Glaucoma is fairly common over the age of 35, affecting 2 of every 100 persons, is one of the leading causes of blindness and the single most common cause of blindness among African Americans. The best way to protect yourself from glaucoma is through early detection and treatment.
Facts about glaucoma
- Glaucoma causes damage to sight at an earlier age than many eye conditions.
- Blindness may develop rapidly.
- Glaucoma is more common among persons who are nearsighted or diabetic.
- Glaucoma is not contagious.
- Glaucoma is often symptomless.
What causes glaucoma?
There are several different types of glaucoma, but all types are caused by increased pressure within the eye that can destroy the optic nerve if not treated quickly.
A constant level of liquid called the aqueous humor is maintained in the inner chamber of the eye. Fluid flows into the eye from several structures, and fluid drains from the eye at a spongy outlet located at the angle where the cornea and sclera meet. If the outlet is clogged or if the drainage system is overwhelmed by too much liquid production, a buildup of fluid occurs and causes a pressure increase inside the eyeball, pressing on the optic nerve and its blood supply and potentially causing serious irreversible damage.
African Americans and Glaucoma
Glaucoma is one of the leading causes of blindness and the single most common cause of blindness among African-Americans. Due to this increased risk of glaucoma, people of African descent should see an ophthalmologist even if they have no signs of glaucoma or risk factors.
The symptoms of glaucoma vary depending on the specific type of glaucoma:
Chronic open-angle glaucoma
Chronic open-angle glaucoma, also known as chronic simple glaucoma or primary open-angle glaucoma, is the most common type of glaucoma. It primarily occurs in people over age 40 and is symptomless, often causing irreparable damage before it is discovered. This type of glaucoma may develop as a result of gradual aging, causing a decreased drainage capacity.
Congenital glaucoma is present at birth or shortly after birth. It is usually caused by a defect in the drainage system. Any infant who has symptoms of increased sensitivity to light or eyes that fill up with tears easily should be evaluated immediately to determine the nature of the problem and to prevent permanent damage.
Acute angle-closure glaucoma
Acute angle-closure glaucoma, also known as primary narrow-angle glaucoma or acute glaucoma, results from an immediate, complete blockage of the drainage area. The iris may press against the drain area causing sudden obstruction. Without drainage, fluid backs up and eye pressure increases rapidly. Rainbow-like halos or circles around lights, severe pain in the eyes or forehead, nausea, and blurred vision may occur. This type of glaucoma can occur suddenly at any age and is a true medical emergency; immediate professional care is needed to preserve sight. Blindness can result quickly in a day or two without treatment.
Secondary glaucoma occurs as the result of some other health problem of the entire body or of the eye. It may develop rapidly or slowly. If closure of the drainage system occurs rapidly, the symptoms will be similar to those described for acute angle-closure glaucoma. Immediate attention by an eye care professional is needed.
How is glaucoma diagnosed?
Prevention involves early detection through a comprehensive eye health examination, especially after age 35. Sometimes the level of pressure may be above normal, yet there are no symptoms, so an eye examination is the only way to discover the problem.
During a comprehensive eye examination an instrument called a tonometer is used to check the level of pressure in the eye. It is a simple, painless test that takes a fraction of a second to perform.
As part of your eye examination, your eye care professional can also determine the health of the optic nerve by examining the inside of the eye.
In addition, vision fields are performed to determine the presence of blind spots or shrinkage in the peripheral field of vision.
Treatment & Prevention
Damage to optic nerve fibers cannot be reversed. For that reason, sight can only be protected through early detection of the problem. Since glaucoma may grow worse without symptoms, periodic eye examinations for those over age 35 are imperative.
The goal of treatment is to prevent further damage and to preserve the highest possible level of vision. Glaucoma is treated by reducing the pressure within the eye. Medications, either pills or eye drops, are used to lower pressure either by causing better drainage of liquid or by decreasing liquid production. Treatment usually continues for life and must be taken regularly to effectively reduce eye pressure.
In some cases surgery may be recommended to correct drainage problems. The goal of surgery may be either to form a new drainage channel or open the old channel.
Since glaucoma cannot be prevented, the next best measure to protect sight is early detection and treatment, before optic nerve fibers have been destroyed. This can be accomplished only through regular comprehensive eye health examinations, because glaucoma often is symptomless. Everyone over the age of 35 should be tested for glaucoma every one to two years or whenever problems exist.