CBD Oil for Glaucoma: How Does It Work?
According to the Glaucoma Research Foundation, an estimated three million Americans suffer from the eye condition and half of them are unaware of their issue. It is the leading cause of blindness in the United States and 10% of people with the condition experience vision loss – even when they get the proper treatment.
In the U.S. alone, glaucoma accounts for up to 12% of all cases of blindness.
It is especially prevalent amongst African-Americans, who are up to eight times more likely to become blind from glaucoma than Caucasians. Despite all of the above, a 2002 Prevent Blindness America Survey uncovered a shocking fact: 30% of people had never heard of glaucoma!
Moreover, 50% of those surveyed had heard of the condition but were unsure of what it was. Let’s try to shed some light on this condition and see whether or not CBD oil for glaucoma may be a long-term treatment option.
What Is Glaucoma?
Also known as the ‘silent thief of sight’, glaucoma is an eye disease that results in elevations in fluid pressure in the eye. If you fail to treat it in time, it can cause loss of vision and even permanent blindness.
In primary glaucoma, the cause is largely unknown. In secondary glaucoma, however, the condition has a known cause, such as diabetes, inflammation, cataract, or a tumor.
Risk factors of glaucoma include:
- Old age
- Illnesses or conditions such as hypothyroidism
- Eye surgery
- Eye injuries
- Ethnic background (African-Americans, Hispanics, and East Asians are at greater risk than Caucasians)
Also, did you know that there are several types of glaucoma?
This type of glaucoma affects up to 95% of people with the condition. Initially, there are no symptoms and it occurs because the drainage canals of the eyes get clogged over time, leading to increased pressure buildup. The intraocular pressure – or IOP, as it’s called – increases because the right amount of fluid cannot properly drain out of the eye.
If you have open-angle glaucoma, the drainage canal entrances are working properly, but there will be a clog deep inside the canals. The condition develops slowly and you may not experience any loss of vision for years. If you can catch it early, medication can help treat the condition.
Also called narrow-angle or acute glaucoma, this condition is relatively rare and involves intraocular pressure that rises rapidly and without warning. The drainage canals become blocked because the iris is not as wide as it is in a healthy eye. The iris’ outer edge bunches up over the canals when the pupil enlarges too fast or too much (such as when you suddenly enter a dark room from a bright outside area).
Symptoms of angle-closure glaucoma include eye pain, nausea, headaches, and blurred vision. You are more likely to notice angle-closure glaucoma than its open-angle equivalent, and in most cases treatment involves surgery to remove some of the outer edges of the iris.
Other Types of Glaucoma
The two glaucoma types we have mentioned above comprise the vast majority of cases. There are however some rare forms of the condition, which include:
- Normal-Tension Glaucoma
- Secondary Glaucoma
- Pseudoexfoliative Glaucoma
- Pigmentary Glaucoma
- Congenital Glaucoma
- Traumatic Glaucoma
- Irido Corneal Endothelial Syndrome (ICE)
- Neovascular Glaucoma
What Are the Most Common Glaucoma Treatments?
Several forms of glaucoma treatment involve surgery in an attempt to fix the issue. When it comes to open-angle glaucoma, eye drops are the most commonly prescribed option.
There are various types of medicated eye drops that are specifically formulated to treat glaucoma, including:
- Cholinergic agents
- Carbonic anhydrase inhibitors
- Prostaglandin Analogues
These medications tend to work in different ways. For example, beta-blockers like Timolol work by decreasing the production of fluid that leads to increased IOP. Prostaglandin analogs, such as Xalatan and Travatan, increase the outflow of fluid from the eye, though these medications come with an array of side effects. For instance, those taking beta-blockers may experience the following:
- Reduced pulse rate
- Low blood pressure
- Shortness of breath
- A decrease in the amount of blood pumped out by the heart
- Decrease in libido
CBD for Glaucoma: Can It Work?
Please note that at the time of writing, there is no permanent cure for glaucoma. Nor have there been any large-scale clinical trials reporting on the specific effects of CBD for glaucoma.
However, a large number of studies have shown cannabis as a whole – even those strains high in THC – to be a viable and highly effective treatment. A 1971 study by Hepler and Frank, for example, discovered that cannabis lowered intraocular pressure (IOP) by up to 30%.
The problem with using cannabis, though, is that you have to consume it every few hours because the effects don’t last very long.
In other words, you have to be high for most of the day. While this might seem like a pleasant way to live for some, it is not practical for most people. Also, while cannabis has a low addiction rate, using it six or more times a day would greatly increase the risk of developing a dependence on the plant.
This is where CBD comes in. Cannabidiol is one of marijuana’s non-intoxicating cannabinoids, and some research has suggested that it is just as useful as THC and other psychoactive compounds for the treatment of glaucoma.
The endocannabinoid system (ECS) was only discovered in 1992, but research since then has uncovered some pretty exciting things. In fact, the ECS has been called ‘the future of medicine’ by some experts.
Glaucoma and the Endocannabinoid System
The ECS is one of the human body’s most important physiological systems. It has an impact on almost every aspect of health, including pain modulation, immune response, and inflammation. Regarding glaucoma, cannabinoid receptors are involved in the ocular tissues which regulate IOP.
Researchers are hoping to create medications from cannabinoids such as CBD that can target these ocular tissues in an effort to reduce IOP and eventually protect retinal cells from the permanent damage that leads to blindness.
Incredibly, there has been evidence for over four decades that CBD could help treat glaucoma. The study, published in the International Journal of Pharmacology and Biopharmacology in 1979, analyzed the effects of CBD on 16 patients with open-angle glaucoma.
After taking CBD, the patients experienced a reduction in blood pressure and an increase in heart rate. Ultimately, this resulted in a decrease in IOP behind the eyes – the direct cause of glaucoma. Moreover, it was observed that the effects of CBD lasted longer in patients with hypertension.
The issue now with existing cannabis-based glaucoma treatment is bioavailability.
Although topical application via eyedrops works best, it still means that only 5% of an administered dose reaches the target.
This is why some people have resorted to vaping CBD (a potent means of administration for glaucoma) or taking it as an oil to ensure that more of the active compound is actually put to use.
It is important to note, though, not to use too much CBD oil as a 2006 study by Tomida et al. found that CBD doses of above 40 mg can actually increase IOP in the eye. In the majority of instances, glaucoma sufferers have found that doses between 10-20 mg have been effective. (Though please note that this is NOT a recommended dosage or valid medical treatment option).
Final Thoughts on CBD for Glaucoma
When administered correctly, CBD could potentially lower IOP and protect the eye’s retinal cells.
Moreover, the vaso-relaxant properties of CBD could increase ocular blood flow and its anti-inflammatory properties have the potential to provide relief not just for glaucoma, but also for other inflammatory eye conditions as well.
One of the biggest problems with existing glaucoma medications (such as those listed above) is the litany of side effects. In most instances, this is far less of an issue when using cannabis. While the THC in marijuana results in a psychoactive ‘high’, CBD is non-intoxicating. Therefore, you can use it regularly, safe in the knowledge that it won’t impact your judgment and side effects are minimal.
According to the Glaucoma Research Foundation, an estimated 3 million Americans have the eye condition . If you are one of them explore CBD.
Glaucoma, Marijuana & CBD: Facts & Myths
Table of Contents
- The Search for Lower Intraocular Pressure
- Can Medical Marijuana or CBD Help Glaucoma Symptoms?
- The Science of Marijuana’s Impact on Glaucoma
- Medical Studies
- Eye Doctors Understand
Glaucoma involves high intraocular pressure and damage to the optic nerve. The most common type of glaucoma, open-angle, is a chronic and progressive disease that can be tough to manage. As medical marijuana becomes more popular, more people are interested in the suggestion that marijuana or CBD oil can help this eye condition. (Learn More)
Medical professionals agree that no form of medical marijuana, especially CBD products, helps to manage glaucoma symptoms. In fact, some types of medical marijuana can make symptoms worse and cause further eye damage. (Learn More)
The few medical studies conducted on marijuana and intraocular pressure found that THC, not CBD, temporarily lowers IOP. But this result does not last long enough to make it a good medical treatment. And marijuana can be addictive. (Learn More)
Further medical studies have shown that CBD in medical marijuana can slightly raise intraocular pressure, and marijuana decreases blood flow. Both of these things can further damage the optic nerve. (Learn More)
The best way to treat glaucoma is to follow your eye doctor’s treatment plan. (Learn More)
Glaucoma & Marijuana: The Search for Lower Intraocular Pressure
The term glaucoma covers several eye diseases that involve high fluid pressure and damage to the ocular nerve, leading to vision loss.
Open-angle glaucoma is the most common type. This is a progressive, chronic disease that leads to tunnel vision and eventual blindness if it is not treated. Other types of glaucoma may develop suddenly, and some even constitute a medical emergency and require immediate surgery.
Most people who develop glaucoma will not notice symptoms. An optometrist or ophthalmologist will diagnose high fluid pressure during your regular eye exam and conduct further tests to measure any potential vision loss. Then, your eye doctor will recommend medical treatment like eye drops or surgery to reduce your vision loss. While you cannot recover lost vision, you can slow the progression of open-angle glaucoma.
Eye specialists continually search for better treatments to slow the progression of chronic forms of glaucoma. The first study examining marijuana’s impact on glaucoma occurred in 1971. It found a 30 percent overall decrease in eye pressure among participants who smoked a marijuana cigarette an hour before undergoing an eye exam.
Since then, this and related studies have been used to promote now-legal medical marijuana like cannabidiol (CBD) to treat glaucoma. However, this treatment is not recommended by medical professionals.
Can Medical Marijuana or CBD Help Glaucoma Symptoms?
Medical professionals agree that marijuana, including CBD, is not an effective treatment for glaucoma. This means that, even if medical marijuana is legal in your state, your optometrist or ophthalmologist will not prescribe it as a medical treatment for this condition.
First, glaucoma must be managed 24 hours a day, and no form of marijuana is a practical treatment for ongoing management of any condition. The drug’s effects only last a few hours, while many chronic conditions require medication that lasts at least half the day.
Additionally, there is little medical research into how marijuana affects glaucoma. The research that does exist suggests that the drug does not help eye pressure for long, and it can be detrimental to the condition over time.
Finally, it is well known that marijuana is an addictive substance. While it may not be more harmful than alcohol, it is a drug that causes intoxication, impaired judgment, and changes in brain chemistry and structure that impact the rest of your life.
The Science of Marijuana’s Impact on Glaucoma
While there were some studies in the 1970s and 1980s that found marijuana could lower intraocular pressure, the real association between the drug and glaucoma treatment occurred due to a landmark medical marijuana court case in 1974.
A man named Robert Randall, who was 26 years old with high intraocular pressure and poorly treated glaucoma (unusual for his age) reported that the halos he saw around lights, which were a symptom of his eye condition, decreased when he smoked marijuana. He began to grow his own pot so he would have access to “medicine” that seemed to work for him. Soon, he faced federal criminal charges for growing the illegal plant, but he was able to persuade the federal judge that he needed marijuana as a medical treatment.
California became the first state to legalize marijuana in any form, in 1996. Glaucoma treatment was cited as one of the potential conditions that medical marijuana could help.
Although CBD has more recently been associated with medical marijuana, the chemical that works on intraocular pressure is tetrahydrocannabinol (THC). This chemical has been shown to lower intraocular pressure by 60 to 65 percent in anyone, including people who have glaucoma. One study found that, over the course of marijuana’s primary effects on the body, IOP lowered 25 percent overall. This could seem to help glaucoma patients, but it is not a long-term solution due how THC is metabolized.
THC’s peak effects in the body last for three to four hours. For any medical marijuana treatment to be effective for glaucoma, you would need to take a dose several times a day. Not only is this disruptive to work, school, or a regular daily routine, it also means you will be consistently intoxicated, which can be very dangerous. Marijuana, especially types high in THC, is addictive.
Short-term effects of marijuana include:
- Altered senses, like seeing brighter colors.
- Altered sense of time.
- Changes in mood.
- Impaired body movement.
- Difficulty thinking clearly.
- Problems with memory.
- Trouble solving problems.
- Hallucinations, delusions, and even psychosis, when used at very high doses.
- Paranoia or anxiety.
When used on a long-term basis, marijuana changes your brain’s development and alters structures in the brain associated with the reward system. Some medical studies have found that consistent, long-term abuse of this drug lowers intelligence and cognitive abilities, leads to a significant decline in general knowledge, and can lead to memory problems.
Mood problems can also arise. You may become more anxious or aggressive when you are not intoxicated.
Additionally, marijuana has been associated with eye problems, including:
- Conjunctival hyperemia (discharge from the eye).
- Less tear production.
- Light sensitivity.
- Ptosis, or drooping eyelid.
- Blepharospasm, or uncontrolled twitching eyelid.
- Nystagmus, or shaking eyes.
Medical Studies Show That Alternate Forms of Marijuana Can Cause Harm to the Eyes
Today, there are new methods of ingesting medical cannabis that could be less addictive. For example, lozenges, topical oils, and creams have all been developed to reduce the risk of getting high while benefitting from potential medical effects.
Unfortunately, these newer methods of medical marijuana use do not work to lower intraocular pressure. A study found that eye drops containing THC did not lower intraocular pressure at all. Another study found that smoking marijuana lowered intraocular pressure, and the amount of cannabis ingested would lower IOP in measurable ways, but ingesting more cannabis would not lead to effects that lasted longer. The body still metabolized THC’s peak effects in three to four hours.
Because the effects on IOP last only a few hours, medical marijuana does not help to maintain stable low eye pressure, which is necessary to reduce damage to the optic nerve.
Some studies suggest that marijuana can increase optic nerve damage. Cannabis use decreases blood flow throughout the body. If the optic nerve does not receive enough oxygen through the bloodstream, it will begin to die, which will lead to further vision loss.
A study on CBD oil in laboratory rats found that there was a paradoxical harmful effect. Since THC seems to be the chemical that lowers IOP, using medical marijuana with less THC can be worse for your eyes. The study reported an 18 percent increase in intraocular pressure in the rats who used CBD oil, which lasted for about four hours.
Eye Doctors Understand the Best Course of Glaucoma Treatment
Ultimately, the best treatment for glaucoma keeps eye pressure in a healthy range all day. Eye drops and some forms of surgery can help to maintain lower eye pressure for months or years. Eye drops must be applied consistently, but they will be used less often than medical marijuana would need to be used, and they have fewer impactful side effects.
Glaucoma. (July 2019). National Eye Institute (NEI).
What Is Marijuana? (September 2019). National Institute on Drug Abuse (NIDA).
CBD Oil May Worsen Glaucoma. (February 2019). American Academy of Ophthalmology (AAO).
- Surgery & Cost Info
- Glaucoma Laser Surgery
- Medications to Avoid with Glaucoma
- What Is iStent for Glaucoma?
- Types, Timelines & Treatments
- Timelines & Prevention
- Open-Angle Glaucoma
- Narrow Angle
- Glaucoma Medications
- Modern Treatment Options
- Pigmentary Glaucoma
- Can it Be Prevented?
- Acute vs. Chronic
- How to Spot the Early Signs
- Exfoliation Glaucoma
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People who have glaucoma often wonder if there are better forms of treatment than eye drops or surgery. This led to an interest in marijuana, including the use of CBD. Learn what studies say about the effect of marijuana use on glaucoma.