11 Questions About Glaucoma Answeredby Nancy Fitzgerald Health Writer
Little by little, glaucoma can make your world go dark—and you might not realize it until it’s too late. Glaucoma happens when fluid builds inside your eye, causing pressures to rise. Untreated, that pressure damages fibers in your optic nerve, which sends images from the outside world to your brain. Eventually, blind spots appear, first in your peripheral vision before spreading. The good news? Blindness is preventable. “There’s no cure, but there are good treatments,” says Eric Steffen, M.D., an ophthalmologist at Dartmouth-Hitchcock Medical Center in Lebanon, NH.
Who Gets Glaucoma?
Anyone can get glaucoma, but some people are at higher risk than others. “There are lots of genetic and racial components we don’t completely understand,” says Davinder Grover, M.D., an ophthalmologist at the University of Texas Southwestern Medical School in Austin. He says you’re most likely to develop glaucoma if you are over 40; are of African, Hispanic, or Asian heritage; have high blood pressure (HBP) or diabetes; take steroid medications; or if you’ve ever had an eye injury. According to the Glaucoma Foundation, if you have a sibling with glaucoma you're 10 times more likely to develop it yourself.
How Is Unhealthy Eye Pressure Detected?
Do you have one or more of the risk factors just mentioned? Then be sure to talk to your eye doctor, who’ll measure your eye pressure with a puff or blue-light test and by dilating your eyes to check your optic nerve. Just as important, be sure to schedule regular and complete vision exams. “Start in your twenties,” advises Dr. Steffen. “By your sixties, go yearly.” It’s important to monitor your eye pressure over time. That’s because quote-unquote normal pressures can vary between individuals, says Dr. Grover. “Every eye sets its own standard.”
What Causes Pressures to Build?
It has to do with how fluid enters and drains from the eyes. Glaucoma happens when eye pressure increases as the aqueous humor—the liquid that bathes and nourishes your eyeballs—gets out of balance. The culprit: your eye’s drainage angle, which is the little tube that lets new liquid in and old liquid out. When the drainage angle isn’t working properly, you can end up with one of the various types of glaucoma (because drainage can get screwed up in more ways than one).
Wait—There's More Than One Type of Glaucoma?
Yes. In fact, there are many types of this condition, even a congenital glaucoma that some babies—about one in 10,000 in the U.S.—are born with. However, there are two main kinds of glaucoma: open-angle glaucoma, which is the most common type, and closed-angle glaucoma, which is also sometimes referred to as narrow-angle glaucoma. If your eye doctor discovers unhealthy pressures in your eyes, you’ll likely be diagnosed with one of the two.
What Is Open-Angle Glaucoma?
This happens when your eye’s drainage angle—the duct that helps circulate the fluid in them—appears open but the drainage pathway does not function properly. Doctors then classify it with even more detail, labeling it as primary open-angle glaucoma when they’re not sure of its cause (although research shows it might be related to aging or genetics). With secondary open-angle glaucoma there’s a known or likely cause. It could be the result of an eye injury, perhaps, or diabetes, HBP, or various other health conditions. “With secondary glaucoma, we have an explanation for why you may have it,” says Dr. Grover.
How Is Open-Angle Treated?
It’s usually treated with eye drops. “They work by turning down the faucet, decreasing fluid, or by helping to drain it,” explains Dr. Steffen. Options include beta blockers that reduce fluid or prostaglandins that lower pressure by opening the drain. Selective laser trabeculoplasty (SLT) uses a laser to modify the drainage angle’s meshwork, improve flow of fluids, and drop pressure. (The catch: You may need a re-do every few years.) Micro-invasive glaucoma surgery (MIGS) is for mild to moderate glaucoma. Doctors make tiny incisions to create better drainage. A 2019 study found this technique to be low-risk and moderately effective.
What Is Closed-Angle Glaucoma?
Far less common, this occurs when your eye’s drainage meshwork is completely blocked—and, yep, doctors can also distinguish between primary and secondary cases based on cause. Primary closed-angle glaucoma is about the eye’s anatomy, explains Andrew Iwach, M.D., spokesperson for the American Academy of Ophthalmologists. “Eyes come in different shapes and sizes,” he says. When there’s not enough space between your iris—the colored part of your eye—and the cornea, your drainage angle may not have the room it needs to do its job. Secondary closed-angle glaucoma, though, can be due to other reasons, like chronic inflammation.
How Is Closed-Angle Treated?
This type of glaucoma can be treated with a combination of medication and procedures, such as an iridotomy, where your doctor makes a tiny hole in your iris using a laser or a traditional incision. “This creates more space for the drain,” explains Dr. Steffen, “and lets the fluid flow into the angle and out of the eye.” A drainage tube implant is another option. Rarely—and only for complicated cases—your doctor may place a tiny shunt directing excess fluid into a reservoir, where it’s absorbed into your blood vessels. “We create a new drainage system for the eye,” the doctor says.
What, Then, Is Acute Closed-Angle Glaucoma?
If you experience a sudden bout of blurry vision, eye pain, severe headache, and nausea from out of the blue, you may have acute closed-angle glaucoma. It’s super rare—but it is an emergency. So don’t hesitate. Call 911, or have someone drive you to the ER. It happens when your drainage angle becomes completely blocked. Left untreated, it can cause blindness within a few days or weeks. At the hospital, your doctor will first lower your eye pressure with an oral medication like acetazolamide or an eyedrop such as pilocarpine. Then, you’ll likely have an iridotomy.
Can Cataracts Lead to Glaucoma?
Glaucoma is the number-two leading cause of blindness in the U.S. What’s the first? Cataracts, a clouding of the eye’s lens that gradually leads to loss of vision. Two separate conditions—but they often happen at the same time. “As your lens gets cloudier and thicker, it can press on the drainage angle and may cause glaucoma,” explains Dr. Grover. “Sometimes, cataract surgery alone can help with glaucoma.” Or, your doctor may combine surgeries, replacing your eye’s cloudy lens with an artificial one and inserting a shunt that drains blocked fluid.
Can a Healthy Lifestyle Help Prevent Glaucoma?
It’s true that genetics can play a big role in who gets glaucoma and who doesn’t. But there’s still a lot you can do to save your eyesight before this condition strikes. “What’s good for the rest of your body is good for your eyes, too,” explains Dr. Steffen. “Follow a healthy diet, exercise, don’t smoke, make sure you get those regular eye exams.” Most of all, be positive—because modern medicine can help. “There are many effective ways to slow glaucoma down,” Dr. Steffen says. “It doesn’t have to be a sentence of blindness.”