I was still in a state of advised caution last Saturday when I received the first bottle of hemp (CBD) oil from a friend, who wanted me to try it for my vision. What has held me back until now has been my fear that â€śpap water is papâ€ť, as we say in Nigeria, that is â€¦ CBD oil or cannabinol or medicinal hemp cannot be from different from psychotic Indian hemp that I have known for about seven decades make its users high or stoned. But now, science and medicine are telling us that cannabinol comes from a non-psychotic specie of the cannabis plant known as hemp. Nevertheless, I remain a cautionsÂ person. All around me in Lagos, practically everyone in my age bracket is using CBD oil and claimingÂ wonderful results. I consider myselfÂ lucky to be avoided by all but one of the health challenges of senior citizens, glaucoma.
I have read of and heard about many hilarious testimonials thatÂ CBD oil chases away glaucoma.Â One man said last week that after dropping the oil in the eyes of his father for about three weeks, the old manÂ began to see the sharps of palm trees on the grounds of their home in the village. Hitheto, he saw nothing.Â Another woman said she was introduced to CBD oil in the United States for her glaucoma. Soon after, opthamologists there said her eyes were clear. She hopes to reconfirm the report with her Nigerian eye doctor whenever she returns home. In none of these testimonials did I see before and after doctor authenticated report.
How I wish I could beÂ child-like (not childish) in matters such as this whenÂ Mrs Folake Sanusi, who learned the modernÂ uses of herbs from me, gave to me a bottle of locally compounded herbs for cataract and glaucoma which she said took away the glaucoma of a gentleman she knew.Â Prior to using the herb, he had to be led by the hand wherever he went, she said. But when IÂ studied the ingridients and noted that cannabis was among them, I kept the medicine away and told her so. It did not matter to me that from her account, the gentleman could now move about town, unheeded.
In the small study I did thereafter, I discovered that the hemp, which charges the nerves and makes the brain high and the face stoned, does indeed, lower intraocular pressure (IOP), a major cause of vision damage when it is high. But the user would have to â€śhigh upâ€ťno fewer than eight times in one day to control IOP over 24 hours. Quite naturally, no self- respecting eye doctor or any doctor would apply this therapy. For not only may it damage the brain and cause lung degeneration, itÂ may compromise the heart and reduce blood and oxygen flow to the optic nerve, which carries visual impressions from the eye to the brain. Incidentally, poor circulation in the optic nerve is one of the causes of nerve death and blindness.
In response to enquiries about weather CBD oil lowers eyes pressure,Â an Indiana University study was carried out, which showed that this hemp oil had no effect on IOP at low dosages, but raised IOP at higher dosages.
Glaucoma challenged people world wide and their doctors would appear to be in a fix. Surgery and eye drops to managed glaucoma are unpalatable for many challenged person because of their negative sideÂ effects. InÂ many cases, newer and saferÂ therapeutic options become inevitable. In the process, for example, it was suggested that glaucoma was caused by â€śdiabetes of the brainâ€ť and, among doctors there is no serious disagreement that the eyes is the largest store of Vitamin C in the body. In fact, Dr Linus Pauling won the Nobel prize for his work two times on Vitamin C. One of his conclusions was thatÂ large amount of Vitamins C in the eye naturally lowers occular tension. So, the question goes: Do glaucoma challenged persons suffer from Vitamin C deficiency? Did Pauling recommend between 3,000mg and 6,000mg of Vitamin C everyday where many conventional doctors do not prescribe more than 60mg? The concept of â€śdiabetes of the brainâ€ť will be explored some other time. Concepts of the implications of liver and kidney deffiencies we are probably well aware of.
Also, we know Alternative Medicine is making in-roads into glaucoma management. It is clear to many challenged persons that intraocular pressure is not their only challenge. They have to deal also with challenges such as inflammation,Â oxidative stress and damage, insufficiency of antioxidants, poor blood circulation and fragile or incompetent blood vessels.Since this awareness, no fewer than 20 nutritional factors have been researched and found helpful in glaucoma therapies. Among these are Vitamin A; Vitamin B Complex; Vitamin C; Vitamin E; Rutin; Ionic Magnesium; Ionic minerals; Gingko Biloba; Taurine;Â Resveratrol; Grape seed extract; Zinc; Glatathione; Super oxide Dismutase; Essential fatty acids; Alpha Lipoic Acid; Promegrante; Amala (Indian Gooseberry); Goji berry; Bill berry; Blueberry;Â Marigold; Lutein; Zeazanthin; Astazanthin and lately, CBD oil. But of CBD oil, eye doctors are still not speaking with one voice, as they do in respect of surgery and pharmaceutical eye drops.
The ping-pong back and forth-like game of argument is in favour of caution in the use of CBD oil as eye drops to treat glaucoma.Â Â It is like a tumultuous sea intoÂ which the wise swimmer does not plunge without precautions. The following report by Sally Miller, Laura Daily, Emma Leishman, Heather Bradshaw and Alex Straiker represent the thinking of dissenting voices in opthalmology. Their research was founded by the National Institute of HealthÂ of the United States and published online in 2018 as follows:
TetrahydrocannabinolÂ and Cannabinol DifferentiallyÂ RegularÂ IntraocularÂ Pressure
Purpose: It has been known for nearly 50 years that cannabis and the psychoactive constituent -tetrahydrocannabinol (THC) reduce intraocular pressure (IOP). Elevated IOP remains the chief hallmark and therapeutic target for glaucoma, a major cause of blindness. THC likely acts via one of the known cannabinoid-related receptors (CB1, CB2, GPR18, GPR119, GPR55), but this has never been determined explicitly. Cannabinol (CBD) is a second major constituent of cannabis that has been found to be without effect on IOP in most studies.
Effects of topically applied THC and CBD were tested in living miceâ€¦.by using tonometry and measurements of mRNA levels. In addition, the lipidomic consequences of CBD treatment were tested by using lipid analysis.
We now report that a single topical application of THC lowered IOP substantially (28%) for 8 hours in male mice. This effect is due to combined activation of CB1 and GPR18 receptors each of which has been shown to lower ocular pressure when activated. We also found that the effect was sex-dependent, being stronger in male mice, and that mRNA levels of CB1 and GPR18 were higher in males. Far from inactive, CBD was found to have two opposing effects on ocular pressure, one of which involved antagonism of tonic signaling. CBD prevents THC from lowering ocular pressure.
We conclude that THC lowers IOP by activating two receptorsâ€”CB1 and GPR18â€”but in a sex-dependent manner. CBD, contrary to expectation, has two opposing effects on IOP and can interfere with the effects of THC.
Cannabis has a long and storied history tracing back thousands of years. Only recently have we begun to understand how its constituents act in the body.
Tetrahydrocannabinol (THC, THC) is understood to be the chief psycho-active ingredient of cannabis. The year 1971 marked the publication of the first work by Hepler and Frank, demonstrating that cannabis inhalation has a salutary effect on intraocular pressure (IOP). This set in motion a flurry of research to learn the nature of this effect. Remarkably, however, we still do not know through which receptors the principal components of cannabis regulate IOP. It is often assumed that THC does this via cannabinoid CB1 receptors, since CB1 receptor agonists lower IOP, but this has not been demonstrated. Ocular research into the two principal phytocannabinoidsâ€”THC and the noneuphoric cannabidiol (CBD)â€”largely ceased after the early 1980s, well before the first cannabinoid receptor was identified in 1990. CB1 receptors remain the best-characterised cannabinoid receptor and are widely in the brain and eye and regulate important physiological systems such as pain, mood, movement, and memory. But the cannabinoid signaling system consists not only of CB1 receptors, but of CB2,Â GPR18, and GPR11910 and perhaps others, as well as enzymes that produce and metabolise the lipid cannabinoid messengers.
We have determined that at least, three cannabinoid-related receptors (CB1, GPR18, GPR119) regulate IOP in the vertebrate eye. THC activates CB1 and GPR18 and perhaps GPR19. This means that the action of THC may be quite complex.
THC is not the only phytocannabinoid found in cannabis: CBD can be present at quantities comparable to THC and plant strains have now been developed (e.g. Charlotteâ€™s Web) that have a CBD to THC ratio that is heavily skewed toward CBD. Long considered inactive, CBD has shown benefit in clinical trials as an anti-epileptic in Dravetâ€™s syndrome18 and has recently been approved by the United States Food and Drug Administration (FDA) as an anti-epileptic. But CBD is also assigned many other properties, including activity at GPR18 and the cannabinoid-metabolising enzyme FAAH (fatty acid amide hydrolase)21, but CBD may act as a negative allosteric modulator of CB1 signaling. This is significant because this means that CBD may antagonise THC signaling. Three of four studies that have tested CBD for effects on IOP have reported no effect, but the fourth has reported an increase in IOP.24
The current study was an examination of the receptor dependence of the actions of THC and CBD on IOPâ€¦.
THC substantially lowers IOP for at least, eight hours but in a sex-dependent manner. (A) Topically applied THC (5 mM) lowers IOP relative to contralateral vehicle-treated eye in mouse. Effect persists for eight hours. (B) In contrast, females only see an effect of THC at 4 hours.
THC lowers IOP through combined activation of CB1 and GPR18 receptors as noted in the introduction, THC lowers IOP, but the mechanism by which it does this remains undetermined. A preferred hypothesis is that THC lowers IOP via CB1 receptors. We, therefore, tested whether the effect of THC would be absent in CB1 receptor knockout mice. Interestingly, we found that CB1 deletion only partly eliminated the effect of THCâ€¦.This is the GPR18 receptor since, as noted previously, GPR18 can lower IOP in mice and is activated by THCâ€¦. We find that the regulation of ocular pressure by THC and CBD is more complex than previously appreciated. THC acts via a combination of CB1 and GPR18 receptors in a sex-dependent manner, while CBD can both raise IOP and interfere with the effects of THC. The potential of CBD to elevate ocular pressure should be evaluated further as a potential deleterious side effect, particularly with long-term use.
Our finding of sex dependence of cannabinoid regulation of ocular pressure suggests that the current academic view that topical phytocannabinoids are without effect (e.g. the 2014 AAO position statement on cannabis and glaucoma) may be premature. Most of the studies on which this position is based include female subjects, but are underpowered to evaluate a potential sex dependence of effect. However, it should be stressed that the findings presented here highlight the complex endogenous cannabinoid signaling system that can be selectively targeted and harnessed to lower ocular pressure by other means.
For instance, we have shown that it is possible to enhance endogenous cannabinoid signaling by blocking the cannabinoid-metabolising enzyme monoacylglycerol lipase and so lower ocular pressure. Similarly, we have found that activating CB1 directly can achieve the same outcome. Our findings for THC suggest that a dual CB1/GPR18 agonist may prove advantageous. The study of phytocannabinoids such as THC and CBD, but also others derived from the plant, may therefore, point to novel strategies.