By Walter Q. Wang, MD
Published by St Mary’s Newspaper
Glaucoma is a group of eye diseases that gradually steal sight without warning. In the early stages
of the disease, there may be no symptoms. Vision loss is caused by damage to the optic nerve. This
nerve acts like an electric cable with over a million wires. It is responsible for carrying images from
the eye to the brain. It was once thought that high pressure within the eye, also known as intraocular
pressure or IOP, is the main cause of this optic nerve damage. Although IOP is clearly a risk factor,
we now know that other factors must also be involved because even people with “normal” levels of
pressure can experience vision loss from glaucoma.
Glaucoma is the second leading cause of blindness in the world, according to the World Health
Organization. Over 4 million Americans have glaucoma but only half of those know they have it.
Approximately 120,000 are blind from glaucoma, accounting for 9% to 12% of all cases of blindness
in the U.S. About 2% of the population ages 40-50 and 8% over 70 have elevated IOP.
Glaucoma is a very misunderstood disease. Often, people don’t realize the severity or who is
affected. There are four key facts about glaucoma.
1. Glaucoma can cause blindness if it is left untreated. Unfortunately approximately 10% of people
with glaucoma who receive proper treatment still experience loss of vision.
2. Glaucoma is not curable, and vision lost cannot be regained. With medication and/or surgery, it
is possible to stop, slow down or halt further loss of vision. Since glaucoma is a chronic condition, it
must be monitored for life. Diagnosis by an ophthalmologist is the first step to preserving your vision.
3. Everyone is at risk for glaucoma. However, certain groups are at higher risk than others. Older
people are at a higher risk for glaucoma but young adults can get glaucoma, too.
4. There may be no symptoms to warn you. Usually, no pain is associated with increased
eye pressure. Vision loss begins with peripheral or side vision. You may compensate for this
unconsciously by turning your head to the side, and may not notice anything until significant vision
is lost. The best way to protect your sight from glaucoma is to get tested. If you have glaucoma,
treatment can begin immediately.
The following groups are at higher risk for developing glaucoma:
Glaucoma is the leading cause of blindness among African-Americans. It is six to eight times more
common in African-Americans than in Caucasians. African-Americans ages 45-65 are 14 to 17
times more likely to go blind from glaucoma than Caucasians with glaucoma in the same age group.
The most common form, Open Angle Glaucoma, accounts for 19% of all blindness among African-
Americans compared to 6% in Caucasians.
People Over 60
Glaucoma is much more common among older people. You are six times more likely to get
glaucoma if you are over 60 years old.
Family Members With Glaucoma
The most common type of glaucoma, primary open-angle glaucoma, is hereditary. If members of
your immediate family have glaucoma, you are at a much higher risk than the rest of the population.
Family history increases risk of glaucoma four to nine times.
Hispanics In Older Age Groups
Recent studies indicate that the risk for Hispanic populations is greater than those of predominantly
European ancestry, and that the risk increases among Hispanics over age 60.
People of Asian descent appear to be at some risk for angle-closure glaucoma. Angle-closure
glaucoma accounts for less than 10% of all diagnosed cases of glaucoma. Otherwise there is no
known increased risk in Asian populations.
Some evidence links steroid use to glaucoma. A study reported in the Journal of American Medical
Association, March 5, 1997, demonstrated a 40% increase in the incidence of ocular hypertension
and open-angle glaucoma in adults who require approximately 14 to 35 puffs of steroid inhaler to
Injury to the eye may cause secondary open-angle glaucoma. This type of glaucoma can occur
immediately after the injury or years later. Blunt injuries that “bruise” the eye (called blunt trauma)
or injuries that penetrate the eye can damage the eye’s drainage system, leading to traumatic
glaucoma. The most common cause is sports-related injuries such as baseball or boxing.
Other Risk Factors
Other possible risk factors include:
• High myopia (nearsightedness)
• Central corneal thickness less than 0.5 mm.
People at high risk for glaucoma should get a complete eye exam, including eye dilation, every one
or two years.
Sources: (1) Prevent Blindness America; (2) National Eye Health Program/National Institutes of Health; (3) American
Academy of Ophthalmology; (4) Racial differences in the cause-specific prevalence of blindness in east Baltimore. N
Engl J Med. 1991 Nov 14;325(20):1412-7; (5) Quigley, “Number of people with glaucoma worldwide,” 1996; (6) NEI,
Report of the Glaucoma Panel, Fall 1998
About the author: Walter Q. Wang, MD has completed his fellowship in Glaucoma at Harvard
Medical School. He is currently seeing patients at Eye Physicians of St Mary’s at Charlotte Hall, MD.
He volunteers for Georgetown University and The Congressional Glaucoma Caucus Foundation
screening glaucoma patients in the Washington metropolitan area.