Can Cannabis Help With Glaucoma?

A simple Google search is enough to see just how beneficial cannabis is for the human body. It's as if the plant evolved specifically to produce phytochemicals that closely resemble our endocannabinoids — in case things go wrong, the plant is always there for us.

Now, that's quite a stretch, huh? Anyway, the phytocannabinoids have evolved since their existence to protect the plant from various environmental factors like UV light and desiccation.

But one can't deny the endless health benefits of cannabis — it may help with depression, anxiety, insomnia, chronic pain, ALS, and so many more. So, when we are thinking along those lines, it does pose a question, can cannabis be used to treat glaucoma?

Well, you are not alone to ask this question! Scientists around the world have been asking the same question for many years and are actively working to find the answer. So far, cannabis does show some potential but there is also a major risk when it comes to cases of glaucoma.

So, can cannabis treat glaucoma or not? Read on to find out more about what glaucoma really is, how it develops, and how cannabinoids play a role in it. 

What is Glaucoma?

Glaucoma is the second leading cause of blindness across the globe, affecting people of all age groups, but primarily those over 60. It is estimated that over 70 million people suffer from this condition, but since the symptoms tend to be so elusive, only up to 15% of patients know about their condition.

Glaucoma is a group of diseases that leads to a degeneration of the eye's optic nerves, which is a crucial part of your central nervous system as it transmits electrical impulses from your eyes to the brain. And when that denigrates beyond a point, the patient experiences loss of vision. 

The symptoms of glaucoma are:

• Severe pain in the eye
• Vomiting and nausea
• Headaches
• Red or tender eyes
• Seeing rings around lights 
• Blurred vision
• Vision loss

This condition also has some other symptoms, but they vary from case to case. 

And experts speculate that some people are more at-rick to glaucoma than others, due to various risk factors, such as the following:

• Being older than 60
• Being Asian, African, or Hispanic 
• Hereditary of glaucoma 
• Other medical conditions like heart disease, high blood pressure, and diabetes
• Thin corneas
• Other eye injuries 

Glaucoma Terminology

Since things are going to get a little technical below, let's take a look at some of the common terms related to this condition.

Retina

The retina is like a camera sensor of your eye — this layer of tissue contains photoreceptors, shaped like cones and rods, which convert light rays into electrical impulses. It is located in the back of the eye, close to the optic nerve. 

Retinal Ganglion Cells

These cells transmit visual data from your retina to the specific regions of the brain, and they also make up the optic nerve.

Aqueous Humor

Aqueous humor is a clear fluid that contains a bit of glucose and protein along with higher amounts of ascorbic acid and lactic acid. This liquid is produced in the ciliary body, a muscular tissue, and from there it makes its way to the eye chambers, distributing these nutrients with oxygen.

Posterior Chamber

After the ciliary body, aqueous humor flows through the posterior chamber that sits between the iris and the pupil.

Anterior Chamber

After the pupil, aqueous humor makes its way to the anterior chamber, which is located between the cornea and the iris, and then it flows to the trabecular meshwork.

Trabecular Meshwork

This porous tissue is located on the front of the eye and it aids the drainage of aqueous humor, helping regulate pressure within the eye. 

Iris 

Iris is the colored part of the eye — black, brown, green, and so on — and this part is responsible for regulating the light flowing into your eye. It uses a pupil to modulate the amount of light.

Cornea

Cornea is the outermost lens, and it helps protect your eyes while also focusing the light onto the retina. 

What are the types of Glaucoma?

Now that you know the basics of what makes up an eye, we can understand how this condition affects the eye's function. 

In essence, glaucoma is mostly related to the intraocular pressure (IOP) within the eye, which results in a disrupted flow of aqueous humor, causing damage to the ocular nerve. This eventually leads to vision loss. 

However, scientists are still not sure what exactly causes glaucoma, but they have found that IOP does build up in the eye due to the narrowing of posterior or anterior chambers. 

Here are the three most common types of glaucoma and how they affect vision.

1. Primary Open-Angle Glaucoma

Primary open-angle glaucoma causes the iris to collapse into the posterior chamber, which disrupts aqueous humor flow through the pupil. This disruption further leads to a backflow, increasing the IOP levels. 

At the same time, part of the iris collapses forward, which blocks the flow of aqueous humor into the trabecular meshwork. And the tissues on the back of the eye experience tremendous mechanical stress, which causes deformation or decompression, disrupting the neurons from firing properly. 

In some cases, the blockage also disrupts the flow of other trophic factors into the retinal ganglion cells, which further leads to neurodegeneration. 

2. Primary Closed-Angle Glaucoma

On the other hand, there is primary closed-angle glaucoma, which is a result of increased resistance of the trabecular meshwork, causing aqueous humor to completely drain out from the anterior chamber. 

Since aqueous humor flows through the pupil but fails to outflow via the trabecular meshwork, IOP in that region increases, leading to other symptoms of glaucoma.

3. Normal-Tension Glaucoma

The third type of glaucoma that some patients may experience occurs when the optic nerve is disrupted or damaged even if the IOP levels are normal. Scientists don't know what causes this type of glaucoma, but some experts believe that this could be a result of an interrupted blood flow due to a clot around the optic nerve. But more research is ongoing to find the exact cause. 

What are the Conventional Treatments for Glaucoma?

Currently, no cure exists for glaucoma, however, patients can opt for various treatment options that can produce the IOP lowering effect, which may be effective in slowing down the progression of vision loss, such as the following.

1. Medications

Patients are often prescribed various medications that can reduce IOP in the eye, and these commonly come in the form of pills or eye drops, the latter being the most common one. These medications include beta-blockers, prostaglandins, alpha-adrenergic agnostic, or carbonic anhydrase inhibitors.

2. Surgery

Many patients may also be recommended to undergo surgery if IOP is increasing due to a blockage. The surgery aims to make a clear path for the fluid or terminate the tissue that may be leading to increased IOP.

However, surgeries are often a medical emergency and not recommended upfront. Most doctors recommend starting with medications, but if the case is severe, the patient may undergo a laser procedure — laser peripheral iridotomy — which uses a laser to punch holes in the iris, allowing more fluid movement. 

How Does Cannabis Help with Glaucoma?

Cannabis has helped patients deal with various conditions, but can it help with glaucoma? While research is still going on to explore the potential of cannabis in reducing IOP levels, experts speculate that it can be helpful.

But for this, you must first understand the endocannabinoid system in the eyes and how cannabis interacts with it. 

The Endocannabinoid System 

The endocannabinoid system was first discovered in 1988, but even today, experts are still uncovering various aspects of it. But from what we know so far, the endocannabinoid system (ECS) is the universal regulator of the body — it exists in the brain, immune system, skin, bones, metabolic processes, muscles, and connective tissues. 

Essentially, this system's job is to maintain homeostasis in your body, i.e., a fine balance of various biological functions so that your body stays healthy and runs smoothly. 

And since it is regular, the ECS exists between neurons as receptors. And it comprises two types of receptors — CB1 and CB2 receptors. And the two primary molecules that are used for signaling by ECS are anandamide (the bliss molecule) and 2-AG, which are also endocannabinoids. Additionally, the ECS is helped by enzymes that build or break down the endocannabinoids.

Phytocannabinoids in Cannabis

On the other hand, cannabis also contains over 100 phytocannabinoids, including THC, CBD, CBG, CBC, and many others. The fascinating thing is, many of these phytocannabinoids from cannabis fit perfectly into the human cannabinoid system since their molecular structures resemble that of endocannabinoids. 

Because of this, when you consume cannabis, the phytocannabinoids can perfectly fit into the ECS receptors and produce various effects. For example, when you consume cannabis, THC ends up in the CB receptors, making them produce more of a certain chemical, which leads to a high. 

SO, what's the conclusion? These phytocannabinoids are power compounds for the human body because they can influence our universal regulators (ECS) and all the processes or organs that ECS looks over. And this includes the eyes. 

The ECS of the Eye

The endocannabinoid system is also present in most ocular tissues of the eye, making it possible for cannabis to influence the homeostatic apparatus of the eyes. For instance, 2-AG and anandamide are present in the eyes, except the lens, and they are accompanied by CB1 receptors in the ciliary body and retina. 

According to some preliminary research, CB2 receptors are also present in the retina and front of the eye along with other eCBome receptors and enzymes. 

Since the ECS is responsible for maintaining balance, its malfunction can drastically affect the eyes. For example, according to the theory of clinical endocannabinoid deficiency, migraine, IBS, and fibromyalgia — which occur without a clear cause — could be due to a malfunctioning ECS or endocannabinoid deficiency. 

Experts suggest that each individual has a unique endocannabinoid tone, i.e., specific circulating levels of endocannabinoids or the sweet spot. 

Although the research is limited, it's uncovered that malfunctioning ECS signaling could be causing glaucoma and various other eye conditions. For example, in age-related macular degeneration, the anandamide levels in the ciliary, retina, and cornea are higher than normal, and in diabetic retinopathy, 2-AG, and anandamide levels were elevated.

But one study showed that the endocannabinoid levels in the ciliary body were lower than usual. More research is required, but so far, experts speculate that THC and CBD can act as alternatives to the signaling molecules 2-AG and PEA. This is because THC resembles anandamide and CBD mimics PEA. More on this is below.

Of course, more studies are required to understand ECS' role in glaucoma and if phytocannabinoids can be used to replace the missing endocannabinoids or regulate the endocannabinoid within the eye. 

Potential Role of Cannabinoids in Treating Glaucoma

We delved a little into phytocannabinoids' role in regulating ECS, but let's dive deeper and see what the research suggests. 

1. THC

THC or tetrahydrocannabinol is the primary psychoactive cannabinoid present in the cannabis plant, and it works by activating CB1 receptors in CNS. According to a review published in Neural Plasticity, a journal, THC can modulate IOP.

The study cited a collection of animal subjects, like rabbits, rodents, and primates, to determine if THC can be used to target ECS to treat glaucoma. And human studies are ongoing to test THC's efficacy in treating glaucoma. 

However, experts believe that THC can help more than just shifting IOP within the eye. Hence, studies are trying to determine if cannabinoids are neuroprotective and protect the optic nerve from damage. 

2. CBD

On the other hand, CBD is the second primary cannabinoid present in cannabis, and this cannabinoid is not psychoactive but it does produce a lot of therapeutic benefits for the user. This is because CBD has a low affinity for CB1 and CB2 receptors, but it does influence ECS enzymes and binds to TRPV-1.

So far, research suggests that glaucoma could be caused due to lower levels of anandamide in the eyes. And CBD can be used to elevate anandamide levels as it temporarily inhibits the enzymes that are responsible for breaking the endocannabinoid down.

However, some studies also show that the outcomes aren't so promising. In fact, some studies have shown that CBD may raise IOP within the eye, increasing the risk for the patients. But this evidence is inconclusive and more studies are required to reach a conclusion. 

Benefits of Cannabis for Glaucoma

Nonetheless, cannabis does seem to have some benefits for glaucoma patients, according to research. For example, various animal studies state that cannabinoids may increase the flow of blood in the eye, which is crucial for its structure. And many cannabis experts claim that cannabis can even cure glaucoma. 

However, here are some of the benefits of cannabis for glaucoma cases:

• Cannabis medications do not produce many severe side effects often associated with pharmaceutical medications 
• Cannabis may reduce the need for surgery for many glaucoma patients
• THC can help manage the pain associated with glaucoma 

But it is crucial to take into account that the research so far is inconclusive and highly debated. Many experts believe that cannabis can be a cure but others argue that it can make things worse. This is because there are some potential risks, too.

How can a Glaucoma Patient use Cannabis for Relief?

Despite the debate, many patients have found relief from the symptoms of glaucoma thanks to cannabis. So, glaucoma patients can try cannabis for themselves and see if it helps them. And here are some ways they can do so.

1. Smoking or Vaping

The most common way of consuming cannabis is smoking it, whether you roll the herb in a joint or a blunt and blaze it. This is a quick, effective way to consume cannabis, but there are obviously some health risks associated with it.

In that case, a user can even vape cannabis, which uses a cartridge to heat cannabis oil. Vaping is safer than smoking and produces the same effects as joints. 

2. Orals or Edibles

The second most common way of consuming cannabis is by eating it. All you need to do is mix some cannabis concentrates into food or beverages and consume them. But this process takes a couple of hours to produce the effects and can be strong since dosing is a little tricky.

3. Sublingual

One of the fastest ways of consuming cannabis is sublingual, where you place a drop of cannabis extract under your tongue. It diffuses and gets right into your bloodstream, and the effects produced are strong, too.

If you are planning to try cannabis for glaucoma relief, it is advised that you first consult your doctor. As mentioned earlier, while cannabis can help with the symptoms of glaucoma, some experts are still varied with the herb as it may worsen glaucoma. 

A medical professional would be able to guide you better in making the decision and also help you figure out the right dosage that benefits you and not the other way around. So, always consult your doctor.

What are Some Other Alternatives that can Help with Glaucoma?

So far, no treatment can cure glaucoma or reverse its effects, but medication can help prevent further damage to the eye. And in severe cases, surgery can come in handy too. However, a glaucoma patient can also try various other alternatives to help with the symptoms of glaucoma.

Here are some of the alternatives that you can use to deal with glaucoma symptoms:

• Omega-3 fatty acids — these fatty acids can help prevent oxidative damage and inflammation in the region, and some experts even speculate that it could help prevent glaucoma entirely, but more research is required 
• Melatonin — if the patient is unable to sleep well, melatonin can help as it can act as a gentle sedative
• Antioxidative supplements — glaucoma is accompanied by oxidative damage, and here, antioxidants like vitamin A and vitamin C can help prevent further damage
• Vitamin B supplements — one study stated that thinner retinal nerves were linked to low vitamin B12 levels in the body, so vitamin B supplements can help 
• Ginkgo biloba — a herb that has various anti-inflammatory effects on the human body, so it can help with the pain associated with glaucoma
• Dark leafy green vegetables — according to some studies, these vegetables can reduce the risk of developing glaucoma in the first place 
• Lifestyle changes — following a balanced diet, maintaining a moderate weight, and working out regularly can help one manage glaucoma more efficiently 

As with any other alternative, it is advisable to consult with your doctor before trying anything new. Some of these alternatives may interfere with the glaucoma medications, rendering the latter less effective, or in worse cases, making the symptoms worse. 

Summary: Can Cannabis Help With Glaucoma?

Glaucoma is a nasty condition, being the second biggest contributor to complete vision loss across the world. But there is light at the end of the tunnel in the form of cannabis. 

So far, studies show that cannabinoids present in cannabis can be quite effective at managing the symptoms of glaucoma, and a few studies speculate that cannabis can even cure glaucoma. 

Until more is known about cannabis' effect on glaucoma, one must tread carefully in using cannabis to help with glaucoma. Many studies also claim that cannabis makes the symptoms worse and the progression of the condition faster.

However, cannabis can help you manage the symptoms like pain or inflammation associated with glaucoma. But it is recommended that you consult your doctor first to know if cannabis can be a viable option for you.

Cannabis is transforming medical science in ways we could not have imagined before legalization, but there is still a long way to go. A lot more studies must be conducted and prove multiple times that cannabis can in fact help with glaucoma. Only then can one use cannabis confidently.

Until then, it is best to stay cautious and discuss with an eye doctor before using cannabis.