The use of cannabis for medicinal purposes is a rising topic in the United States. Cannabis has been used around the world for both recreational and medicinal reasons for many centuries.
Cannabis has many names but is commonly referred to as marijuana. Cannabis contains several components, called cannabinoids, each with unique properties. One such cannabinoid is known as cannabidiol, or CBD. CBD has both pain relieving and anti-inflammatory actions that support its use for medical purposes. CBD may cause side effects though, and some reports show evidence of more severe side effects experienced by elderly people and by women. 1
Currently, research to discover therapeutic uses of CBD for various diseases is ongoing. Some specific disease states being studied include multiple sclerosis, cancer, and glaucoma.1 In this article, we will discuss the role of CBD as treatment for people with glaucoma.
What is glaucoma?
Glaucoma is an eye condition that occurs when there is damage to the optic nerve. Glaucoma develops from high pressure build up in the eye. Eventually, this damage can lead to loss of vision or blindness. CBD for Glaucomais a gradual condition which means that it takes time for noticeable effects to develop. Therefore, it is important to get a yearly eye check up with your optometrist.2
Types of glaucoma
Symptoms of glaucoma depend on the type of glaucoma that you have. The types of glaucoma are listed below:
- Open-angle glaucoma: This is the most common form of glaucoma. The drainage area of the eye is partially blocked causing fluid buildup in the eye.
- Acute angle-closure glaucoma: In this type of glaucoma, fluid cannot circulate through the eye due to a narrow drainage angle.
- Normal-tension glaucoma: The cause of this form of glaucoma is unknown. In normal-tension glaucoma, the optic nerve is damaged, even with normal eye pressure.
- Glaucoma in children: The optic nerve is damaged from either drainage blockings or another medical condition.
- Pigmentary glaucoma: In this type of glaucoma, pigment granules build up which block fluid from draining from the eye. Pigment granules contribute to the color of the eye.2
How do you get glaucoma?
As mentioned before, glaucoma results from optic nerve damage. The optic nerve transmits images you see to your brain. When the nerve is damaged, the signals that communicate between the eyes and the brain are compromised. This causes blind spots to develop in your vision. In addition, fluid buildup increases eye pressure. This happens when fluid is overproduced or not adequately drained, causing eye pressure to increase.2
Genetics is another way in which one can get glaucoma. Glaucoma is a genetic trait and can be passed down generations within a family.2
There is no cure for glaucoma, but options for symptom relief exist. Some options include medications and/or surgery to relieve symptoms associated with glaucoma.
Can I use CBD for glaucoma?
There are no current treatments for glaucoma. The results are irreversible once the optic nerve is damaged.2 However, cannabis has been suggested to reduce symptoms that arise from glaucoma.3
In 1971, it was discovered that cannabis can reduce pressure in the eye.3 The reduced optic pressure was found to be due to the THC component of cannabis rather than the CBD componenet.1 THC, tetrahydrocannabinol, is a cannabinoid in the marijuana plant that produces psychoactive properties.1
Currently, the National Academies of Sciences says that there is limited evidence that cannabis is ineffective for decreasing eye pressure in glaucoma patients.4
What are some problems from using cannabis?
The cannabis plant contains both THC and CBD, among many other components.1 THC has psychoactive side effects; therefore, THC produces more noticeable side effects than CBD.5
Many forms of cannabis exist. A major consideration to take into account when consuming cannabis is the route of administration chosen. Smoking and inhaling cannabis causes decreased short-term memory, cognitive impairment, sleepiness, and euphoria. It also increases heart rate and heart palpitations, or irregular heartbeats. Smoking or inhaling any product long-term can lead to lung disease and cancer because smoke is toxic to the lungs.5
The route of administration with the most evidence for reducing eye pressure is smoking and inhaling. The topical route does not penetrate the eye effectively to reduce the pressure caused by glaucoma. In addition, the topical route has caused irritation and some eye injury.5
Another concern with using cannabis as a therapeutic agent is its abuse potential and tolerance. Cannabis, specifically the THC component, is associated with addiction. Using cannabis regularly can also lead to tolerance, a situation in which higher doses are needed to feel the same effects.5
Why is there limited evidence for cannabis as ineffective for glaucoma?
Very few studies have been conducted researching cannabis therapy for people with glaucoma. One of the current issues with recommending cannabis for symptom relief is the adverse effects associated with cannabis use. Pressure in the eye was reduced with the use of THC, not the use of CBD. So, using THC as a therapeutic agent would lead to more psychoactive side effects and in this case, the benefit of using THC does not outweigh the risks of the side effects.1
In addition, cannabis has a short duration of action. This means that the therapeutic effects would only last a short amount of time, which would cause patients to increase the number of times they use cannabis to feel symptom relief. This creates a problem because the more cannabis is used, the more tolerance is developed. As a result, there would be an increase in use and dose.5
Furthermore, there is no scientific evidence that cannabis is beneficial for people with glaucoma.5 Glaucoma is a gradual, progressive disease that worsens with time.2 Studies have not been done to observe the effects of cannabis with the progression of the disease.5
In one review, cannabis was shown to negatively impact cardiovascular and neurological effects, which may decrease the benefits of lowering eye pressures. In other words, the risks outweighed the benefits when considering cannabis for glaucoma.6
Eyes have an important function and must be taken care of to avoid loss of sight and complications associated with vision loss. Methods for slowing down the progression of glaucoma exist if it is caught early, such as:
- Regular yearly check-ups with an optometrist
- Knowing your family history of eye health
- Regular exercise
- Be adherent to your prescription eye drops, even if you are not symptomatic
- Protect your eyes with sunglasses when you go outside or use eye protection when participating in extreme sports2
Cannabis use for medicinal and therapeutic purposes in many diseases is a trending topic. Cannabis contains both THC and CBD. THC and CBD have different effects on the body and brain.1 THC is the main contributor for reducing eye pressure in people with glaucoma, but causes psychoactive side effects.1,5 CBD does not have psychoactive properties.1 The lack of evidence and the side effects associated with cannabis use in people with glaucoma are the main reasons why the medical community has not accepted cannabis as a therapeutic option.4,5 Glaucoma is a gradual and progressive disease that is irreversible, but preventative strategies may help slow it down.2
- Williamson, E M, and F J Evans. “Cannabinoids in clinical practice.” Drugs vol. 60,6 (2000): 1303-14. doi:10.2165/00003495-200060060-00005
- Mayo Clinic. “Glaucoma.” Mayo Clinic, November 2018, https://www.mayoclinic.org/diseases-conditions/glaucoma/symptoms-causes/syc-20372839
- Mouhammad, Zaynab Ahmad, and Miriam Kolko. Ugeskrift for laeger 180,29 (2018): V11170861.
- National Academies of Sciences, Engineering, and Medicine. 2017. The health effects of cannabis and cannabinoids: The current state of evidence and recommendations for research. Washington, DC: The National Academies Press. doi: 10.17226/24625.
- Rafuse, Paul, and Yvonne M Buys. “Medical use of cannabis for glaucoma.” Canadian journal of ophthalmology. Journal canadien d’ophtalmologie 54,1 (2019): 7-8. doi:10.1016/j.jcjo.2018.11.001
- Novack, Gary D. “Cannabinoids for treatment of glaucoma.” Current opinion in ophthalmology 27,2 (2016): 146-50. doi:10.1097/ICU.0000000000000242