Glaucoma is called a “thief in the night” because it begins stealing vision before most people with the condition even notice it. It’s a leading cause of irreversible blindness, affecting millions — particularly older adults. Yet half of Americans with early-stage glaucoma don’t know they have it, according to the Centers for Disease Control and Prevention. 

Unfortunately, there’s no cure. That means spotting it early is crucial so that you can receive treatments to slow down progression and prevent more vision loss, says Landie Jean Baptiste, O.D. Dr. Jean Baptiste is an optometrist with Crystal Clear Eye Associates located inside America’s Best Contacts & Eyeglasses in Orlando, Florida.  

“Your eye doctor can spot very early signs of glaucoma and glaucoma risk, such as high pressure in your eyes, during a comprehensive eye exam,” Dr. Jean Baptiste says. “And the treatment is simple and very effective — daily eyedrops for most people.”  

Here’s what you need to know to protect your vision. 

What is glaucoma? 

Glaucoma is a group of eye diseases that damage the optic nerve. The optic nerve sends signals from the light-sensing part of your eyes (the retina) to visual-processing areas of your brain. It’s made up of more than 1 million fragile microscopic fibers.  
 
If you have glaucoma, higher-than-normal pressure in your eyes destroys these all-important fibers. Damage is usually subtle at first, affecting small areas of side vision for many people. You may not even realize it’s happening.  
 
“When I examine the eyes of a person with glaucoma, I can see the damage,” Dr. Jean Baptiste says. In instances of intermediate and advanced glaucoma, defects in the nerve fiber layer can be seen as an area of whitening in comparison to the rest of the retina. 

How common is glaucoma? 

An estimated 3 million Americans have glaucoma. Most — 2.7 million — have a type called primary open-angle glaucoma. Risk rises with age. Overall, open-angle glaucoma affects 1.2% of Americans in their late 50s. That figure rises to 4% for those in their late 70s and 7.8% for those 80 and up.  

Glaucoma is even more common and more of a vision threat in people of certain racial groups. Black Americans face a three to four times higher risk for open-angle glaucoma than non-Hispanic whites, and their risk for blindness is 15 times higher. Risk increases with age: By age 69, nearly 6% of Black Americans have glaucoma, increasing to 11% by age 80.  

Meanwhile, Asians, Hispanics, and Native Alaskans are at higher risk for another type, called closed-angle glaucoma. And people of Japanese descent face higher odds for normal-tension glaucoma.  

What causes glaucoma? 

The culprit is usually elevated pressure from fluid buildup caused by problems with the eyes’ drainage system. A clear fluid called aqueous humor fills the space between your cornea (the clear, rounded front of the eye) and your iris (the colored area of your eye).  

Aqueous humor provides nutrients and maintains the rounded shape of the front of your eyes. It’s constantly produced by your eyes, with excess flowing out through spongy tissue called the trabecular meshwork. But if the fluid cannot move out normally, it builds up inside your eyes and boosts pressure.  

In the various types of glaucoma, different factors interfere with the drainage system (read on for details). And for some people, optic nerve damage happens even when eye pressure is within the normal range. Experts are trying to understand why their optic nerve is particularly vulnerable.  

Glaucoma usually affects both eyes, though it may be more severe in one. 

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What does open-angle glaucoma do to your eyes?  

As mentioned above, open-angle glaucoma is the most common type, affecting 2.7 million Americans, according to the National Eye Institute. It’s full name is primary open-angle glaucoma (POAG). With POAG, little defects inside the trabecular meshwork slow down the flow of fluid. 

POAG typically has no symptoms until vision loss is advanced. You usually won’t feel pain or discomfort, according to the Glaucoma Research Foundation. But behind the scenes, optic nerve fibers are dying, and vision loss is progressing. It usually begins by subtly affecting your side, or peripheral vision. Without realizing it, you may start turning your head to see things off to the side more clearly. Over time, it also affects the central vision you use for reading, working on a computer, or driving.  

Eyedrops, laser treatments, and surgery are all effective treatments for POAG, Dr. Jean Baptiste says. “Eyedrops are the first-line treatment and lower eye pressure for most people,” she notes. “But some people will require laser treatments or surgery if eyedrops can’t lower pressure enough to slow and stop damage.” 

What are the different types of glaucoma? How are they treated? 

Open-angle glaucoma is the most common form of glaucoma, but there are other types:  

Angle-closure glaucoma

Also called closed-angle glaucoma, this problem happens at the eye’s “drainage angle,” where the iris and cornea meet. The edge of the iris blocks the normal flow of aqueous humor.  

This may be a slowly developing condition, called chronic angle-closure glaucoma. Or it can occur suddenly, creating a serious vision-threatening emergency known as acute angle-closure glaucoma. It requires immediate medical attention. Untreated, it can cause blindness in a few days, according to the National Eye Institute. 

Symptoms: As with open-angle glaucoma, chronic or “slow” angle-closure glaucoma may not have any symptoms early on. Acute angle-closure glaucoma symptoms include severe pain in and around the eye, headaches, red eyes, nausea, and blurred vision. It may happen in one or both eyes, and the symptoms last for hours. Get emergency help immediately.  

How it’s treated: Surgery or laser treatments are used to open up the blocked “angle” for better fluid drainage. 

Normal-tension glaucoma

Very similar to open-angle glaucoma, normal-tension glaucoma leads to vision loss in people who don’t have high eye pressure. Experts aren’t yet sure why it happens. But they do know that the risk is higher if you’re of Japanese descent, have a family history of normal-tension glaucoma, or have low blood pressure or an irregular heartbeat.  

Symptoms: You may not have any symptoms at first, but untreated normal-tension glaucoma progresses the same way as primary open-angle glaucoma. It affects side vision first and then your central vision. But some people with normal-tension glaucoma experience loss of central vision sooner than those with primary open-angle glaucoma.  

How it’s treated: Glaucoma treatments that lower eye pressure slow the progression of normal-tension glaucoma and can halt vision loss. 

Who’s at risk for glaucoma? 

These factors increase your risk for glaucoma: 

Age. Your odds for developing glaucoma increase with each passing year. People 60 and older are most likely to develop glaucoma, though risk rises beginning in your 40s.  

Race. A 2017 research review published in the journal Current Genetic Medicine Reports finds that Black Americans tend to develop primary open-angle glaucoma at a younger age, and they have a higher risk of blindness because of the disease. (Research to help understand the causes for these differences is underway.)  

Family history. You are four to nine times more likely to develop glaucoma if you have a family history.  

Eye problems and injuries. Eye trauma can inflame the eye or damage the drainage system. Surgeries for chronic eye conditions can also affect the anatomy of the drainage system.  

Eye anatomy. People who are highly nearsighted are more prone to developing glaucoma — moderate to severe myopia can more than double the odds. Experts aren’t completely sure why, but they suspect that myopia itself boosts the risk of damage to optic nerve fibers.  

Thin corneas are another risk factor, simply because eye-pressure measurements may be falsely low when taken through a thin cornea. In the past, that meant high pressure was missed in some people. But if your America’s Best optometrist suspects thin cornea, they can refer you to a specialist who would perform a quick, painless test called pachymetry that checks cornea thickness.  

Medical conditions. Having diabetes, high blood pressure, or heart disease can affect blood circulation and make you more prone to glaucoma.  

Long-term steroid use. The lengthy use of corticosteroids (such as cortisone, hydrocortisone, and prednisone) to treat certain types of arthritis, lupus, and other inflammatory conditions can increase eye pressure and lead to glaucoma. 

Can young people develop glaucoma? 

Yes. Glaucoma doesn’t only affect the eyes of older adults. People younger than 40 can develop glaucoma too. And about 1 in 10,000 babies are born with an inherited form of the disease called congenital glaucoma. It’s usually corrected with surgery to prevent vision loss. 

How is glaucoma diagnosed?  

Your eye doctor can spot early signs of glaucoma and of glaucoma risk during a comprehensive eye exam. That’s why most adults are encouraged to have a baseline screening at age 40, according to the American Academy of Ophthalmology and the Glaucoma Research Foundation. Start sooner if you have glaucoma risk factors.  

At your baseline screening, your doctor will make recommendations about how often you should be checked again. If you get the ‘all clear’, you’ll repeat the glaucoma check every two to three years until age 60, when screenings should take place once a year.  

Screening tests for glaucoma include tonometry and ophthalmoscopy. Tonometry measures pressure in the eye. Ophthalmoscopy scans the optic nerve for damage caused by glaucoma. Both of these screenings are part of your routine comprehensive eye exam. [link to eye exam HUB] 

Your eye doctor may do additional tests if results suggest a potential problem. These may include a visual field test (perimetry) to check for vision loss, a check of the angle where your cornea and iris meet (gonioscopy), and a measurement of cornea thickness (pachymetry). 

What is secondary glaucoma?  

A variety of health conditions can cause glaucoma too. This is called secondary glaucoma. Types include: 

Neovascular glaucoma

“Neovascular” means “new blood vessels.” This kind of glaucoma occurs when your eye produces extra blood vessels that block drainage. People with high blood pressure and/or diabetes are at higher risk.   

Symptoms: Vision loss, pain, and eye redness can be signs of neovascular glaucoma, though you may not have noticeable symptoms early on. A comprehensive eye exam will find early signs of vision-threatening, overgrown blood vessels in your eyes.  

How it’s treated: The standard treatments for neovascular glaucoma are eyedrops, laser treatments, and/or surgery to lower eye pressure, plus carefully managing underlying health conditions. In addition, your doctor will use injections and laser surgery to prevent blood vessels from continuing to grow. 

Pigmentary glaucoma

For people with an eye disorder called pigment dispersion syndrome (PDS), flakes of the colored pigment from your iris can block drainage. In one study, about 15% of people developed pigmentary glaucoma within 15 years of a PDS diagnosis. Lowering eye pressure is the usual treatment to prevent vision loss, but as of now there is no treatment for flaking pigment. 

Symptoms: Blurry vision and colored halos around lights are warning signs of PDS. Vision loss, signs of optic-nerve damage found during a comprehensive eye exam, and high eye pressure are all warning signs of pigmentary glaucoma. 

How it’s treated: Eyedrops are often prescribed first to lower eye pressure, with laser treatments or surgery if needed. You may need more frequent eye exams to ensure that eye pressure stays in the normal range and to catch optic nerve damage early.  

Exfoliative glaucoma

In people with an eye disorder called exfoliation syndrome, proteins build up inside the eye — including in the drainage system. Risk for exfoliative glaucoma can be inherited. People of Greek, Indian, Mediterranean, Russian, and Nordic descent may be at higher risk, according to the Glaucoma Research Foundation.  

Exfoliative glaucoma can develop more quickly than open-angle glaucoma and trigger higher eye pressures. This makes regular eye exams especially important if you’re at risk. Exfoliative glaucoma is treated with pressure-lowering medications, laser treatments, and surgery. 

Symptoms: Exfoliative glaucoma often strikes after age 60. Nerve damage and vision loss often have already begun. 

How it’s treated: Eyedrops are usually the first-line treatment for lowering eye pressure in exfoliative glaucoma. Laser therapy or surgery may be used if drops aren’t effective. 

Uveitic glaucoma

About 20% of people with uveitis, an eye disorder that causes inflammation and swelling, will also develop uveitic glaucoma. Experts think inflammation and scar tissue interfere with fluid drainage in the eye. But steroids that are sometimes used to treat inflammation in uveitis may contribute as well by raising eye pressure.  

Symptoms: Pain, blurry vision, headache, light sensitivity, and seeing colored halos around lights are among the symptoms. Signs of uveitic glaucoma include increased eye pressure, indications of optic nerve damage found during a comprehensive eye exam, or vision loss.  

How it’s treated: Pressure-lowering medications and surgery may be used to treat it. Laser treatments are often avoided because they may contribute to inflammation, according to the Glaucoma Research Foundation. Your eye doctor may also adjust the dose or stop your use of steroids too. 

Are there non-invasive treatments to help manage glaucoma? 

So far, there’s no cure for glaucoma. And damage to the optic nerve that’s already happened cannot be reversed, Dr. Jean Baptiste notes. “But you can slow down or prevent advanced vision loss with treatments that lower eye pressure,” she says.  

Prescription eyedrops that are used daily, for example, can decrease fluid buildup and associated eye pressure by limiting fluid production or increasing fluid discharge.  

In the U.S., “eyedrops are the first-line treatment for glaucoma,” Dr. Jean Baptiste says. “They are highly effective for most people.”  

A wide variety of eyedrops are available. If one isn’t working well or you have side effects, or your prescription costs more than you can afford, your eye doctor can prescribe another. Combination eyedrops are also available if you need more than one medication to control eye pressure. Some oral medications can also help by reducing fluid production. 

What other non-surgical glaucoma treatments are available? 

In March 2020, the Food and Drug Administration approved a dissolvable eye implant called Durysta™ that automatically releases a pressure-lowering drug for several months. 

There also are a number of minimally invasive laser treatments that help the eye drain more effectively, Dr. Jean Baptiste says.  

With selective laser trabeculoplasty, or SLT, for example, low-level laser light stimulates repair of the eye’s drainage tissue, improving fluid outflow in open-angle glaucoma. This may reduce pressure for months or even years. Your doctor may recommend SLT as an initial treatment instead of eyedrops or as an additional treatment if eyedrops don’t adequately lower eye pressure.  

A treatment called laser peripheral iridotomy may be used in angle-closure glaucoma to improve drainage by creating a tiny hole in the iris.  

For more advanced open-angle glaucoma, cyclophotocoagulation may be used to lower eye pressure by reducing the production of fluid in the eye. There are different types of cyclophotocoagulation laser treatments, some of which are non-invasive.  

And a laser procedure called scatter panretinal photocoagulation may be used in neovascular glaucoma to destroy abnormal blood vessels to reduce pressure in the eye. 

What surgical glaucoma treatments are available? 

It’s not easy to think about eye surgery, but Dr. Jean Baptiste notes that some patients truly benefit from more intensive treatments to bring down eye pressure and preserve your vision. She adds that the procedures are often short, out-patient procedures (meaning no overnight hospital stay is required), and that the success rate is very high. 

A trabeculectomy is a conventional “gold-standard” surgical procedure for open-angle glaucoma. The eye surgeon creates a tiny drainage flap in the white of the eye. Excess fluid goes into the flap and then drains into the body’s vascular system.  

For angle-closure glaucoma, an eye surgeon may perform a peripheral iridectomy to remove a small area of the iris, allowing fluid to drain more easily. 

Your eye surgeon may also recommend drainage implants. Here, a tiny drainage tube is placed in the eye. The tube sends fluid into a surgically created reservoir. The fluid is then absorbed into nearby blood vessels. 

As with any surgery, glaucoma surgeries carry risks, including the risk of infection. Other possible risks include: bleeding in the eye; a temporary increase in eye pressure; irritation; swelling; soreness; temporary blurriness; and dry eye. Be sure to discuss these with your eye care team ahead of time. Most of these after-effects will resolve quickly. 

After your procedure, you will be prescribed post-operative medications. Dr. Jean Baptiste says most patients need about one month to feel fully recovered post procedure.  

Additional reading 

4 Lesser-Known Facts About Glaucoma That Can Help Save Your Sight 

2 Common Vision Disorders You Should Know About Now  

Your Eye Exam Revealed an Eye Disease, Now What? 

Understanding Glaucoma: Spot It, Treat It, Prevent It