Marijuana and Glaucoma
While the topic of Marijuana and glaucoma are considered debatable, new light is shining on Marijuana’s neuroprotective properties.
Photo credit: Human Health
Glaucoma is a disease resulting from progressive optic nerve damage. It’s most severe symptoms are a loss of vision and potential blindness. According to the Glaucoma Research Foundation, glaucoma is the second leading cause of blindness affecting around 60 million people worldwide.
Cause, Diagnosis and Treatment
Visual information is carried to the brain by the optic nerve. The optic nerve itself is made up of axons of retinal ganglion cells. Damage to these cells causes their irreversible death which in turn leads to vision impairment. Intraocular pressure (IOP) is believed to be the main cause of glaucoma. The mechanism by which IOP is regulated involves the drainage system of our eyes.
The aqueous humour, which nourishes both lens and cornea, is secreted by the ciliary body. This fluid is then recycled through the trabecular meshwork which acts as a filter that regulates aqueous humour outflow resistance necessary to maintain a normal intraocular pressure.
Aging, accompanied by increased oxidation and normal cell loss, extracellular debris, and mitochondrial damage have all been associated with stiffening of the trabecular meshwork. In turn, the draining capacity is lowered and the IOP increases due to fluid build up.
Aqueous humour outflow is shown in turquoise
Unfortunately, diagnosis of glaucoma often means that damage has already taken its course. The initial symptoms are the loss of peripheral vision, and if left untreated can progress into blindness. To this day, Glaucoma has no definite treatment. The process can only be slowed down or in rare cases halted. Currently, three approaches are present:
- Medical treatment
None of these methods have been found to work better than the other. Surgery has largely been replaced by medical treatment following the discovery of prostaglandins.
Sadly, medicinal treatment has its limits and is accompanied by resistance. More than 75 % of patients require alternative drug combinations only after two years of treatment. The side effects of these drugs often lead to diminished quality of life due to a harsh side effect. On the other hand, some of these treatments are simply poor in effect and leave patients desiring for alternative medicine.
Let There Be Marijuana
In the past decades, the medical potential of marijuana has changed its course. It is suggested that the use of marijuana derivatives could have great potential in treating illnesses such as epilepsy, multiple sclerosis, cancer and many more.
It is no surprise since records of it therapeutic effects have been kept by Pharmacologist Shen Nung in 2737 BC. In the 1800’s , following animal studies, it was concluded that marijuana showed effectiveness in treating rabies, rheumatism, epilepsy and tetanus under safe conditions.
The subject of Marijuana and glaucoma has also been around for longer than imagined. In 1971, Hepler and Frank observed that marijuana smoking subjects showed reduced IOP. This discovery led to subsequent investigation in the following years, mainly by a scientist named Keith Green.
The smoking of controlled doses of marijuana has shown to decrease intraocular pressure by a mean of 25 % in human subjects. This reduction was comparable to recently approved glaucoma medication.
A study published in 2005 on Marijuana and glaucoma involved a 60-year-old patient who had gone through surgery. The subject in question was intolerant to several glaucoma medication, some of which were simply ineffective. On the recommendation of her ophthalmologist, she began using marijuana in the form of cigarettes and edibles. The results were significant in that her IOP was successfully controlled with no further loss of her visual field in the past two decades. If this isn’t significant enough for further research on marijuana and glaucoma, then I don’t know what is.
Mechanism of action
The exact mechanism by which Marijuana reduces IOP is unknown. However, the discovery of the CB1 and CB2 receptors located directly in the tissue of the eyes is promising. What is even more interesting is that these receptors are highest in density in the trabecular meshwork, which we talked about earlier. These findings are significant in that they suggest a direct involvement of cannabinoid receptors in aqueous humour production.
While the topic of Marijuana and glaucoma are considered debatable, new light is shined on Marijuana’s neuroprotective properties.
It is well documented that the cannabinoid receptors CB1 are mainly localised in the central nervous system. This localisation seems to support the ability of cannabinoids to protect neurons from a panoply of neurological conditions.
Studies have shown that marijuana derivatives have the ability to protect against brain injury during head trauma, toxins, and hypoxia.
The mechanism by which cannabinoids mediate neuroprotection seem to arise through a variety of signalling pathways which regulate the release of certain neurotoxic compounds and reactive oxygen species.
On the topic of marijuana and glaucoma, the scavenging of reactive oxygen species may actually protect the optic nerve from neuronal death.
Some argue that that the blood pressure reducing effects of cannabis may limit blood flow to the optic nerve, leading to more damage. However, marijuana has vasorelaxant properties which might actually be able to do just the opposite: increasing the ocular blood flow.
“I was diagnosed with Glaucoma in 1975. Within a year, I already knew that there was nothing absolutely nothing that was on the market then, worked for my glaucoma except for marijuana” – Elvy Musikka
While the connection of Marijuana and glaucoma may seem debatable, it is important to consider the potential alternative it provides for patients that have tried it all.
Elvy Musikka, a glaucoma patient in the federal Compassionate IND program for medical marijuana, has found no successful cure on the market.
She talks about her marijuana experience which was “the only medicine she ever needed” as the side effects of conventional drugs left her with horrid side effects.
She also speaks up about the ignorance revolving around the product and her personal experience with the medical system that left her helpless. You can watch her insightful Youtube interview below, posted by CannabisPatientNet.
Not only did Elvy control her glaucoma, she also discovered that marijuana took her away from the darkness of the condition and enlightened her life.
GW Pharmaceuticals, medical marijuana dispensaries, as well as physicians, have also supported the link between marijuana and glaucoma. Thomas Orvald, a cardiac surgeon that has collaborated with the Hemp & Cannabis Foundation, is one of them.
“The treatment for glaucoma is to somehow get the [intraocular] pressure down within the globe [of the eye]. It just so happens that one of the many virtues of cannabis is that it has the capability of decreasing intraocular pressure… Cannabis is a very effective way, used properly, to decrease the pressure within the eye and to preserve this wonderful retina back here that transcribes all the visual sights into the brain.” – Thomas Orvald, MD
The main concern around marijuana and glaucoma is the psychoactive effects that it induces. Another concern is that the reduction effects only last 3 to 4 hours when smoked. This short action time combined with the high limits the potential for continued use. Moreover, the smoking of marijuana cigarettes could be associated with lung damage but the research is unclear.
The discovery of cannabinoid receptors CB1 and CB2 allowed for he introduction of novel delivery pathways in the quest around Marijuana and glaucoma. Oral, sublingual and eye drops are novel ways of introducing THC. Eye drop formulations are the most desired alternative out of these three due to the lack of psychotropic side effects accompanied by the consumption of THC.
A formulation that delivers the active ingredient in sufficient concentration has not yet been found. This misfortune is mainly due to the low aqueous solubility of THC. Topical products have also been found to be irritating. However, the discovery of the CB1 receptors directly in the tissues of the eye might suggest that this route of application may still be the best option for localised treatment.
Marijuana and Glaucoma: The Future
Despite the concerns around the subject of marijuana and glaucoma, it is important to embrace the significance of recent advancements. The discovery of the neuroprotective nature of Cannabis is definitely an important milestone. The IOP decreasing effect of marijuana is the only alternative for some glaucoma patients. The discovery of CB1 localization in the optic nerve as well as the tissues of the eye opens an extremely important portal for drug delivery and mechanism of action.
More than 480 chemicals constitute the marijuana plant, from which research has only addressed a few : THC , cannabinol and cannabidiol. There is immense room for continued research and future discovery. If anything, our current knowledge of marijuana and glaucoma should only support further funding and investigation.
Moreover, recent advancement in microemulsion technologies have shown a potential increase in corneal absorption of cannabinoids. If further investigated, this could lead to the development of a solution that would solve all concerns at once.
Topical application is preferred since it allows direct action at the affected site where the cannabinoid receptors are located. Since this form of administration minimises the psychoactive and physical side effects associated with smoking marijuana, using it regularly would no longer cause a problem.
Another variable in the equation is public opinion. We must accept and learn from the personal experiences of patients. Some have only found relief to their condition through the use of marijuana.
Our pre-conditioned opinions are of no value and we have proved that countless times over the past decades. There is a heavy ignorance around this medicinal plant that we must overcome.
On the positive side of things, the public is becoming more open to the idea of Cannabis which shows a great leap ahead.
Read A Brief History of Cannabis in the USA.
Why is it that the medicinal properties of cannabis have been documented in ancient times? Why is it that conventional medicine didn’t do it for these patients? Why is it that patients develop tolerance to these medications? Why is it that marijuana has been more successful and consistent to some than what the market has to offer?
These are all questions we need to ask in order to successfully weigh the pros and the cons. We must not use the limitations as a reason to dismiss the potential of marijuana. Instead, we must use these new discoveries as the pieces of a bigger puzzle and continue the search.
We have to be driven by wonder rather than closed by belief
The current obstacles surrounding marijuana and glaucoma are of definite consideration. However, the speed at which new research has emerged in the past decades should only support future possibilities.
The medical potential of marijuana is a current topic due to its beneficial properties in several areas of medicine. With continued efforts, much like the one experienced in the past decade, the medicine of marijuana is bound to become more understood and accepted.
Scientific research will always be faced with complications, failures, and debate. I believe that the science behind marijuana and glaucoma is closer to success story than one of failure.
What is your position on marijuana and glaucoma? Do you think glaucoma patients should be more informed about the potential of marijuana and given the freedom of choice? Let us know your thoughts on social media.