CBD For Ocular Pain
As much as I love blogging about CBD. There is just one thing I hate. After staring at a glaring screen for hours on end my mind wants to keep working but my eyes are screaming in agony.
Yup, that pesky ocular pain.
It is such a nuisance, all day long I would have a throbbing pain right above my eye, with a persistent little headache to match.
Just recently I had some terrible eye pain in my left eye for a couple of months, and couldn’t afford to take much of a break from the computer. I decided to do some eye exercises, use eye drops and take little intermittent breaks. Of course, nothing worked, I was one step short of scheduling an appointment with an eye doctor.
Then like a light bulb gone off in my head, I said to myself “I blog about CBD, it has a whole host of cures, maybe there is a CBD eyedrop”. I consulted my friend Google, and sure enough, someone sells CBD eye drops.
Let’s take a look into my experience right after I briefly describe what CBD is for those who don’t already know.
What is CBD
In case you don’t already know, I’ll go over briefly what exactly CBD is. CBD, which is short for cannabidiol, is the non-psychoactive component of the cannabis plant.
CBD is known for its whole array of effects and for its ability to stimulate the receptors in the endocannabinoid system.
CBD is becoming popular because it brings you all the health benefits of the cannabis plant with a low side effect profile and without producing a high that is associated with THC.
Some research has shown the effectiveness of CBD in treating myriad diseases and conditions, including for eye pain.
Eye Pain: Some Background Info
In general, perception of pain is considered a vital self-defense mechanism that our body utilizes to protect us from harm.
Pain basically tells us to stay away from harmful things around us, for example if you were to place your hand over a flame, you would experience pain and hence pull it away, avoid getting burned.
Ocular pain, a source of acute discomfort, may be a signal that prevents damage to the eye (from exposure to a noxious chemical or a mechanical probe, for example).
But sometimes, under certain circumstances, pain signals can become dysfunctional. Impulses of pain for prolonged periods of time will lead to the nervous system being locked into an over sensitive mode in which even small pain stimuli lead to big responses.
This is called neuropathic pain, and it is a condition that affects a significant portion of the population.
Corneal Neuropathic Pain (CNP) Explained
The cornea of the eye is the transparent lid that covers and protects the eye from injury. It is a very sensitive area, having one of the highest concentrations of sensory nerves in the body. This fact makes the cornea highly sensitive to many things such as touch, temperature and numerous compounds.
Contact with the cornea also triggers an involuntary nerve reflex that causes us to close the eye.
When injury to the cornea occurs, it’s often associated with hyperalgesia (high sensitivity to pain) and corneal neuropathic pain (CNP).
Typically, opioids and non-steroidal anti-inflammatories (NSAIDs) are the choice of prescription for this type of neural pain.
However, due to the bad efficacy and the damage that these types of drugs can cause in the long term, physicians are working on new types of drugs with safer side effects such as cannabinoids.
This is because our body’s own cannabinoids are known to activate receptors called CB1 and CB2, which are known to produce pain-relieving effects. The can also increase endorphins, which are also associated with a reduced pain response.
Barriers to CBD Effectiveness in Treating Eye Pain
Using natural and synthetic cannabis extracts is difficult for topical applications because of their lipophilic profile, which makes it hard to dissolve the cannabis oil formulations in water because the two are immiscible.
The problem is even more pronounced when it comes to cannabinoid-infused eye drops, because they have to penetrate the water-like layer over the cornea in order to perform their function at the eye.
One workaround to this problem is smoking cannabis which has been used since the 1980s and is known by its users for reducing intraocular pressure and relieving some symptoms of glaucoma.
Another more practical workaround was the use of light mineral oils as a transport vehicle for the CBD. Cannabis mixtures were dissolved in light mineral oil and applied topically to the eyes of participants with high ocular pressure.
This lead to a reduction in ocular pressure, but the problem that remained was that the mineral oil mix was somewhat irritating for some users.
Nowadays, new formulations rely on a water based mixture, or emulsifiers to help reduce irritation from the mixtures.
Studies Supporting CBD’s Benefits for Eye Pain
In a major study conducted at the Department of Pharmacology at Dalhousie University in Nova Scotia, Canada, researchers showed that CBD can act through unique receptors to reduce pain and inflammation in the cornea (which is the outer transparent layer of the eye).
Typically, injury in the cornea leads to a dysfunction of corneal nociceptive (pain) signaling. In addition, it may also lead to an overly sensitive cornea.
CBD which acts on the endocannabinoid system has been reported to have analgesic (pain relieving) and anti-inflammatory effects on the cornea,
In the study, pharmacists investigated the antinociceptive (anti-pain) and anti-inflammatory effects of cannabinoids (such as CBD).
CBD is reported to have an effect at cannabinoid 1 (CB1R) and cannabinoid 2 (CB2R) receptors. In addition, it’s also known to have an effect on noncannabinoid receptors in an experimental model of corneal sensitivity to pain (hyperalgesia)
In the study, the researchers induced a pain response in the eyes (corneas) of mice by cauterizing them (applying heat).
The cauterized eyes were then treated with a topical solution containing phytocannabinoids such as CBD or THC.
The researchers then applied topical capsaicin (which is the same chemical found in hot foods) to the mice’s eyes and measured the behavioral pain responses using video recordings. They then quantified these responses to capsaicin to determine the effect with and without CBD.
Finally, the mice were euthanized after the postcorneal injury. Their tissue was then subjected to immunohistochemical analysis to determine the level of infiltration of neutrophils (immune cells).
By measuring the quantity of neutrophils in the eyes, the researchers could determine how much of an immune reaction occurred in the eyes of the mice (which is also correlated with the level of inflammation in the eyes).
Cauterization of the corneas lead to a stronger pain response in the mice as was determined from the video recordings.
In addition, cauterization also lead to a higher count of neutrophils (immune cells) in the corneal tissue, which is indicative of inflammation.
The interesting part is that application of CBD to the eyes lead to both:
- A reduction in the pain response experienced.
- A reduction in the immune response (less neutrophils and hence less inflammation).
Moreover, the anti pain and anti inflammatory actions of THC and CBD were both blocked when an antagonist to the CB1R (cannabinoid 1) receptor was used.
An antagonist in this case is a compound the blocks the action of the CBD by preventing the CBD from binding to the receptor.
So in summary, the study concluded that topical cannabinoids reduce corneal (outer eye) pain and inflammation.
The antinociceptive and anti-inflammatory effects of CBD specifically was mediated by the cannabinoid receptors such as CB2R, in addition to other receptors too.
The researchers believe that cannabinoids such as CBD, CBV, or THC could prove to be a novel clinically effective treatment for corneal pain and inflammation that stems from from ocular surface injury (injury to the corneal membrane).
They think that drugs developed from CBD could even be potentially approved by the FDA for prescription use by doctors.
How Effective is CBD for CNP?
It is now known that activation of the endocannabinoid system receptors reduces pain sensation within the central regions of the brain and peripheral pain-sensing regions. CB1 and CB2 receptors are known to both be involved in lowering pain.
Corneal cells in the eye are also known to have CB1 and CB2 receptors, which leads scientists to believe that CBD should be quite effective in reducing pain, as has been proven in laboratory studies (on animals).
The research that has been performed has confirmed that all the animals that were administered CBD topically, showed a decrease in their ache. This was calculated by using the rate of eye blinking as a measure of pain sensation.
Moreover, in this study, the researchers deemed the likelihood of this reduction in pain to be a random end result to be less than 0.0001, so they are almost certain that CBD did cause reduction in eye pain.
Testing out CBD For My Ocular Pain
So now that we know what CBD is, I can explain what happened when I used it to try to treat eye pain.
First off, I was skeptical but assumed it might work at the same time since CBD has anti-inflammatory properties. I figured the CBD would reduce the pain in my eye as well.
The CBD eye drops had arrived. They came in a typical eyedropper looking bottle with a narrow tip in order to disperse a couple of drops.
The directions were as follows:
Shake well and place 1-3 drops in each eye daily as needed.
So I did just that.
The first day, I didn’t really know much, my eye felt a little more lubricated and less irritated but it didn’t seem to bring the pain down.
I figured, what the heck, I’ll use it a few more days. Literally the second day, my pain had subsided. Wow! That was great.
Now the third day; The pain had completely gone away. I couldn’t believe it, prior to this I had tried some regular over the counter eye drops and nothing would relieve this pain, I was just living with it for a while. These eye drops seriously worked well.
This seemed like an amazing unconventional use for CBD and haven’t really heard of it being tried for ocular pain before.
I continued to use it for the rest of the week. This is where the eyedrops became more of a nuisance. When using the eye drops for a prolonged time, it felt like my eyes were starting to dry out. It was hard for them to keep lubricated. However, as soon as I stopped using the eyedrops my eyes retained their natural saturation.
It didn’t matter anyway because after the pain had gone, it didn’t return, I didn’t need to use the CBD eye drops any longer than I had to.
If you are going to use CBD eye drops for pain, I recommend only using it until the pain subsides, that was the experience I had.
There you have it. I put CBD eye drops to the test and found a new discovery. It seemed, for me at least, that CBD eye drops were an excellent remedy for my ocular pain. My pain was intense at times and persistent, nothing I did would relieve the pain.
Finally through the use of the CBD eye drops that pain had vanished.
We also learned that when I took the eye drops for a prolonged time, my eyes began to feel dry and itchy. The best advice is to just use the drops until the pain subsides. Hope this article was helpful.