Glaucoma: A Rising Threat

Healthy Aging, Healthy Living
on August 8, 2012
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If all you know about glaucoma is that uncomfortable test your eye doc performs (or should) every time you get your vision checked, pay attention: This leading cause of blindness is on the rise. During the past decade, its prevalence has increased by 22 percent. Aging baby boomers are responsible, in part, for the increase. The risk for glaucoma rises around age 40, and once you hit your 60s you’re six times more likely to develop it than someone younger. (Other risk factors include being African American, Asian American or Hispanic; having a history of an eye injury; diabetes; and prolonged steroid use.)

Another reason to take glaucoma seriously: Many people don’t realize they have it until they start to lose their sight. An estimated 2.2 million Americans have glaucoma and more than 120,000 Americans are blind as a result of the disease, making glaucoma responsible for up to 12 percent of all cases of blindness in the U.S.

“Anyone can get glaucoma,” says ophthalmologist Dr. Kevin C. Greenidge of The Eye Institute of West Florida, a leading authority on glaucoma. Here’s what you need to know about this vision-robbing disease.

What is glaucoma?

There are three major types of glaucoma. The most common is called open angle glaucoma. Just as blood pressure can rise, threatening your heart, pressure in your eyes can rise, affecting your sight. Normally, a steady supply of clear fluid washes through our eyes, keeping them plump and nourished, and then is carried away through tiny drains. When the filters on these drains get clogged, fluid builds in the eyes, raising pressure—a phenomenon called intraocular pressure. Over time this pressure damages the optic nerve and causing your vision to deteriorate. Peripheral vision is the first to go, and you may not even realize it’s happening. “By the time peripheral vision is affected, your optic nerve has already sustained significant damage,” says Greenidge, spokesperson for Take On Glaucoma, a campaign designed to raise awareness of this eye disease.  Eventually, central vision is affected, too.

Angle-closure glaucoma is less common and comes on suddenly, causing hazy or blurred vision, rainbow-colored circles around bright lights, eye and head pain along with nausea or vomiting, and sudden loss of sight, according to the Glaucoma Research Foundation. It’s more common in far-sighted people with smaller eyes, says Greenidge. A rare form of glaucoma can affect newborns if the eye’s drainage canals haven’t fully developed.

Can glaucoma be reversed?

No. Once the optic nerve and vision have been damaged, that’s it—there’s no going back. That’s why you need to get checked for open-angle glaucoma starting in your 40s. During a procedure called tonometry, your doctor or eye care provider will apply anesthetic drops to your eyes and use a small instrument to measure pressure. Average pressure ranges from 12 to 22 millimeters of mercury; anything higher could signal glaucoma. Or not. “You can have pressure of 28 and not have glaucoma or you could have pressure of 14 and go blind,” says Greenidge. That’s why your provider should always check your optic nerve for structural damage during a dilated eye exam. “Half of patients with glaucoma can have normal pressure at a given time,” says Greenidge. Your provider should also test your peripheral vision to see how well your optic nerve is working, Greenidge suggests.

How is glaucoma treated?

The goal of treatment is to prevent or slow vision loss by bringing eye pressure down.

Eye drops—containing prostaglandin analogs, beta blockers, alpha agonists or carbonic anhydrase inhibitors—decrease the flow of fluid into the eyes, increase the flow of fluid through alternative drainage systems, or both. The drops, which are applied once or twice a day, can cause side effects. Among them are longer lashes, a shadow under the eyes, eye irritation and a change in eye color. “Light brown eyes may get darker,” Greenidge says. Laser therapy, which opens clogged eye drains, is another option. While it may eliminate the need for drops in some patients, it’s usually done to bolster the drops’ effectiveness. If pressure doesn’t respond to drops or laser therapy, surgery may be done to remove the damaged filter or place a stent in the eye’s filter, enabling fluid to flow out. During a more aggressive procedure, the eye surgeon may create a new drain in the eye.

RELATED: Glaucoma Basics

How often should I get screened for glaucoma?

“As long as people are seeing well, they believe everything is fine with their eyes,” says Greenidge. But half of people with vision damage caused by glaucoma don’t even know it, he adds. That’s why regular eye check-ups are critical. According to The Glaucoma Foundation, people under 40 need a thorough eye exam every three to four years. If you are 40 or older, or under 40 and have one risk factor for glaucoma, get screened every 18 months to two years. If you are 40 and older and have an additional risk factor besides age, get screened every year. To learn more about glaucoma, visit takeonglaucoma.com.