Glaucoma is the name for several ocular conditions that cause an increased and destructive pressure inside the eye. This elevated pressure produces damage to the optic nerve and, subsequently, vision loss. A common cause of increased pressure is when channels that normally drain fluid from the eyes get blocked, resulting in pressure building up inside the eye.
The optic nerve is the main nerve that transmits vision from the eye to the brain. If the optic nerve is severely damaged or destroyed, the brain cannot receive visual input from the eyes and vision is lost, producing blindness.
Two types of glaucoma
Open-angle glaucoma is where the standard drainage system of eye fluids appears normal, but does not function well. Closed-angle glaucoma, not as common in the Western Hemisphere, occurs when the angle of the iris is too severe and causes a blockage or interference of eye fluid flow.
In rare cases glaucoma can develop suddenly, producing blurry vision and eye pain. This is a medical emergency and should be treated immediately.
Risk factors
- Family history of glaucoma
- Increasing age, especially over age 40
- Ethnicity (Black and Asian)
- Diabetes
- Heart disease
- High blood pressure (hypertension)
- Low thyroid gland function (hypothyroidism)
- History of eye trauma or surgery
- History of severe eye infection
- History of far-sightedness
- History of cataracts
- History of chronic eye inflammation
- Chronic use of steroid medications
African Americans older than age 40 have the highest risk of developing glaucoma. Persons of Asian ancestry have a moderately increased risk, too. A family history of glaucoma is a significant risk factor.
Although glaucoma can occur at any age, including childhood, it is the most common cause of vision loss in persons over age 60. Unfortunately, in many of these cases glaucoma could have been prevented.
Glaucoma produces a gradual decrease in vision, especially apparent at the periphery of a field of view. This usually happens in both eyes. Over time, the vision of an affected person becomes narrower and narrower, producing a condition referred to as “tunnel vision.” Glaucoma can, without treatment, progress over a few years to produce permanent blindness.
Accompanying the onset of glaucoma may also be blurred vision, severe headaches, halos around lights at night, reddening of the eyes and eye pain. Initially these symptoms may be mild, and the condition can be painless. As a result, glaucoma has been called “the sneaky thief of vision.”
Prevention
The goal is early detection and treatment with eye pressure control. If you are over 40 years of age or have a family history of glaucoma, schedule an eye examination with an eye specialist physician known as an ophthalmologist. The eye doctor will tell you how often, after this examination, you should have regular eye check-ups. With risk factors, usually the eye doctor will recommend regular eye examinations every one to two years.
How is glaucoma diagnosed?
Your eye doctor will perform a careful examination of your eyes. This eye examination will include a vision test and drops to dilate the pupils so the eye doctor can get a good view inside your eyes and a good view of your optic nerve.
The eye doctor will also do a particular test called tonometry that measures eye pressure. This pressure test is painless. The eye doctor may also take photographs of your inner eye to document any eye changes over time.
How is glaucoma treated?
The primary focus of glaucoma treatment is to reduce and normalize the pressure inside the eye. Pressure normalization can be accomplished by the use of topical medications (eye drops), oral medications, and by surgical intervention and correction.
Eye drops: The goal of eye drops is to either increase the draining of fluid inside the eye or reduce the amount of fluid produced by the eye, or both. The result is a reduction of the abnormally high and destructive pressure in the eye. Sometimes oral medications are used in conjunction with eye drops for optimal results. Some glaucoma medicines can affect the heart and lungs, so discuss this with your doctor.
Surgery: Both laser surgery and micro-surgery are used to treat and control glaucoma. The goal of all surgical interventions is to create openings that will increase fluid flow and drainage in the eye to reduce eye pressure. Sometimes drainage tubes can be surgically placed to re-establish normal eye fluid flow and pressure balance.
Remember, glaucoma can’t be prevented. Fortunately, if glaucoma is diagnosed early, it can effectively be treated and controlled, avoiding severe eye problems. Talk to your eye doctor to develop an examination schedule based on your risk factors, and stick to it. If you notice any vision changes, don’t wait – talk to your doctor immediately. Your eye health is in your hands.
Charles E. Crutchfield III, MD is a board-certified dermatologist and Clinical Professor of Dermatology at the University of Minnesota Medical School. He also has a private practice in Eagan, MN. He has been selected as one of the top 10 dermatologists in the United States by Black Enterprise magazine and one of the top 21 African American physicians in the U.S. by the Atlanta Post. Dr. Crutchfield is president of the Minnesota Association of Black Physicians.
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