Glaucoma is the root cause of about 10 percent of total blindness in the United States, and many of the people affected are seniors (those over the age of 65). Additionally, the American Academy of Family Physicians notes that about 75 percent of those who are legally blind because of glaucoma are seniors. The overall number of Americans who have glaucoma is estimated to be around three million, but as the Glaucoma Research Foundation points out, it’s believed that half of people with glaucoma haven’t been diagnosed yet.
This doesn’t mean that as soon as you are diagnosed with glaucoma, you are definitely going to go blind. There are plenty of treatment options, and it’s important to know exactly what it is you’re dealing with so you can get ahead of the disease before severe vision loss and blindness occur. Let’s take a look at the different types of glaucoma, how they develop, and how you can prevent and treat it best.
What Is Glaucoma?
Glaucoma is the overarching term for a group of conditions that occur when your optic nerve is damaged, which in turn affects the quality of your vision. There is a buildup of pressure inside your eye, and that pressure damages the optic nerve—the main transmitter of information from your eye to your brain. The optic nerve rests at the back of your eyeball.
There are a couple different forms of glaucoma, based on how much pressure is built up in your eye and how the pressure accumulates in your eye. However, the main form of glaucoma is open-angle glaucoma, and around 90 percent of those who develop glaucoma have this form. From here on out, if we refer to glaucoma, we are generally talking about open-angle glaucoma, unless otherwise specified.
The Causes of Glaucoma
One of the root causes of glaucoma is optic nerve damage, which is caused by a buildup of pressure in the eye. The increased pressure is caused by fluid that naturally flows through the eye not being able to escape at its previous rate. According to the National Eye Institute, here’s how the optic nerve gets damaged in part to the fluid buildup:
- There’s a space toward the front of the eye called the anterior chamber that the fluid flows through. This fluid is used to cleanse other parts of the eye.
- The fluid leaves the chamber, passing through a meshy membrane, at the point where the cornea and iris—both toward the front of the eye—meet. Because the fluid is passing through the angle at which they meet, it’s considered “open.”
- But there comes a point where the fluid doesn’t flow through the angle at the speed it once did, which causes the buildup of fluid and then pressure in the eye.
- Sometimes, there is too much fluid produced by the eye, and it can’t push all of it through the angle. Other times, the angle becomes more blocked over time. In either situation, the buildup of pressure is the result, which causes glaucoma.
There are good diagrams that represent the flow of fluid through the eye here.
What Are The Symptoms Of Glaucoma?
The symptoms of glaucoma differ depending on which variation of glaucoma you have. But for angle-closure glaucoma, the symptoms are usually tough to spot because the disease develops so slowly—typically over the course of a couple of years. By the time the worst symptoms are taking place, the disease is usually pretty advanced and needs to be addressed immediately before blindness starts to settle in. Sometimes the symptoms are irreversible, which is why regular eye checkups are important.
While other versions of the disease and their symptoms (discussed in the next section) can onset rather quickly, we’ll look at symptoms of open-angle glaucoma in its advanced stages for now:
Peripheral visionThe first part of your vision that is usually affected once the effects of open-angle glaucoma start to set in is your peripheral vision—your side vision. You can develop blind spots or spotty vision in your peripheral vision, and eventually your peripheral vision can be all but absent. This causes tunnel vision.
Tunnel visionThis occurs once your peripheral vision has been damaged to the point where you can no longer see to the side, above, or below you without turning your head—you can only see what is in front of you. It’s almost like you’re looking through a narrow tube, and whatever is at the end of the tube is all you can see.
BlindnessThis occurs once glaucoma progresses to its final stage. The tunnel vision absolves into complete irreversible blindness.
Angle-Closure & Normal-Tension Cases
Other Forms Of Glaucoma
Though open-angle glaucoma takes up about 90 percent of glaucoma cases, there are other forms of the disease that occur in seniors and can develop quickly or in abnormal circumstances. (There’s a form of glaucoma called congenital glaucoma that occurs in young children that won’t be discussed at length.)
There have been cases where the angle where the iris and cornea meet is completely closed off, which doesn’t allow fluid to pass through and causes immediate, intense buildup of pressure and fluid in the eye. This condition can be caused by an inflamed iris or other outside damage to the eye, or it’s a condition that can develop very quickly. In any case, it needs to be addressed immediately, as symptoms of vision loss can move along rapidly.
Symptoms of angle-closure glaucoma include:
- Seeing rainbows around lights at night
- Intense blurred vision
- Sore eyes
After all this talk of abnormally high pressure in your eyes resulting in glaucoma, it turns out there are some cases where patients have normal eye pressure (IOP levels between 10 and 21 mm Hg) but still experience nerve damage that impacts their vision.
What also makes normal-tension glaucoma unique is that there usually are little to no symptoms of the disease until there has been significant enough nerve damage to where the disease is nearly irreversible. This is why it’s important to make frequent visits to the eye doctor, because they can diagnose the problem if they notice nerve damage despite having normal eye pressure. Then you can start the treatment process, which seeks to accomplish the same goals as the treatment for open-angle glaucoma: lowering eye pressure.
Even though your eye pressure levels may already be in a normal range, it’s important to keep them as low as possible while maintaining a healthy eye. This can be accomplished through medications and eye drops.
But again, the most important step in combatting normal-tension glaucoma is early detection.
Why Does It Happen?
To be clear, doctors aren’t fully clear on why normal-tension glaucoma occurs. The most common belief among researchers, however, is that those who develop normal-tension glaucoma have particularly sensitive optic nerves that render them more susceptible to damage despite normal eye pressure levels.
Even though there is so little known about normal-tension glaucoma, researchers have found common trends among those most at risk for the disease:
- It is more common among women than men.
- The condition occurs at higher rates among people of Japanese ancestry.
- Like open-angle glaucoma, it’s most common among older people, typically 60 and above.
- About a quarter of people who experience open-angle glaucoma also experience normal-tension glaucoma at some point.
- People with histories of heart disease and irregular heart beats are at a higher risk.
When you visit the eye doctor, they will ask you about your medical history. This is because there’s a chance having a history of migraines, Alzheimer’s disease, thyroid issues, or a previous history of eye issues can play a role in the development of normal-tension glaucoma.
How Can Glaucoma Affect Your Health?
Outside of vision loss, glaucoma can have direct, dire effects on your overall health. The American Foundation for the Blind noted several health issues that can stem from vision loss or total blindness, including:
Increased risk of fallsIt may sound obvious, but declining vision can increase your risk of falls or accidents, as your ability to judge depth and space are affected along with glaucoma. You may miss a step on the stairs, or you may hit the brakes a little too late because of declining vision. As you age, falls and accidents become more and more serious. Elderly persons’ bodies take longer to recover, which means longer hospital stays that can lead to increased rates of mortality and depression.
DepressionNot only can glaucoma affect the development of depression indirectly through falls and hospital stays, the AFB points out that more than 57 percent of the elderly with vision impairments are “at risk of mild or moderate depression” as opposed to 43 percent of the elderly without vision impairment.
ADLsVision loss affects your ability to complete activities of daily living (ADLs), which include bathing, preparing food for yourself, getting dressed, and getting out of bed. The sooner someone isn’t able to complete as many ADLs on their own, the sooner they may be need to live in a nursing home or assisted living facility, which can be both a financial and mental burden.
Who Is At A Greater Risk For Glaucoma?
Anyone, at any age, can develop glaucoma. That doesn’t mean all people have the same risk of developing it, though. There are certain conditions under which people are more likely to develop glaucoma. These include a range of certain demographics, history of the disease in your family, and other outside forces. Let’s look at some of the people at a greater risk of developing any form of glaucoma:
- The elderly: Specifically, those above the age of 60. The elderly are at a greater risk largely because of their exposure to potential eye trauma and other health maladies (which will be discussed) that can be indirectly to the development of glaucoma.
- Race: Certain races—like African-Americans and Hispanics/Latinos—run a greater risk of developing glaucoma than others for reasons that can’t quite be explained. It’s also been shown that these races are also at risk earlier in life, sometimes as early as 40.
- Previous eye injury: Trauma to the eye earlier in life can damage parts of your eye, and the effects don’t show up until years later. Corneas and irises could be shifted from previous trauma, causing a closure of the angle that needs to be open for fluid to flow through the eye.
- Corneal thickness: The thickness of your cornea can be a risk factor for developing glaucoma. In a study of more than 1,500 participants conducted in the early 2000s, researchers found that those with corneas thinner than 555 microns (about average) and high eye pressure were six times as likely to develop open-angle glaucoma than those with the same eye pressure and corneas thicker than 580 microns.
- Diabetes/heart problems: Heart health issues like low and high blood pressure and diabetes can play a role in increasing the chance of developing glaucoma. Knowing health issues like these can help in the treatment process, as well, so doctors can treat both, say, low blood pressure negatively affecting your optic nerve and the pressure inside your eye.
- Family history: If you have a family history of glaucoma, your chances of developing the disease are increased, as all the intangibles related to glaucoma (diabetes, heart problems, corneal thickness) can be passed down.
Testing For Glaucoma
We’ve heard a lot about eye pressure so far and how important that is to diagnosing and treating glaucoma. But how much pressure in the eye is too much? And if levels are normal, how do doctors check on the healthiness of the ever-important optic nerve? There are a few comprehensive tests eye doctors can do to help them fully understand what’s going on in and around your eye. These tests include:
TonometryThis measures the level of pressure inside your eye—the telltale sign of glaucoma. Normal levels of pressure range from 12 to 22 millimeters of Mercury (mm Hg) in your eye, so anything above that range signals that not enough fluid is escaping. This type of test is usually done in almost every eye doctor visit. The eye is numbed by eye drops, then a machine applies a puff of air to the eyeball that helps measure the pressure inside the eye.
GonioscopyThis test specifically measures the width of the angle between your iris and cornea—the important spot where fluid flows through the eye. It’s usually conducted after you’ve listed having symptoms of glaucoma (whether pressure levels are high or not) just to make sure which type of glaucoma it is: open-angle, angle-closure, or normal-tension.
OphthalmoscopyBecause there’s a chance you may have glaucoma despite normal levels of pressure, it’s also important doctors check on the health of your optic nerve. An ophthalmoscopy does that (in addition to analyzing other parts of the back of the eye). With this test, eye doctors dilate your pupils so they can see all the way to the back of your eye using a magnifying device.
There are other tests that look at your field of vision, quality of vision, thickness of the cornea, and other aspects of the eye that can all help explain pressure levels or help confirm a glaucoma diagnosis.
Open-angle glaucoma develops over time, meaning all the symptoms won’t just hit you at once and suddenly take away your vision. This allows for treatment plans to start years in advance to help combat the buildup of pressure in your eye before it does too much damage. But this also means that it’s important that you visit the eye doctor often so these issues can be caught before the disease has taken its toll and is irreversible.
Whether you have open-angle glaucoma or normal-tension glaucoma, they’re treated pretty similarly with the same end goal of reducing eye pressure. (Remember: closed-angle glaucoma needs to be addressed immediately, usually with surgery.) In order to reduce eye pressure, doctors usually prescribe several methods.
One of the popular forms of treatment to help relieve eye pressure are eye drops. These drops are made specifically to help reduce eye pressure as well as help the production of fluid and the flow of fluid through the eye. There are many classifications of glaucoma drops, including beta-blockers, prostaglandins, and parasympathomimetics. Your doctor will prescribe a certain type depending on what help your eye needs in flushing fluid through.
The Glaucoma Foundation described a method in which you can maximize the amount of eye drops absorbed into the eye rather than into the bloodstream:
“Close your eye for one to two minutes after administering the drops and press your index finger lightly against the inferior nasal corner of your eyelid to close the tear duct which drains into the nose.”
The eye drops take much longer to take effect and become diluted in the bloodstream, so you want to make sure the eye drops stay in your eye.
Advantages of eye drops are that they are cheap and only need to be applied once a day. There are side effects to glaucoma drops, though. These can include:
- Asthma attacks (which can turn deadly)
- Cardiovascular disease
Nevertheless, glaucoma drops have been proven to help decrease pressure in the eye—the first step in combating glaucoma.
Medications in pill form are usually prescribed to further help reduce eye pressure alongside eye drops (or if eye drops aren’t quite doing the full job). While eye drops may provide instant relief, medications take longer and work over months to help attack the parts of your eye that are contributing to glaucoma, whether it’s the amount of fluid your eye is creating and the rate it is (or isn’t) pushing through the angle or the damage to the optic nerve itself.
Doctors may also prescribe medications that assist with diabetes, high or low blood pressure, or other heart issues that may have been found to have contributed to the glaucoma in some way.
Medical marijuana has been proven to help reduce pressure in your eyes, and it has been used as a treatment for glaucoma for decades. An issue with medical marijuana, though, is that it only helps relieve pressure for three or four hours at a time, and it’s important to have round-the-clock relief for the symptoms of glaucoma to really subside.
This treatment can be taken in a range of ways, and how you intake medical marijuana plays into how long of a relief you can get. For instance, inhaling medical marijuana takes almost an immediate effect and helps relieve symptoms for several hours. Consuming the plant through food and drinks infused with THC—the leading chemical in marijuana used for medical purposes—can take 30 minute to an hour to take effect, but that effect lasts longer than inhaling it. Medical marijuana is also typically prescribed alongside eye drops, with the marijuana being used as more instant relief if eye drops start to wear off or have negative side effects.
Medical marijuana is legal in 29 of 50 states, so not everyone has this as a treatment option. Remember to check your state’s laws on medical marijuana.
Surgery is typically the last resort in combatting glaucoma (unless you have closed-angle glaucoma). Surgery happens when nothing else is working and something needs to be done inside the eye manually to help open the ever-important angle or help the fluid ducts to act properly again. There are two main options for surgery:
Often relatively quick and painless, laser surgery can make the meshy membrane that fluid flows through less clogged or affect how much fluid your eye is producing. You can usually go home the day of surgery, too. The largest issue with laser surgery is its long-term effects.
When medications and lasers won’t work, you may have to resort to traditional surgery, where a doctor manually goes into your eye and addresses the issue there. Eye surgeries related to glaucoma largely include opening new drainage areas or installing technology to help the eye drain more fluid. They’re also far more effective and usually help keep eye pressure levels low long after surgery.
The biggest preventative step you can take when it comes to fighting glaucoma is getting tested early and often. Andrew Iwach, a glaucoma specialist for the American Academy of Ophthalmology, said the following:
“Over the years, I’ve seen so many patients who had clear risk factors for glaucoma, but didn’t know of their risks until it was too late. It’s truly a shame to think how different their lives would be if they had only known of these risks and taken action to have a comprehensive eye exam sooner. It’s crucial that people remember that once vision is lost to glaucoma, it cannot be restored.”
Make sure you regularly visit the eye doctor—at least once a year, preferably twice or more if your vision is on the worse side, have a family history of the disease, or are over the age of 50.
Living a healthy lifestyle of eating properly and exercising can always indirectly help in the prevention of glaucoma. That’s because it can help reduce the risk of cardiovascular diseases, diabetes, and blood pressure issues that can play a role in the development of glaucoma.
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