cbd oil blurry vision

Cbd oil blurry vision

Like with most medication, the therapeutic use of cannabis or cannabinoids can elicit adverse effects such as tachycardia, dry mouth, blurred vision, vertigo, low blood pressure, panic attack, red eyes or itchy skin.

Similar to its therapeutic effects, the adverse effects related to cannabis use are mostly due to THC and its effect on the CB1 receptor.

Although these effects are generally innocuous and transient, they can be upsetting for uninformed or inexperienced patients.

Here we discuss known adverse effects of cannabis / THC intoxication and, where possible, which countermeasures can be taken.

Unless otherwise stated, the information in this section refers to the “Adverse Effects” section in “Information for Health Care Professionals: Cannabis and the cannabinoids”.

Toxicological effects

Although cannabinoids can exert very strong physical and psychological effects, they are actually quite mild from a toxicological point of view. cannabinoids can be cytotoxic to certain types of cancer cells (for instance see: Gustafsson et al., 2009; Powles et al., 2005) but not under normal physiological conditions.

Similarly, cannabinoids have little or no mutagenic potential under normal conditions and are therefore unlikely to cause cancer for instance.

This results in an unusually high Margin Of Exposure/MOE: the ratio of the lowest dose required for the desired (therapeutic) effect and the dose that elicits adverse or potentially lethal effects. Many therapeutic drugs, but also recreational drugs such as alcohol or nicotine have MOEs 100. Cannabis on the other hand has an MOE >10.000 making it a very safe drug (Lachenmeier and Rehm, 2015).

Please note that although cannabis and cannabinoids are relatively innocuous in themselves, smoking cannabis, like tobacco produces compounds that are cytotoxic and mutagenic (Moir et al., 2008). This is relevant as the majority of therapeutic users prefers smoked/inhaled cannabis (Sexton et al., 2016).

Acute physical effects

· Tachycardia: The most common side effect of cannabis (read THC) consumption is tachycardia. This is transient and dose-related and usually innocuous in healthy young users. However, patients, especially those with a heart condition, should be cautious and contact a physician when in doubt.

· Dry mouth: Cannabis consumption can lead to a dry mouth. This is due to activation of CB1 and CB2 receptors in the submandibular gland (Prestifilippo et al., 2006) and is generally considered innocuous.

· Blurred vision: Cannabis consumption can lead to blurred vision. This is probably a result of THC lowering intra-ocular pressure (which is the basis of the therapeutic use of cannabis against glaucoma). Blurred vision of cannabis use is transient en in itself innocuous.

· Nausea/dizziness: Nausea and dizziness are among the most reported side effects of cannabis (read THC) consumption. The effects are dose-dependent, transient and generally innocuous.

· Low blood pressure: Cannabis consumption can lead to peripheral vasodilation and subsequent low blood pressure. These effects are dose-dependent, transient and generally innocuous.

· Red eyes: Cannabis-induced peripheral vasodilation can cause ‘blood-shot’ or red eyes. This effect is transient and innocuous.

· Itchy skin: Although cannabis is often used to treat itchy skin or similar disorders, itchy skin can also be a side-effect of cannabis use. Itchy skin is transient and harmless.

· Hunger / low blood sugar: Cannabis use is associated with lowered blood sugar levels (Penner et al., 2013) and increased appetite. For this reason cannabis is used to treat Diabetes and anorexia-like symptoms but it can also be experienced and adverse effect. Cannabis-induced low blood sugar is transient and generally harmless.

· Hypothermia: THC in cannabis can produce hypothermia via the CB1 receptor. This effect is transient and generally harmless. Please note that while CBD can revert several effects of THC, it tends to exacerbate THC-induced hypothermia (Taffe et al., 2015)

· Reduced motor control: THC in cannabis can reduce motor control and locomotion. This effect is transient and generally harmless. Please note that while CBD can revert several effects of THC, it tends to exacerbate THC-induced hypolocomotion (Taffe et al., 2015).

Acute psychological effects

· Short-term memory loss: One of the most notable side effects of cannabis use is short-term memory loss. Although this is beneficial for instance for the treatment of posttraumatic stress disorders or for generalized stress relief, it can also be experienced as an adverse effect. Memory loss is induced via THC and CB1 and is transient and innocuous.

· Loss of concentration: As a direct consequence of reduced short-term memory function, cannabis use can also lead to loss of focus or concentration. These effects are mediated via THC and CB1 and are transient in nature.

· Panic attack/paranoia: Although cannabis can be used to treat anxiety or stress, its use can also elicit a panic attack or paranoia. These panic attacks are likely a result of the acute effects mentioned above and are mediated by THC. Cannabis-induced anxiety or paranoia is transient and in itself harmless.


Acute adverse effects of cannabis are transient and are usually easily counteracted with activity, controlled breathing and sugar.

As most adverse effects directly or indirectly result from low blood pressure or low blood sugar, light activity such as walking and consuming sugary food or drinks are often sufficient to abolish these adverse effects in minutes.

Similarly, deep belly breathing can often revert adverse effects such as panic or anxiety in seconds or minutes.

In addition, many effects of THC can be counteracted by CBD although it should be noted that CBD can paradoxically increase the effects of THC by inhibiting its degradation via inhibition of Cytochrome P450 enzymes.

Long-term effects and contraindications

· Carcinogenesis: cannabinoids themselves are not carcinogenic or mutagenic. However, smoking is a popular route of cannabinoid administration and smoking cannabis, like smoking tobacco produces carcinogenic compounds. Interestingly, compared to smoking tobacco, long-term smoking of cannabis actually reduces the risk of cancer in squamous cells lining the respiratory tract in head and neck by approximately 50% (Liang et al., 2009). Vaping or ingesting cannabinoids is likely to greatly reduce the risk of carcinogenesis.

· Respiratory tract: cannabinoids themselves do not negatively influence the respiratory tract. However, smoking is a popular route of cannabinoid administration and smoking cannabis, like smoking tobacco produces pathogenic/carcinogenic compounds. In addition, cannabis smoke tends to be inhaled longer and deeper, resulting in increased tar and carbon monoxide levels compared to smoking tobacco. As a result, biopsies from chronic cannabis smokers often show histopathological changes such as basal cell hyperplasia, stratification, goblet cell hyperplasia, inflammation, basement membrane thickening and squamous cell metaplasia. Vaping or ingesting cannabis is likely to greatly reduce the risk of respiratory tract disease.

· Immune system: The endocannabinoid system is prominently involved in immune regulation. As a consequence, cannabinoids have great regulatory potential in the immune system. Tight regulation of the immune system is crucial to healthy life: an overactive immune system can evoke auto-immune disorders whereas a weak immune system leaves the body prone to infection. THC appears to be mainly anti-inflammatory at low nanomolar concentrations but pro-inflammatory at low micromolar concentrations (Berdyshev et al., 1997). Cannabis use is mostly associated with immunosuppression/anti-inflammatory action, similar to most anti-inflammatory drugs. It is important to realize that chronic cannabis use therefore roughly equates to chronic immunosuppression, which in turn could negatively impact general health.

o Behavior: Cannabis use can influence many types of behavior, including sexual behavior in a dose-dependent way. Both men and women tend to respond positively to occasional low or moderate doses of cannabis with increased sensitivity to touch, increased desire and increased sexual activity. Higher doses or frequency of use can have the opposite effect and inhibit sexual motivation or erectile function for instance.

o Male reproduction: The endocannabinoid system is not just present in the brain (affecting behavior) but in most tissues including reproductive tissues and it can thus influence many aspects of reproductive physiology. An in vitro study showed that THC dose-dependently reduces sperm motility and inhibits the acrosome reaction (Whan et al., 2006). It should be noted though that THC primarily affects motility in ‘poor swimming sperm’. Motility in ‘fast swimming sperm’ is only affected by very high THC concentrations (4.8 μM or ±1500 μg/l plasma), which are not likely to reached after therapeutic or even heavy recreational use of cannabis. Still, cannabis/THC can negatively influence fertility, especially in males that are on the border of infertility.

o Female reproduction: Animal and in vitro studies have shown that cannabis/THC can negatively affect ovulation and successful pregnancy (Kostellow et al., 1980; Yao et al., 2018) but only at very high concentrations, unlikely to be attained in humans. In fact, a systematic review in humans failed to find a negative impact of cannabis use during pregnancy on fetal or child development (Zhang et al., 2017).

· Cardiovascular system: As discussed above, tachycardia and peripheral vasodilation are consistent acute side effects of cannabis use. In healthy young people this is harmless but in elderly people, medical cannabis users or patients with cardiovascular problems this could be relevant. To put things in perspective, smoking cannabis elevates the risk of myocardial infection at population level, but less so then eating a heavy meal. At the individual level, smoking cannabis elevates the risk of heart attack less than exposure to traffic, alcohol, coffee, air pollution, negative emotions, anger, a heavy meal, positive emotions, sex or cocaine use (Nawrot et al., 2011).

· Gastrointestinal system: One adverse effect that is occasionally observed with chronic heavy cannabis use is ‘cannabis hyperemesis syndrome’. Until recently the only remedy was abstinence from cannabis use and taking hot showers. In line with the latter observation, the TRPV1 receptor is now implicated in cannabis hyperemesis syndrome and treatment with topical capsaicin (TRPV1 agonist) appears effective (Dezieck et al., 2017; Moon et al., 2018). Other reported treatments for hyperemesis syndrome are haloperidol (often used as anti-psychotic and anti-emetic) and propranolol (often used against high blood pressure and anxiety) (Jones and Abernathy, 2016; Richards and Dutczak, 2017).

· Central nervous system

o Cognition: Short-term memory loss is a well-known acute effect of cannabis use. Whether chronic cannabis use has a long-term effect on cognition remains controversial and requires more research.

o Motor control: Although cannabis use acutely and negatively affects motor control there is no indication that cannabis can negatively affect motor control on a longer term.

o Mental disorders: Several mental disorders such as depression, anxiety, bipolar disorder, psychosis and schizophrenia have been associated with cannabis use but a causal link was never shown. In fact, several mental disorders are now linked to mutations in the genes underlying the endocannabinoid system / ECS variation, suggesting cannabinoids may be used to treat these very disorders. Regardless, caution is advised for the use of cannabinoids in patients with a history of mental disease.

· Addiction: Like other psychoactive drugs, cannabis (read THC) has the potential to develop psychological dependence and to a degree physical dependence. Whether cannabis or cannabinoid use leads to dependence relies on several factors:

o Genetic passport: every individual has a unique genetic passport, which determines which diseases we are likely to get. Many diseases are now beginning to be recognized as ECS deficiencies, suggesting these can be treated with cannabinoid supplements. Abstinence from cannabinoids is likely to affect people with an ECS deficiency harder than people with a fully functional ECS.

o Route of application: Addiction or dependence is mostly attributed to the smoking of cannabis, especially when mixed with tobacco. Oral or sublingual application of cannabinoids is far less likely to cause dependence. Routes of application that do not cause psychoactive effects (for instance topical application to the skin) are not considered addictive.

o Psychoactivity of cannabinoids: Cannabis / THC is considered addictive mostly because of its psychoactive properties. cannabinoids such as CBD are not psychoactive and are considered to have no abuse potential. In fact, CBD can be used to suppress or counteract the addictive potential of cannabis / THC (Crippa et al., 2013), alcohol (Viudez-Martínez et al., 2017) or tobacco (Morgan et al., 2013).

Berdyshev, E.V., Boichot, E., Germain, N., Allain, N., Anger, J.P., and Lagente, V. (1997). Influence of fatty acid ethanolamides and delta9-tetrahydrocannabinol on cytokine and arachidonate release by mononuclear cells. Eur. J. Pharmacol. 330, 231–240.

Crippa, J. a. S., Hallak, J.E.C., Machado-de-Sousa, J.P., Queiroz, R.H.C., Bergamaschi, M., Chagas, M.H.N., and Zuardi, A.W. (2013). Cannabidiol for the treatment of cannabis withdrawal syndrome: a case report. J. Clin. Pharm. Ther. 38, 162–164.

Dezieck, L., Hafez, Z., Conicella, A., Blohm, E., O’Connor, M.J., Schwarz, E.S., and Mullins, M.E. (2017). Resolution of cannabis hyperemesis syndrome with topical capsaicin in the emergency department: a case series. Clin. Toxicol. Phila. Pa 1–6.

Gustafsson, S.B., Lindgren, T., Jonsson, M., and Jacobsson, S.O.P. (2009). cannabinoid receptor-independent cytotoxic effects of cannabinoids in human colorectal carcinoma cells: synergism with 5-fluorouracil. cancer Chemother. Pharmacol. 63, 691–701.

Jones, J.L., and Abernathy, K.E. (2016). Successful Treatment of Suspected cannabinoid Hyperemesis Syndrome Using Haloperidol in the Outpatient Setting. Case Rep. Psychiatry 2016, 3614053.

Kostellow, A.B., Ziegler, D., Kunar, J., Fujimoto, G.I., and Morrill, G.A. (1980). Effect of cannabinoids on estrous cycle, ovulation and reproductive capacity of female A/J mice. Pharmacology 21, 68–75.

Lachenmeier, D.W., and Rehm, J. (2015). Comparative risk assessment of alcohol, tobacco, cannabis and other illicit drugs using the margin of exposure approach. Sci. Rep. 5.

Liang, C., McClean, M.D., Marsit, C., Christensen, B., Peters, E., Nelson, H.H., and Kelsey, K.T. (2009). A population-based case-control study of marijuana use and head and neck squamous cell carcinoma. cancer Prev. Res. Phila. Pa 2, 759–768.

Moir, D., Rickert, W.S., Levasseur, G., Larose, Y., Maertens, R., White, P., and Desjardins, S. (2008). A comparison of mainstream and sidestream marijuana and tobacco cigarette smoke produced under two machine smoking conditions. Chem. Res. Toxicol. 21, 494–502.

Moon, A.M., Buckley, S.A., and Mark, N.M. (2018). Successful Treatment of cannabinoid Hyperemesis Syndrome with Topical Capsaicin. ACG Case Rep. J. 5, e3.

Morgan, C.J.A., Das, R.K., Joye, A., Curran, H.V., and Kamboj, S.K. (2013). Cannabidiol reduces cigarette consumption in tobacco smokers: preliminary findings. Addict. Behav. 38, 2433–2436.

Nawrot, T.S., Perez, L., Künzli, N., Munters, E., and Nemery, B. (2011). Public health importance of triggers of myocardial infarction: a comparative risk assessment. Lancet Lond. Engl. 377, 732–740.

Penner, E.A., Buettner, H., and Mittleman, M.A. (2013). The impact of marijuana use on glucose, insulin, and insulin resistance among US adults. Am. J. Med. 126, 583–589.

Powles, T., te Poele, R., Shamash, J., Chaplin, T., Propper, D., Joel, S., Oliver, T., and Liu, W.M. (2005). Cannabis-induced cytotoxicity in leukemic cell lines: the role of the cannabinoid receptors and the MAPK pathway. Blood 105, 1214–1221.

Prestifilippo, J.P., Fernández-Solari, J., de la Cal, C., Iribarne, M., Suburo, A.M., Rettori, V., McCann, S.M., and Elverdin, J.C. (2006). Inhibition of salivary secretion by activation of cannabinoid receptors. Exp. Biol. Med. Maywood NJ 231, 1421–1429.

Richards, J.R., and Dutczak, O. (2017). Propranolol Treatment of cannabinoid Hyperemesis Syndrome: A Case Report. J. Clin. Psychopharmacol.

Sexton, M., Cuttler, C., Finnell, J.S., and Mischley, L.K. (2016). A Cross-Sectional Survey of Medical Cannabis Users: Patterns of Use and Perceived Efficacy. Cannabis cannabinoid Res. 1, 131–138.

Taffe, M.A., Creehan, K.M., and Vandewater, S.A. (2015). Cannabidiol fails to reverse hypothermia or locomotor suppression induced by Δ(9) -tetrahydrocannabinol in Sprague-Dawley rats. Br. J. Pharmacol. 172, 1783–1791.

Viudez-Martínez, A., García-Gutiérrez, M.S., Navarrón, C.M., Morales-Calero, M.I., Navarrete, F., Torres-Suárez, A.I., and Manzanares, J. (2017). Cannabidiol reduces ethanol consumption, motivation and relapse in mice. Addict. Biol.

Whan, L.B., West, M.C.L., McClure, N., and Lewis, S.E.M. (2006). Effects of delta-9-tetrahydrocannabinol, the primary psychoactive cannabinoid in marijuana, on human sperm function in vitro. Fertil. Steril. 85, 653–660.

Yao, J.L., He, Q.Z., Liu, M., Chang, X.W., Wu, J.T., Duan, T., and Wang, K. (2018). Effects of Δ(9)-tetrahydrocannabinol (THC) on human amniotic epithelial cell proliferation and migration. Toxicology 394, 19–26.

Zhang, A., Marshall, R., and Kelsberg, G. (2017). Clinical Inquiry: What effects–if any–does marijuana use during pregnancy have on the fetus or child? J. Fam. Pract. 66, 462–466.

Cbd oil blurry vision Like with most medication, the therapeutic use of cannabis or cannabinoids can elicit adverse effects such as tachycardia, dry mouth, blurred vision, vertigo, low blood

CBD Effects on Eyes

Posted on August 19th, 2020

Think about your average day: you probably put a lot of products into or on your body. Some products may seem harmless, but some may have an adverse effect on your body–if not immediately, then gradually, over the years. As we become increasingly conscious of this fact, we also see customers looking for natural products with fewer side effects. And, in this environment, CBD has emerged as a natural product that can address a wide variety of conditions without triggering significant side effects. What is o ne group of people exploring CBD and its possible applications? Individuals who suffer from eye problems such as poor eyesight. Interested in learning more? In this piece, we’ll look at the possible effects of CBD on your eyes. We’ll especially explore the potential of CBD eye treatments, so read on!

What Is CBD?

For years, using the cannabis plant or any of its products was illegal in the United States. Then came the 2018 Farm Bill, which legalized the use of CBD products, so long as they were derived from industrial hemp plants and contained less than 0.3% THC.

CBD, also known as cannabidiol, is mostly touted for its potential health benefits such as alleviating symptoms of anxiety and pain, among others.

The cannabis plant has two main active components: cannabidiol (CBD) and tetrahydrocannabinol (THC); these are just two of hundreds of compounds, known as cannabinoids, contained within the plants. Both compounds produce various benefits, but THC produces mind-altering effects, while CBD doesn’t. Hemp varieties of cannabis plants contain high concentrations of CBD and low concentrations of THC, whereas marijuana plants are the opposite.

Both these cannabinoids interact with a crucial system in your body called the endocannabinoid system (ECS). The ECS is a regulatory system that regulates a host of bodily functions and helps maintain internal balance (homeostasis). Your body creates its own cannabinoids, called endocannabinoids, that strive to restore balance when you’re stressed, depressed, anxious, or feeling pain. Adding external cannabinoids, like CBD, may help expedite this process by supplementing endocannabinoids and boosting their function to restore balance quickly. Now that we have a better understanding of CBD, let’s explore its effects on the eyes.

What Are the Effects of CBD on Eyes?

By 2050, experts predict that the number of people affected by age-related macular degeneration in the United States will increase to more than five million people . For cataracts, that number is expected to hit six million by 2050 . Glaucoma is an example of age-related macular degeneration and can be quite severe when it progresses. So, can CBD be used to help manage symptoms of Glaucoma and other eye problems?

You may be concerned about using CBD if you have eye problems since eye redness is one of the side effects of high-THC products. But here’s the story: you usually develop bloodshot eyes when small blood vessels become dilated. And, since CBD may help decrease blood pressure, it actually tends to constrict blood vessels, reducing redness.

But wait, there’s more: CBD eye drops have shown progress in the treatment of corneal pain and inflammation. The drops appear to trigger the ECS receptors that reduce the pain and eye irritation. Therefore, with more time and testing, CBD eye drops may prove to be an effective treatment for eye inflammation.

CBD’s Anti-inflammatory Properties

CBD also appears to have anti-inflammatory properties. This is beneficial, especially for your eye’s retina, which can become inflamed if you have diabetes or endotoxin pressure. There is a massive correlation between these conditions. When you have low glutathione levels, you can develop both diabetes and macular degeneration. In early studies, CBD has been found to mitigate both these conditions.

CBD and Vascular Endothelial Growth Factor

CBD also appears to inhibit VEGF (vascular endothelial growth factor), a substance that encourages new blood vessel growth that can also lead to tumor development. Many people get regular drug injections in their eyes to suppress VEGF, but early research suggests that a CBD supplement could provide the same function. In fact, a study at Complutense University in Spain found that cannabinoids inhibit VGEF pathways, also slowing tumor growth in mice. Similar effects were also seen in glioma patients.

What Is Glaucoma?

Glaucoma is an eye disease that results in fluid pressure elevations in your eye. If not treated promptly, glaucoma can lead to loss of vision and even permanent blindness. It can occur at any age, but it is more common with older people.

According to the Glaucoma Foundation, around three million people in America currently suffer from glaucoma. Glaucoma is one of the leading causes of blindness in the US and, until recently, people believed that CBD could be used to treat Glaucoma. However, in recent years, eye doctors began warning against this possibility. Why is this so?

CBD Oil Concerns With Glaucoma

According to new research, CBD raises your eye pressure. This is a cause for concern since glaucoma impacts your eyesight because of high-pressure levels. The high pressure from the optic nerve causes damage to the nerve. And since its job is to transmit visual information to the brain, this damage leads to permanent vision loss.

While anyone can develop this eye condition, certain factors increase your risk. These include:

  • Eye injuries
  • Eye surgery
  • Old age
  • Illnesses such as hypothyroidism.
  • Ethnic background. For example, Hispanics, East Asians, and African-Americans are at a higher risk for glaucoma than Caucasians.

There are several forms of glaucoma, including:

Open-Angle Glaucoma

This is commonly known as the “sneak thief of the night,” since it does not show any significant symptoms until vision loss has occurred. It is the most common type of glaucoma, and it develops because your eye’s drainage canals get clogged with time, increasing pressure, which is referred to as IOP. IOP, or intraocular pressure, increases as the fluid fails to properly drain out of the eye.

Angle-Closure Glaucoma

Also known as acute or narrow-angle glaucoma, this sporadic condition occurs when your intraocular pressure rises rapidly without warning. Hence, your drainage canals get blocked and your iris appears less wide than in a person with a healthy eye. Symptoms include headaches, eye pain, blurred vision, and nausea.

Other types of glaucoma include:

  • Traumatic Glaucoma
  • Congenital Glaucoma
  • Secondary Glaucoma
  • Normal-tension Glaucoma
  • Pigmentary Glaucoma
  • Neovascular Glaucoma
  • Iridocorneal Endothelial Syndrome(ICE)

CBD Oil for Glaucoma

As we mentioned earlier, the latest research regarding CBD oil as a treatment for glaucoma is not promising. CBD appears to increase eye pressure–according to a rat study in Indiana, CBD actually raised eye pressure by 18% for at least four hours after drops were administered. In contrast, when testing THC eye drops, researchers noted that eye pressure decreased by up to 30% within eight hours of the dose.

While this research eliminates CBD as a glaucoma treatment, it does establish THC and, by extension, marijuana, as a potentially effective option. Just remember, THC is psychoactive and can give you a high, so many people may prefer to avoid this treatment option.

Benefits of Using CBD Oil

Even though CBD oil won’t alleviate glaucoma symptoms, you can enjoy its other benefits. Many users who suffer from symptoms such as vomiting, nausea, and pain find that CBD offers analgesic and anti-nausea properties, so it provides them with relief.

Also, in certain cases, studies show CBD lowering intraocular pressure in the eye, although more research is necessary given the conflicting findings.

As research progresses, however, we may find that CBD can lower your IOP and help protect the retinal cells. CBD may also help alleviate fear and anxiety before or after eye surgery. At this time, however, CBD eye drops are still a work in progress. Do not attempt to switch or replace your prescribed eye medications without talking to your doctor.

What is one group of people exploring CBD and its possible applications? Individuals who suffer from eye problems. So what are the effects of CBD on eyes?