in the iris to allow drainage. The most common procedure for treating most narrow-angle glaucoma.
- Trabeculectomy: an exit route, or bypass, is made in the part of the eye that normally drains fluid.
- Implantation: a drainage valve or tube is implanted.
- Ablation or surgical removal: removal of the area of the eye that produces aqueous humor.
Trabeculectomy and iridotomy procedures are performed either traditionally or with lasers.
Even if the condition is only present in one eye, treating both eyes via medication and/or surgery is often advised to avoid recurrent attacks of narrow-angle glaucoma.
Appropriate Healthcare Settings
Outpatient (including surgical procedures)
Healthcare Professionals Who May Be Involved in Treatment
Medical professionals involved in treating glaucoma include the following:
- Ophthalmologists
- Optometrists
Managing Glaucoma Treatment
Annual testing and open communication with your eye care professional are the keys to treating glaucoma. Be sure to report any change in vision to your doctor.
Monitoring the Condition
Routine eye exams are extremely important in maintaining your vision-- if you're under 45, that means every four years, or every two years for those 45 and older. If you have risk factors, exams should be every two years or yearly, respectively.
Possible Complications
Blindness, if left untreated.
Considerations for Women
Pregnancy
Internal medications containing acetazolamide should be avoided by women during the first three months of pregnancy.
Considerations for Children and Adolescents
Infantile glaucoma (congenital glaucoma) is rare. Its symptoms are similar to open-angle glaucoma.
Considerations for Older People
Glaucoma occurs much more frequently in older people; you should have an exam for it every year or two, depending on your risk factors.
Supplements
- Vitamin C: helps preserve the collagen in the eyes' drainage tubes -- the ones that malfunction in glaucoma. Vitamin C may also help reduce fluid pressure in the eye.
Herbs
- Berries: eating dark-colored berries may help prevent or slow the progression of glaucoma. Blueberries, blackberries, bilberries, cranberries, huckleberries, raspberries, grapes, raisins, plums, and prunes all contain anthocyanosides, antioxidants with a special affinity for the eye. [1] Eat more of these fruits, or take an anthocyanoside supplement. Naturopaths -- physicians who avoid drugs in favor of nondrug treatments -- recommend 80 to 160 mg three times a day of a standardized bilberry extract containing 25% anthocyanosides.
Last updated October 1999.
Source
[1] Duke, James. The Green Pharmacy. Emmaus, PA: Rodale Press, 1997.
Preventing Glaucoma
Prevention comes in the form of routine examinations performed by your eye doctor. By measuring the eye's pressure, it is possible to detect the beginning signs of glaucoma and treat it accordingly. The Glaucoma Research Foundation recommends screening at age 35, age 40, and every two to three years thereafter until age 60, when you should be screened every year or two.
In the case of eye damage, an accident, or infection, physicians should be aware of the danger of raised eye pressure. Prompt treatment and attention is crucial.
Self-Care Measures
- If you smoke, stop. Smoking increases glaucoma risk. Also, stay away from secondhand smoke -- it too damages the eyes' delicate blood vessels.
- Try to eliminate environmental factors that provoke allergic responses.
- Use caffeine cautiously. Caffeine -- found in coffee, tea, colas, and some over-the-counter drugs -- can raise blood pressure and fluid pressure in the eye. Though there are conflicting reports, some studies show a correlation between caffeine consumption and glaucoma risk. If you have a family history of glaucoma, it's best to err on the side of caution and limit your caffeine intake.
- Cut down on protein and margarine. Some research suggests that a diet high in protein (found in meats and dairy products) and high in trans-fatty acid (found in margarine) can increase the risk of glaucoma.
Websites & Organizations
American Academy of Ophthalmology
P.O. Box 7424
San Francisco, CA 94120-7424
Phone: 415-561-8500
American Optometric Association
243 Lindbergh Boulevard
St. Louis, MO 63141
Phone: 314-991-4100
Email: AmOptCCC@aol.com
Eye Care
1319 F Street NW
Washington, DC. 20004
Glaucoma Foundation
33 Maiden Lane
New York, NY 10038
Phone: 800-452-8266
Email: glaucomafdn@mindspring.com
MayoClinic
National Eye Institute
2020 Vision Place
Bethesda, MD 20892-3655
Phone: 301-496-5248
Northwest Vision Institute
1370 116th Avenue NE, Suite 110
Bellevue, WA. 98004
Phone: 425-450-2020
Fax: 425-688-0620
Prevent Blindness America
500 East Remington Road
Schaumburg, IL 60173
Phone: 800-331-2020 or 847-843-2020
Steen-Hall Eye Institute
2611 Greenwood Road
Shreveport, LA 71103
Phone: 318-631-2020 or 800-326-9938
Sources for This Article
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