The increased pressure in your eye, called intraocular pressure, can damage your optic nerve, which sends images to your brain. If the damage worsens, glaucoma can cause permanent vision loss or even total blindness within a few years.

Most people with glaucoma have no early symptoms or pain. Visit your eye doctor regularly so they can diagnose and treat glaucoma before you have long-term vision loss.

If you lose vision, it can’t be brought back. But lowering eye pressure can help you keep the sight you have. Most people with glaucoma who follow their treatment plan and have regular eye exams are able to keep their vision.

Glaucoma Causes

The fluid inside your eye, called aqueous humor, usually flows out of your eye through a mesh-like channel. If this channel gets blocked, the liquid builds up. Sometimes, experts don’t know what causes this blockage. But it can be inherited, meaning it’s passed from parents to children.

Less-common causes of glaucoma include a blunt or chemical injury to your eye, severe eye infection, blocked blood vessels inside your eye, and inflammatory conditions. It’s rare, but eye surgery to correct another condition can sometimes bring it on. It usually affects both eyes, but it may be worse in one than the other.

Glaucoma Risk Factors

It mostly affects adults over 40, but young adults, children, and even infants can have it. African Americans tend to get it more often, when they’re younger, and with more vision loss.

You’re more likely to get it if you:

• Are of African American, Irish, Russian, Japanese, Hispanic, Inuit, or Scandinavian descent
• Are over 40
• Have a family history of glaucoma
• Have poor vision
• Have diabetes
• Take certain steroid medications such as prednisone
• Have had an injury to your eye or eyes
• Have corneas that are thinner than usual
• Have high blood pressure, heart disease, diabetes, or sickle cell anemia
• Have high eye pressure
• Are nearsighted or farsighted

Types of Glaucoma

There are two main kinds:

Open-angle glaucoma. This is the most common type. Your doctor may also call it wide-angle glaucoma. The drain structure in your eye (called the trabecular meshwork) looks fine, but fluid doesn’t flow out like it should.

Angle-closure glaucoma. This is more common in Asia. You may also hear it called acute or chronic angle-closure or narrow-angle glaucoma. Your eye doesn’t drain like it should because the drain space between your iris and cornea becomes too narrow. This can cause a sudden buildup of pressure in your eye. It’s also linked to farsightedness and cataracts, a clouding of the lens inside your eye.

Less common types of glaucoma include:

Secondary glaucoma. This is when another condition, like cataracts or diabetes, causes added pressure in your eye.

Normal-tension glaucoma. This is when you have blind spots in your vision or your optic nerve is damaged even though your eye pressure is within the average range. Some experts say it’s a form of open-angle glaucoma.

Pigmentary glaucoma. With this form, tiny bits of pigment from your iris, the colored part of your eye, get into the fluid inside your eye and clog the drainage canals.

Glaucoma Symptoms

Most people with open-angle glaucoma don’t have symptoms. If symptoms do develop, it’s usually late in the disease. That’s why glaucoma is often called the “sneak thief of vision.” The main sign is usually a loss of side, or peripheral, vision.

Symptoms of angle-closure glaucoma usually come on faster and are more obvious. Damage can happen quickly. If you have any of these symptoms, get medical care right away:

• Seeing halos around lights
• Vision loss
• Redness in your eye
• Eye that looks hazy (particularly in infants)
• Upset stomach or vomiting
• Eye pain

Glaucoma Diagnosis

Glaucoma tests are painless and don’t take long. Your eye doctor will test your vision. They’ll use drops to widen (dilate) your pupils and examine your eyes.

They’ll check your optic nerve for signs of glaucoma. They may take photographs so they can spot changes at your next visit. They’ll do a test called tonometry to check your eye pressure. They may also do a visual field test to see if you’ve lost peripheral vision.

Glaucoma Treatment

Your doctor may use prescription eye drops, oral medications, laser surgery, or microsurgery to lower pressure in your eye.

Eye drops. These either lower the creation of fluid in your eye or increase its flow out, lowering eye pressure. Side effects include allergies, redness, stinging, blurred vision, and irritated eyes. Some glaucoma drugs may affect your heart and lungs. Be sure to tell your doctor about any other medications you’re taking or are allergic to.

Oral medication. Your doctor might also prescribe medication for you to take by mouth, such as a beta-blocker or a carbonic anhydrase inhibitor. These drugs can improve drainage or slow the creation of fluid in your eye.

Laser surgery. This procedure can slightly raise the flow of fluid from your eye if you have open-angle glaucoma. It can stop fluid blockage if you have angle-closure glaucoma. Procedures include:

• Trabeculoplasty. This opens the drainage area.
• Iridotomy. This makes a tiny hole in your iris to let fluid flow more freely.
• Cyclophotocoagulation. This treats areas of the middle layer of your eye to lower fluid production.

Microsurgery. In a procedure called a trabeculectomy, your doctor creates a new channel to drain the fluid and ease eye pressure. This form of surgery may need to be done more than once. Your doctor might implant a tube to help drain fluid. This surgery can cause temporary or permanent vision loss, as well as bleeding or infection.

Open-angle glaucoma is most often treated with combinations of eye drops, laser trabeculoplasty, and microsurgery. Doctors tend to start with medications, but early laser surgery or microsurgery could work better for some people.

Infant or congenital glaucoma — meaning you are born with it — is usually treated with surgery because the cause is a problem with your drainage system.

Glaucoma Prevention

You can’t prevent glaucoma. But if you find it early, you can lower your risk of eye damage. These steps may help protect your vision:

• Have regular eye exams. The sooner your doctor spots the signs of glaucoma, the sooner you can start treatment. If you’re over age 40 and have a family history of the disease, get a complete eye exam from an eye doctor every 1 to 2 years. If you have health problems like diabetes or are at risk of other eye diseases, you may need to go more often.
• Learn your family history. Ask your relatives whether any of them have been diagnosed with glaucoma.
• Follow your doctor’s instructions. If they find that you have high eye pressure, they might give you eye drops to prevent glaucoma.
• Exercise. Moderate activity like walking or jogging at least three times a week might help lower eye pressure.
• Protect your eyes. Use protective eyewear when playing sports or working on home improvement projects.