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Does Cannabis Help With Glaucoma?

Updated July 25, 2022

Glaucoma is a condition that negatively affects your eyes, including your vision. As the use of medical marijuana rises, glaucoma has become one of the more common diseases whose symptoms can be alleviated by the use of cannabis. This trend continues today with cannabis proving itself effective at controlling glaucoma symptoms.

Understanding Glaucoma

Before you can explore how cannabis helps glaucoma, you need to understand the disease. As mentioned, glaucoma is a disease that affects the eyes and your vision. This is a degenerative condition that can progress very slowly, meaning that many patients do not detect it in the early years.

Research indicates that around 3 million Americans have glaucoma, with 4 percent of those glaucoma patients going blind eventually. Experts agree that many people with glaucoma do not know they have the condition since it is very hard to spot in its early stages.

Types of Glaucoma

There are two types of glaucoma, both of which can cause eyesight deterioration without treatment.

  1. Open-angle glaucoma is more common and is when the peripheral vision deteriorates.
  2. Acute angle-closure glaucoma comes with more severe symptoms, such as eye pain, vomiting, nausea, and headaches.

Causes and Treatments

Experts believe that the cause of glaucoma is either too much pressure within a person’s eyes or intraocular pressure. Because of that, traditional treatments work to reduce that intraocular pressure.

Traditional treatments usually include surgery, medications, and laser treatment. All of these treatments will focus on reducing the pressure in the lower eye, so the damage slows down. Most patients with glaucoma will have to use daily eye drops that are topical medications. Unfortunately, not everyone tolerates this treatment well, and it can be incredibly challenging for some people to get drops in their eyes successfully.

History of Cannabis for Glaucoma

The first report that marijuana was able to reduce intraocular pressure came in 1971. Since then, cannabis has earned a reputation as a natural remedy for glaucoma with minimal side effects.

One of the landmark cases for medical marijuana was about glaucoma. In 1974, Robert Randall was 26 years old and had poorly controlled glaucoma that was at an advanced stage. Randall usually saw halos around lights, but he noticed they went away after smoking marijuana. Randall risked jail time to bring this information to light and faced a federal criminal judge. He managed to convince the federal judge that his use of marijuana was necessary from a medical standpoint. This became a landmark case.

Cannabis Reduces Intraocular Pressure

Cannabis can help with treating glaucoma by reducing intraocular pressure. By reducing that pressure, cannabis helps to slow down the progress of glaucoma. Cannabis use will not benefit those who have already gone blind from glaucoma; it can just delay the progression.

Research as far back as 2004 indicates that some of the active ingredients in cannabis are responsible for lowering the intraocular pressure. Studies show that THC and marijuana reduce the intraocular pressure in normal individuals and those with glaucoma by between 60 and 65 percent. In one study, the mean reduction in intraocular pressure was around 25 percent. The effect applies to intravenous, oral, sublingual, and inhaled cannabis.

The studies also show that the reduction in intraocular pressure does not last long, only three to four hours. There is also a relationship between the dose-response with the extent of the reduction of pressure and quantity of marijuana. While taking higher doses is more effective at relieving the pressure, it does not improve the duration of the results.

Cannabis Has Neuroprotective Qualities

The neuroprotective properties of cannabis also play a role in its ability to help glaucoma. Recent research indicates that the neuroprotective properties of cannabis may help protect damage to a patient’s optic nerve. That would be a very different treatment method for glaucoma than most existing ones since the current methods rely on reducing intraocular pressure, not protecting the optic nerve.

Cannabis Relieves Other Symptoms of Glaucoma

Cannabis can also help patients with glaucoma control related symptoms.

Reducing Nausea

In 2008, researchers found that cannabis did a better job at suppressing chemotherapy-caused vomiting in cancer patients than the medications typically prescribed. Other research shows that the ability of cannabis to reduce nausea extends beyond chemo-related nausea and applies to nausea in general.

Reducing Vomiting

Thanks to its ability to reduce nausea, cannabis can also reduce vomiting. This makes sense since the two are usually connected.

Reducing Headaches

There is also plenty of evidence that cannabis can reduce the presence of headaches, which are one of the potential symptoms of glaucoma.

What About Marijuana Eye Drops?

There is some criticism associated with using cannabis to help glaucoma, including concerns about inhaling the smoke and the problems associated with that. This led to others wondering if marijuana eye drops could be the solution. This way, patients would not ingest cannabis through their lungs, avoiding those side effects.

Scientists have run studies that have patients ingest the THC from marijuana via eye drops, or via sublingual (underneath the tongue) or oral methods. These methods do successfully prevent lung problems linked to smoking cannabis. However, there may still be some other side effects.

There are also issues producing cannabis eye drops. While this seems like a logical solution, the fact that THC is not very soluble in water makes it hard to create the eye drops. The attempts so far do not have sufficiently high THC concentrations to make them effective.

Skeptics Remain

Despite the evidence that cannabis can help with glaucoma and its long-standing use for this condition, there are skeptics.

Concerns About Side Effects

Some argue that cannabis is not an ideal treatment for glaucoma because of the potential side effects of taking it, such as its psychoactive nature. Other than the psychoactive effects of cannabis, however, this concern is largely unfounded. Few people experience side effects when taking cannabis.

Even if there were side effects, they would typically be lesser than those associated with pharmaceutical drugs used in treating glaucoma symptoms. The minimal side effects would also be worth it for most glaucoma patients as there are not many other good ways to relieve the intraocular pressure.

There are also some concerns about the chemical compounds found in marijuana cigarettes. Experts found that these chemical compounds could cause lung damage in a similar way to tobacco cigarettes. You can get around this by rolling your own marijuana cigarettes or choosing a product that is all-natural. Research also indicates that in rare cases, chronic marijuana use could permanently impact brain function. The key here is that this side effect is very rare and requires chronic use.

Experts also believe that in addition to lowering the intraocular pressure, marijuana could lower blood pressure. While this is good for some patients, it would be an unwanted side effect for many. That is particularly true because lower blood pressure means the optic nerve receives less blood, which could further damage it.

Short-term Effects

They also argue that cannabis is not a feasible long-term solution since the positive effects will only last several hours. This is a valid point as it means that patients need to use cannabis consistently to reap the benefits. Most of the time, the relief in eye pressure will last three to four hours. It is not practical for people to smoke cannabis at these intervals, especially if they need to operate heavy machinery or work in a field that requires attention to detail.

However, there are methods of consuming cannabis that can increase the duration of the benefits and relief. Between the varying effects of different strains and options like edibles that are long-lasting, this criticism is easy to overcome.

The Official Stance

The official stance from the American Academy of Ophthalmology, the Canadian Ophthalmological Society, and the American Glaucoma Society is not to recommend cannabis or its derivatives like CBD as a treatment for any eye condition, including glaucoma. The organizations point out the lack of evidence and the inability to reduce the pressure 24/7 with cannabis. They also say that experts still need to conduct more research into how cannabis and its compounds affect glaucoma and eye pressure.

For the ideal treatment of glaucoma that saves the vision of a patient, you must control the eye pressure 24/7. That ideal pressure reduction for the average glaucoma patient is three to five mm Hg. That reduction in pressure would require ingesting ridiculously large quantities of THC, between 18 and 20 mg at six to eight times every day. This would interfere with regular activities and be cost-prohibitive in most cases.

Should You Use Cannabis for Glaucoma?

If you deal with glaucoma, you may want to try using cannabis to help prevent the condition from worsening and to treat your symptoms. You should only consider this as a treatment option if medical and recreational marijuana is legal in your jurisdiction and after getting the proper licensing.

If you do live somewhere where cannabis is legal, consider consulting your doctor about using cannabis to help your glaucoma. This would likely supplement your traditional treatments. You should always talk to your doctor before using cannabis to treat glaucoma since the plant can interact with certain medications. You do not want to render the medicines you currently take less effective.Before you use cannabis to help with glaucoma, you should also keep in mind that it would only provide temporary relief. Ingesting cannabis alone will not be enough to keep your intraocular pressure at safe levels unless you consumed large amounts that can hinder you from functioning normally. Because of this, cannabis to treat glaucoma should supplement your other glaucoma treatment, not replace it.

Consider Its Psychoactive Properties

When deciding if you should use cannabis to help with your glaucoma, you also need to consider your lifestyle and the psychoactive properties of the plant. If you have a detail-oriented job or operate heavy machinery, including cars, you would not be able to use your medical cannabis at or right before work, since it would pose a risk.

Even if you do not have a detail-oriented job, drive, or operate heavy machinery, you should confirm how you react to cannabis before incorporating it into your glaucoma treatment. Start by trying it on a weekend or holiday so you can gauge your reaction since this varies by person.

How to Use Cannabis for Glaucoma

Although medical experts and glaucoma patients have recommended cannabis to treat the disease for well over a decade, there are still no clear guidelines on using cannabis in this way.

CBD for Glaucoma

Given the challenges associated with using cannabis for glaucoma, such as side effects, some wonder whether CBD could be a better option. After all, CBD or cannabidiol provides relief for a range of conditions. Unfortunately, researchers still need to conduct more studies on the potential of CBD for glaucoma treatment. One study actually showed that it could worsen glaucoma by increasing the intraocular pressure, but this was a single study.

If experts could create a CBD-based solution to relieve the symptoms of glaucoma and prevent its spread, this would be ideal. This is because CBD is non-psychoactive, so it would not interfere with a patient’s daily life by making them high. CBD is also legal in more states than cannabis is, which would make it easier for patients to get treatment. For now, those with glaucoma need to wait for more research.


Experts tout cannabis for its ability to help with glaucoma treatment, but there is still some debate about its effectiveness. Cannabis can help prevent the spread of glaucoma by reducing the intraocular pressure that causes the condition. The caveat is that cannabis will only last for several hours in a row, and you need to control your intraocular pressure 24/7 to prevent worsening your vision.

Experts have more planned research to look into the impact of cannabis on glaucoma. Hopefully, they will achieve more concrete results and be able to develop a cannabis-based solution that lasts longer than four hours and does not come with side effects.

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