If you are thinking of using CBD oil for glaucoma, you should think again. THC-containing products are a far more effective treatment for the disease. You have probably heard of the benefits surrounding CBD, but what are the potential side effects you ought to be aware of? CBD is a chemical found in marijuana that is considered medicinal, and it has been advertised as a treatment for many issues, including glaucoma. Learn why CBD does not actually work well for eye treatment.
CBD and Glaucoma: Does It Help Reduce Eye Pressure?
However, when used in conjunction with other cannabinoids, CBD for glaucoma can work as an effective treatment.
There’s a lot of false information out there that suggests CBD alone is an effective way to treat the condition. This information can be dangerous to someone that actually suffers from the disorder.
In this article, we’ll be looking at the facts and helping you understand how certain cannabinoids can treat glaucoma.
What are the Effects of CBD on the Eyes?
On a normal healthy person, CBD has no known negative effects on the eyes however that isn’t the same for people with glaucoma as some studies suggest.
Using CBD alone in the form of an isolate can be detrimental if you have glaucoma. One study from Indiana University found evidence to suggest that CBD raises the pressure inside the eye . If this is true, CBD could worsen the primary underpinning of the disease.
The study was conducted on mice and found that CBD raised eye pressure by 18 percent. This lasted for up to four hours after the CBD was administered.
As you will know if you or someone close to you suffers from glaucoma, high eye pressure is a primary risk factor for people with the disease. High eye pressure can quicken the damage to the optic nerve at the back of the eye which could ultimately lead to blindness.
The best way to fight glaucoma is to lower eye pressure as much as possible. This will slow down any permanent damage that may be taking place. With this in mind, CBD alone isn’t recommended as a treatment for the disease.
If you were hoping to use CBD for glaucoma, do not fear, all hope is not lost. Other cannabinoids such as THC (tetrahydrocannabinol) have been found to lower eye pressure and have a positive effect on glaucoma.
When a true full-spectrum product is used to treat glaucoma CBD can actually benefit you. As we mentioned, CBD alone can be detrimental to the disease however when used in conjunction with THC it can have some positive effects.
Is THC Better for Glaucoma Than CBD?
THC as a singular cannabinoid certainly helps people with glaucoma more than CBD alone.
Numerous studies show that both delta 9-THC and delta 8-THC have a significant effect on optic nerve health. Evidence shows that THC not only reduces intraocular pressure but also helps to protect against neuron damage.
Research shows that both THC and CBD can protect against cell damage due to elevated levels of glutamate. CBD can indirectly help glaucoma as long as it is combined with other cannabinoids in a balanced true full-spectrum product.
Let’s take a look at how THC and CBD can positively impact eye health and be used to treat glaucoma.
THC Reduces Intraocular Pressure
Lowering eye pressure is an important factor in treating glaucoma. From as early as the 1970s, it has been common knowledge that THC lowers intraocular eye pressure. So, how does it work?
THC interacts with the receptors in the body’s endocannabinoid system. Studies show that THC reacts with receptors in the eye .
CB1 receptors have been found in the ciliary epithelium, the corneal epithelium, and the endothelium of the eye. It is believed that THC interacts with these receptors and as a result, intraocular pressure is lowered.
THC Decelerates Vision Loss
THC has been found to decelerate vision loss according to a study published in Experimental Eye Research .
The study tested the effects of THC on rats with retinitis pigmentosa — a genetic eye disease that leads to blindness. After a 90 day treatment, the rats that consumed the cannabinoid gained better scores on vision tests.
The THC rat group also acquired 40 percent more photoreceptors than the untreated control group. Those are some impressive results.
The potential that THC alone has to slow down blindness is staggering.
THC & CBD Support Optic Nerve Health
THC and CBD together have been found to support optic nerve health . People with glaucoma have an excess of glutamate — a major neurotransmitter in the eye.
In glaucoma sufferers, this neurotransmitter accumulates in the retinal region and damages cells, eventually leading to vision loss. This is called glutamate-induced neurotoxicity.
THC and CBD help protect against the condition, potentially preventing blindness and prolonging vision loss.
CBD Oil and Glaucoma
Most commercially available CBD oils will not help glaucoma, in fact, they could have an adverse effect. Even CBD oils labeled as full-spectrum aren’t going to cut it when it comes to this disease, as they simply contain too much CBD and not enough THC.
The best oil for glaucoma is a true full-spectrum THC-containing cannabis oil. Both delta 9-THC and delta 8-THC can be used to treat glaucoma with excellent results. Finding an oil that contains both cannabinoids is the best way to treat the disease.
Delta 9 and delta-8 THC are psychoactive so they will get you “high.” This is something to keep in mind if you are looking for cannabis to treat glaucoma because unfortunately, this side effect is unavoidable.
Research shows that delta 8-THC is slightly less psychoactive than delta 9 but you will still experience a “high.”
If you’re looking for a glaucoma treatment that helps but you are put off by the thought of being overly intoxicated, a delta 8-THC oil or tincture is worth trying.
If you can deal with the psychoactive effects of full-spectrum THC-containing cannabis oil, it will benefit the disease massively. Just remember not to operate any machinery or vehicles while medicated.
Is THC-Containing Cannabis Oil Legal?
Any cannabis oil that contains over 0.3% delta 9 THC is illegal under federal law, however, state law allows it depending on the state that you reside in.
Cannabis products, for the most part, are also banned across Europe and the UK, so make sure you know the law in your area.
Delta 8 THC is still technically legal under federal law, which means it is unbanned across the US. Regardless, make sure to check your state law if you are unsure of your local restrictions.
In most of Europe and the UK, any form of THC is banned by law, making delta 8 THC illegal as well.
Check the law in your country and region if you are planning on using THC for glaucoma. Cannabis is becoming more accepted as a medicine. Even in banned countries such as the UK, THC-containing products may be available on prescription from your doctor.
CBD vs. THC For Glaucoma
There are many benefits to using THC and CBD for glaucoma. Both cannabinoids have their place in treating the disease, but like any medication, there are some downsides.
If you have glaucoma and are considering using cannabis oil to treat it, you will have to weigh up the pros and cons. Doing this will help you understand whether this route is going to work for you.
- THC decelerates vision loss
- It reduces intraocular pressure
- Supports optic nerve health
- Analgesic qualities — can reduce pain
- Aids in the support of optic nerve health when used alongside other cannabinoids
- Vaso-relaxant — increases the level of ocular blood flow
- Anti-inflammatory — can reduce some side effects of glaucoma
- Analgesic qualities — can reduce pain
- Anti-nausea qualities — can help reduce the side effects of other glaucoma meds
- Is psychoactive — will get you “high” (can become an inconvenience)
- Only effective for three to four hours before another dose is needed
- High-quality oils and extracts are expensive
- Illegal in some states and across Europe
- When used alone it can raise intraocular pressure
- Must only be used alongside the psychoactive cannabinoid THC
How to Use CBD Oil for Glaucoma?
The best way to use CBD for glaucoma is in a true full-spectrum product that has a cannabinoid profile as close to the raw plant as possible. A delta 8 THC oil or tincture is another good option to consider.
You can use cannabis oil in a variety of ways to treat glaucoma. Full-spectrum oils are available in many forms. You will find pure oils, vape products, tinctures, capsules, gummies, and sprays.
You need to treat glaucoma 24 hours a day and unfortunately, the intraocular pressure-reducing qualities of THC don’t last long. You’ll need to medicate periodically throughout the day.
Studies from the National Eye Institute show that THC does lower IOP (intraocular eye pressure) by up to 30 percent. The downside is, IOP levels only stay this low for three to four hours.
If you’re going to use cannabis oil or another THC-containing product to treat glaucoma, you will need to medicate every three to four hours. This is great during the day but unless you plan on waking up every few hours at night, it is not so good.
Intraocular eye pressure levels increase during the night. This is mostly down to fluid distribution leading to choroidal vascular congestion when lying flat during sleep. This is a problem if you plan on using cannabis alone to treat glaucoma.
The answer is to use cannabis oil alongside other forms of glaucoma medication such as bimatoprost eye drops and/or acetazolamide pills.
Although you should continue using your prescription glaucoma meds, you may be able to reduce your intake and side effects by using cannabis oil alongside them.
How Much CBD Oil Should I Take for Glaucoma?
How much cannabis oil you take for glaucoma depends on a lot of factors.
Usually, one to two drops of cannabis oil under the tongue is sufficient for lowering intraocular eye pressure. Keep in mind, the strength of the oil you are using will ultimately affect the dosage.
If you are new to cannabis, start small with a 10 mg dose and increase once you know how you react to it. People react differently to THC so don’t be put off if you feel the need to increase or decrease your dose.
Speak to your local dispensary or get some advice on dosages for the specific oil you will be using.
No matter the strength or dosage you are taking it is important to remember to medicate every three to four hours to maintain low eye pressure.
Final Thoughts — Should You Use CBD for Glaucoma?
As you now know, CBD alone is not an effective treatment for glaucoma. The cannabinoid by itself can increase eye pressure which is a less than desirable effect if you have the disease.
If you have glaucoma, you should do your best to avoid CBD oils and stick to full-spectrum oils that are high in THC.
Glaucoma can’t be cured yet, but it can certainly be controlled. With the right treatment, the progression of vision loss can be slowed down dramatically and even stopped entirely.
People that suffer from glaucoma can lead perfectly normal lives with the right treatment. Cannabis can be a large part of that treatment and help you get back on the path to normality.
Cannabis oil or any other THC-containing products should not be used as a primary treatment for glaucoma. Any prescription medication should still be taken to reduce vision loss and prevent optic nerve damage.
Always check with your doctor before using cannabis alongside any existing medication.
References Used In This Article
- Miller, S., Daily, L., Leishman, E., Bradshaw, H., & Straiker, A. (2018). Δ9-Tetrahydrocannabinol and cannabidiol differentially regulate intraocular pressure. Investigative ophthalmology & visual science, 59(15), 5904-5911.
- Straiker, A. J., Maguire, G., Mackie, K., & Lindsey, J. (1999). Localization of cannabinoid CB1 receptors in the human anterior eye and retina. Investigative ophthalmology & visual science, 40(10), 2442-2448.
- Lax, P., Esquiva, G., Altavilla, C., & Cuenca, N. (2014). Neuroprotective effects of the cannabinoid agonist HU210 on retinal degeneration. Experimental Eye Research, 120, 175-185.
- Hampson, A. J., Grimaldi, M., Axelrod, J., & Wink, D. (1998). Cannabidiol and (−) Δ9-tetrahydrocannabinol are neuroprotective antioxidants. Proceedings of the National Academy of Sciences, 95(14), 8268-8273.
Livvy is a registered nurse (RN) and board-certified nurse midwife (CNM) in the state of New Jersey. After giving birth to her newborn daughter, Livvy stepped down from her full-time position at the Children’s Hospital of New Jersey. This gave her the opportunity to spend more time writing articles on all topics related to pregnancy and prenatal care.
The Potential Side Effects of CBD
Wendy Rose Gould is a lifestyle reporter with over a decade of experience covering health and wellness topics.
Verywell Mind articles are reviewed by board-certified physicians and mental healthcare professionals. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more.
Steven Gans, MD is board-certified in psychiatry and is an active supervisor, teacher, and mentor at Massachusetts General Hospital.
Verywell Mind content is rigorously reviewed by a team of qualified and experienced fact checkers. Fact checkers review articles for factual accuracy, relevance, and timeliness. We rely on the most current and reputable sources, which are cited in the text and listed at the bottom of each article. Content is fact checked after it has been edited and before publication. Learn more.
Karen Cilli is a fact-checker for Verywell Mind. She has an extensive background in research, with 33 years of experience as a reference librarian and educator.
Verywell / Alex Dos Diaz
Generally speaking, CBD is considered a safe substance when applied topically or taken orally. There are, however, some potential side effects to keep in mind when using this substance, the majority of which are mild.
Common Side Effects of CBD
The most comment side effects of CBD include drowsiness, gastrointestinal issues, dry mouth, reduced appetite, nausea, and interaction with other medications. Those are outlined in detail below.
Some common side effects when using CBD include drowsiness and sedation. This is also considered a benefit, but Dr. Jas Matharu-Daley, a physician and chief medical officer for a CBD brand, notes that the effects might be too strong if you’re also taking CBD with other sedating medications.
Some people may get diarrhea or liver problems [when using CBD]. This is dependent on the individual and their medical history, so monitoring is important,” says Dr. Matharu-Daley.
Also known as “cotton mouth,” CBD can potentially cause your mouth and eyes to feel very dry. Though this side effect is more likely to occur with THC, it can happen with CBD as well.
Can Interact With Other Medications
CBD might interfere with the other medications you take. Dr. Matharu-Daley says it’s important to talk to your doctor about whether CBD could affect your existing prescriptions.
In some cases, those who ingest CBD supplements might experience nausea, says Dr. Matharu-Daley. This depends on how sensitive the person is to CBD, as well as the amount they ingest.
Because CBD supplements come in so many different forms—such as oils, gummies, tinctures, and vapors—the amount that’s actually absorbed can vary drastically. This, combined with each person, will ultimately affect which (if any) CBD side effects you might experience.
What Is Cannabidiol (CBD)?
CBD—the abbreviation for cannabidiol, a substance that’s generally derived from the hemp plant—has skyrocketed in popularity over the last five years. In fact, according to research, “CBD” as a Google search term remained stable from 2004 to 2014 but has since ballooned by up to 605%.
CBD is one of the many chemical compounds that is found in the cannabis plant—referred to as cannabis sativa. There are two primary parts of the plant that humans use. One is THC, or Delta-9-Tetrahydrocannabinol, and the other is CBD. Though they’re from the same plant, THC and CBD are quite different from each other.
“CBD is not an intoxicating substance, whereas THC is a psychoactive that can get you high,” explains Dr. Jas Matharu-Daley, a physician and consultant for a brand that specializes in CBD production.
Are There Any Benefits Associated With Using CBD?
There are several reasons why someone might want to use CBD. The substance can be found in a multitude of products ranging from pain-relieving creams to edible tinctures to skincare. Research is still underway, but over the last few decades scientists have become more aware of how CBD might be beneficial when applied either topically or ingested.
“Since discovering the endocannabinoid system (ECS) in the body in the 1990s, CBD has been researched more extensively. The ECS is a central regulatory system restoring normal balance and homeostasis in a range of human physiologic systems throughout the body and brain and has cannabinoid receptors and chemicals in its function,” explains Dr. Matharu-Daley.
CBD benefits include the following:
- CBD can have positive impact on the brain. In fact, Dr. Matharu-Daley says that the substance is legally prescribed in a specific medication for certain severe forms of epilepsy in children.
- It has also been shown to have anti-inflammatory properties, which is why you often see CBD in topical products such as oils, creams, and lotions.
- Some research points to CBD’s ability to relieve stress and anxiety.
- It has been used as a nausea treatment in some countries.
- CBD may potentially reduce pain symptoms.
- It has antioxidant properties, which means it can help fight off free radical damages that leads to premature aging.
- Regarding skincare, CBD may help reduce excessive oil production in those with very oily skin types.
Ultimately, the primary reasons why people use CBD is because it tends to have calming, relaxing, pain-reducing effects. It has been used to alleviate joint pain and nerve pain, reduce anxiety and stress, treat insomnia, improve migraines, and address nausea.
CBD Is Still an Unregulated Substance
It’s important to point out that CBD is not regulated by the FDA and therefore dosages might not be accurate. It’s also difficult to know what an appropriate dose is the first time you try a new product.
“If the CBD is from a reputable source and one that has been inspected by a third-party independent lab, the content of CBD is more reliable,” notes Dr. Matharu-Daley. “The CBD should be organically grown, free of pesticides and heavy metals, and not sourced in food which can affect absorption. Generally, CBD is safe and side effects are few at low doses.”
A Word From Verywell
CBD is technically an unregulated substance in the United States and therefore it ought to be used with caution. This is especially important for those taking additional medications and/or those with ongoing medical issues. That said, preliminary research on CBD and its benefits are promising in relation to helping with mild to moderate health concerns and it is generally considered a safe substance. Health professionals do not consider CBD a cure-all for serious medical issues, including cancer.
As with any sort of supplement, we recommend speaking to your medical doctor about whether using CBD makes sense for you. Your doctor can also recommend certain products that align with your needs and help ensure you get the correct dosage.
CBD & the Eyes: Research & Can It Help You?
NVISION® content is medically reviewed by a licensed Ophthalmologist, Optometrist, Surgeon or Doctor. These vision experts ensure the content is fact-based and up-to-date.
We have strict sourcing guidelines and every page contains a full list of references for transparency.
CBD has become a touted treatment for various issues, including glaucoma. This is based on older medical studies and anecdotal reports that CBD oil, eye drops, and other forms of medical marijuana help to ease anxiety, eye strain, and eye pressure.
One of the first studies on medical marijuana for eye conditions involved glaucoma. This is a group of serious eye disorders associated with damage to the optic nerve, usually due to high fluid pressure in the eye, or intraocular pressure (IOP). This pressure must be lowered to prevent blindness. Further studies of medical marijuana have found that the drug does not actually lower pressure for long enough.
The United States Food and Drug Administration (FDA) has approved CBD for some very limited medical uses, and several states have legalized both medical and recreational use of marijuana, both THC and CBD.
Dispensaries recommend CBD for eye treatment, especially glaucoma. Medical research has found that medical marijuana does not lower eye pressure for more than three or four hours, which is not long enough to prevent damage to the optic nerve. Paradoxically, it may increase the risk of damage due to fluctuations in eye pressure over the course of the day.
In fact, a recent medical study found that THC, not CBD, lowered eye pressure. By itself, CBD raises IOP, and in combination with THC, it can prevent THC from lowering IOP. THC is the intoxicating, recreational chemical in marijuana, which can be addictive and cause problems with thinking or memory.
It is important for you to follow medical advice from your optometrist and ophthalmologist to manage all eye conditions, from dry eyes to glaucoma. Don’t attempt to self-treat any eye issue with CBD.
Table of Contents
Cannabidiol (CBD) & Your Eyes: High Intraocular Pressure Is Dangerous
Glaucoma is a group of related eye conditions involving damage to the retina and optic nerve that leads to vision loss, typically due to high fluid pressure inside the eyes. Symptoms tend to start slowly until enough of the optic nerve is damaged that the person develops tunnel vision or another form of lost vision. Regular eye exams can help to diagnose glaucoma or high ocular pressure, so an optometrist or ophthalmologist can monitor this progression and ensure you receive appropriate treatment if you begin to lose your sight.
Treating glaucoma starts with medicated eye drops that are designed to lower intraocular pressure. If these do not work, there are several approaches to surgery that can lower fluid pressure in the eyes and prevent vision loss.
There are side effects to all these options, so many people with glaucoma, or who are at risk for glaucoma, want to find alternatives. One proposed alternative is CBD oil, or the cannabidiol molecule derived from medical marijuana.
Using Medical Marijuana Like CBD for Your Eyes Does Not Work
As marijuana has become more popular and many states have legalized both medical and recreational uses for this drug, CBD oil is being promoted for a range of uses, including as a glaucoma treatment.
There are very few medical studies on the effectiveness of CBD or medical marijuana, although the United States Food and Drug Administration (FDA) has information on potentially beneficial uses for this approach to treatment. They have approved one CBD-based drug for two types of severe, rare epilepsy. Some forms of medical marijuana have been examined to treat eye conditions, especially glaucoma, but newer research suggests that CBD is not an effective treatment for your eyes.
Medical marijuana has been touted to generally ease physical and emotional pain, including nausea related to cancer treatment, chronic pain, general anxiety disorder, and other conditions. In the 1970s and 1980s, medical marijuana was studied as an eye treatment, particularly for serious conditions like cataracts and glaucoma, which can lead to blindness. The research found that marijuana could lower intraocular pressure for three or four hours at a time, and it was more effective at lowering pressure in the eyes than glaucoma drops.
However, the studies also found that these pressure-lowering effects would wear off after a certain amount of time, while the effects of glaucoma eye drop treatment lasted at least 12 hours. It is vital for eye health that treatment to manage intraocular pressure lasts for a long time and is consistent. When eye pressure rises and lowers several times throughout the day, damage to the optic nerve can get worse.
Medical Studies on CBD & the Eyes Suggests CBD Is a Dangerous Chemical
CBD in particular is receiving a lot of attention from the medical community and medical marijuana proponents. However, studies suggest that the CBD compound may make intraocular pressure higher, while THC (tetrahydrocannabinol), the chemical in marijuana associated with substance abuse and getting high, is responsible for lowering eye pressure.
A study conducted in 2018 found that THC and CBD regulate eye pressure differently. When they are separated from marijuana, they will have radically different effects.
The results of the 2018 study found that a single dose of THC drops lowered IOP by 28 percent for 8 hours in male mice, although humans with glaucoma need 24-hour pressure relief to reduce damage to the optic nerve. The study also found two interesting problems. First, CBD inhibited THC from lowering IOP. Second, the effects of THC on eye pressure were sex-dependent, with male mice receiving noticeably greater benefit from the treatment.
- Accelerated heartbeat, which can trigger anxiety or feel like anxiety.
- Decreased blood pressure overall, which can be harmful to the cardiovascular system.
- Reduced blood flow to several parts of the body, including the optic nerve, which can increase damage.
- Increased risk of lung cancer specifically from smoking or vaping marijuana products.
- Greater risk of addiction with any amount of marijuana treatment containing THC.
- Drowsiness, memory loss, and cognitive issues associated with abusing marijuana.
- Struggles to hold down a job or drive safely if drug-tested.
Most medical research suggests that CBD does not intoxicate you the same way THC does, but taking types of medical marijuana marketed as “high CBD” might mean there are traces of THC included in the substance. THC is addictive because it can change brain chemistry to make you feel relaxed, less anxious, sleepy, or even happy. The drug can also cause negative side effects like changes in mood, spikes in anxiety or paranoia, delusions, and trouble thinking or problem-solving.
Follow Your Eye Doctor’s Treatment Plan for Treating Eye Conditions
Some dispensaries hype CBD for the eyes aside from glaucoma treatment, suggesting that it can ease pain from surgery, reduce dry eye, and even alleviate eye strain. However, there are no medical studies to back up these claims. The changes to eye pressure due to CBD may lead to damage to your vision, even if you do not have glaucoma.
The only currently approved medical approach for glaucoma is regular eye exams to monitor the condition. Follow your eye doctor’s advice to manage this condition if you are diagnosed with it. This will likely mean eye drops first to prevent vision loss. It could also mean laser eye surgery, drainage devices, or other types of surgery to alleviate intraocular pressure and reduce damage to the optic nerve.
Glaucoma. (July 2020). National Eye Institute (NEI).
Cannabidiol (CBD) – What We Know and What We Don’t. (August 2018). Harvard Health Publishing, Harvard Medical School.
Is There a Risk of Blindness With CBD? (2018). United States Food and Drug Administration (FDA).
CBD Oil May Worsen Glaucoma. (February 2019). American Academy of Ophthalmology (AAO).
What Is Marijuana? (December 2019). National Institute on Drug Abuse (NIDA).
- Foods to Avoid if You Have Glaucoma
- Best Eye Supplements & Vitamins
- Can Nutrition or Diet Improve Vision?
- Beta-Carotene & Vision
- Omega-3s & Eyesight
- 7 Benefits of Castor Oil for Eyes & How to Use It
- Inflammatory Bowel Syndrome & Eye Issues
- Lutein & Zeaxanthin for Vision
- Vitamin C & Eyesight
Every NVISION® patient is unique. To determine the best treatment for you, please complete our simple form to schedule a consultation exam.