If you are thinking of using CBD oil for glaucoma, you should think again. THC-containing products are a far more effective treatment for the disease. Change in Refractive Error Associated With the Use of Cannabidiol Oil This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits
CBD and Glaucoma: Does It Help Reduce Eye Pressure?
However, when used in conjunction with other cannabinoids, CBD for glaucoma can work as an effective treatment.
There’s a lot of false information out there that suggests CBD alone is an effective way to treat the condition. This information can be dangerous to someone that actually suffers from the disorder.
In this article, we’ll be looking at the facts and helping you understand how certain cannabinoids can treat glaucoma.
What are the Effects of CBD on the Eyes?
On a normal healthy person, CBD has no known negative effects on the eyes however that isn’t the same for people with glaucoma as some studies suggest.
Using CBD alone in the form of an isolate can be detrimental if you have glaucoma. One study from Indiana University found evidence to suggest that CBD raises the pressure inside the eye . If this is true, CBD could worsen the primary underpinning of the disease.
The study was conducted on mice and found that CBD raised eye pressure by 18 percent. This lasted for up to four hours after the CBD was administered.
As you will know if you or someone close to you suffers from glaucoma, high eye pressure is a primary risk factor for people with the disease. High eye pressure can quicken the damage to the optic nerve at the back of the eye which could ultimately lead to blindness.
The best way to fight glaucoma is to lower eye pressure as much as possible. This will slow down any permanent damage that may be taking place. With this in mind, CBD alone isn’t recommended as a treatment for the disease.
If you were hoping to use CBD for glaucoma, do not fear, all hope is not lost. Other cannabinoids such as THC (tetrahydrocannabinol) have been found to lower eye pressure and have a positive effect on glaucoma.
When a true full-spectrum product is used to treat glaucoma CBD can actually benefit you. As we mentioned, CBD alone can be detrimental to the disease however when used in conjunction with THC it can have some positive effects.
Is THC Better for Glaucoma Than CBD?
THC as a singular cannabinoid certainly helps people with glaucoma more than CBD alone.
Numerous studies show that both delta 9-THC and delta 8-THC have a significant effect on optic nerve health. Evidence shows that THC not only reduces intraocular pressure but also helps to protect against neuron damage.
Research shows that both THC and CBD can protect against cell damage due to elevated levels of glutamate. CBD can indirectly help glaucoma as long as it is combined with other cannabinoids in a balanced true full-spectrum product.
Let’s take a look at how THC and CBD can positively impact eye health and be used to treat glaucoma.
THC Reduces Intraocular Pressure
Lowering eye pressure is an important factor in treating glaucoma. From as early as the 1970s, it has been common knowledge that THC lowers intraocular eye pressure. So, how does it work?
THC interacts with the receptors in the body’s endocannabinoid system. Studies show that THC reacts with receptors in the eye .
CB1 receptors have been found in the ciliary epithelium, the corneal epithelium, and the endothelium of the eye. It is believed that THC interacts with these receptors and as a result, intraocular pressure is lowered.
THC Decelerates Vision Loss
THC has been found to decelerate vision loss according to a study published in Experimental Eye Research .
The study tested the effects of THC on rats with retinitis pigmentosa — a genetic eye disease that leads to blindness. After a 90 day treatment, the rats that consumed the cannabinoid gained better scores on vision tests.
The THC rat group also acquired 40 percent more photoreceptors than the untreated control group. Those are some impressive results.
The potential that THC alone has to slow down blindness is staggering.
THC & CBD Support Optic Nerve Health
THC and CBD together have been found to support optic nerve health . People with glaucoma have an excess of glutamate — a major neurotransmitter in the eye.
In glaucoma sufferers, this neurotransmitter accumulates in the retinal region and damages cells, eventually leading to vision loss. This is called glutamate-induced neurotoxicity.
THC and CBD help protect against the condition, potentially preventing blindness and prolonging vision loss.
CBD Oil and Glaucoma
Most commercially available CBD oils will not help glaucoma, in fact, they could have an adverse effect. Even CBD oils labeled as full-spectrum aren’t going to cut it when it comes to this disease, as they simply contain too much CBD and not enough THC.
The best oil for glaucoma is a true full-spectrum THC-containing cannabis oil. Both delta 9-THC and delta 8-THC can be used to treat glaucoma with excellent results. Finding an oil that contains both cannabinoids is the best way to treat the disease.
Delta 9 and delta-8 THC are psychoactive so they will get you “high.” This is something to keep in mind if you are looking for cannabis to treat glaucoma because unfortunately, this side effect is unavoidable.
Research shows that delta 8-THC is slightly less psychoactive than delta 9 but you will still experience a “high.”
If you’re looking for a glaucoma treatment that helps but you are put off by the thought of being overly intoxicated, a delta 8-THC oil or tincture is worth trying.
If you can deal with the psychoactive effects of full-spectrum THC-containing cannabis oil, it will benefit the disease massively. Just remember not to operate any machinery or vehicles while medicated.
Is THC-Containing Cannabis Oil Legal?
Any cannabis oil that contains over 0.3% delta 9 THC is illegal under federal law, however, state law allows it depending on the state that you reside in.
Cannabis products, for the most part, are also banned across Europe and the UK, so make sure you know the law in your area.
Delta 8 THC is still technically legal under federal law, which means it is unbanned across the US. Regardless, make sure to check your state law if you are unsure of your local restrictions.
In most of Europe and the UK, any form of THC is banned by law, making delta 8 THC illegal as well.
Check the law in your country and region if you are planning on using THC for glaucoma. Cannabis is becoming more accepted as a medicine. Even in banned countries such as the UK, THC-containing products may be available on prescription from your doctor.
CBD vs. THC For Glaucoma
There are many benefits to using THC and CBD for glaucoma. Both cannabinoids have their place in treating the disease, but like any medication, there are some downsides.
If you have glaucoma and are considering using cannabis oil to treat it, you will have to weigh up the pros and cons. Doing this will help you understand whether this route is going to work for you.
- THC decelerates vision loss
- It reduces intraocular pressure
- Supports optic nerve health
- Analgesic qualities — can reduce pain
- Aids in the support of optic nerve health when used alongside other cannabinoids
- Vaso-relaxant — increases the level of ocular blood flow
- Anti-inflammatory — can reduce some side effects of glaucoma
- Analgesic qualities — can reduce pain
- Anti-nausea qualities — can help reduce the side effects of other glaucoma meds
- Is psychoactive — will get you “high” (can become an inconvenience)
- Only effective for three to four hours before another dose is needed
- High-quality oils and extracts are expensive
- Illegal in some states and across Europe
- When used alone it can raise intraocular pressure
- Must only be used alongside the psychoactive cannabinoid THC
How to Use CBD Oil for Glaucoma?
The best way to use CBD for glaucoma is in a true full-spectrum product that has a cannabinoid profile as close to the raw plant as possible. A delta 8 THC oil or tincture is another good option to consider.
You can use cannabis oil in a variety of ways to treat glaucoma. Full-spectrum oils are available in many forms. You will find pure oils, vape products, tinctures, capsules, gummies, and sprays.
You need to treat glaucoma 24 hours a day and unfortunately, the intraocular pressure-reducing qualities of THC don’t last long. You’ll need to medicate periodically throughout the day.
Studies from the National Eye Institute show that THC does lower IOP (intraocular eye pressure) by up to 30 percent. The downside is, IOP levels only stay this low for three to four hours.
If you’re going to use cannabis oil or another THC-containing product to treat glaucoma, you will need to medicate every three to four hours. This is great during the day but unless you plan on waking up every few hours at night, it is not so good.
Intraocular eye pressure levels increase during the night. This is mostly down to fluid distribution leading to choroidal vascular congestion when lying flat during sleep. This is a problem if you plan on using cannabis alone to treat glaucoma.
The answer is to use cannabis oil alongside other forms of glaucoma medication such as bimatoprost eye drops and/or acetazolamide pills.
Although you should continue using your prescription glaucoma meds, you may be able to reduce your intake and side effects by using cannabis oil alongside them.
How Much CBD Oil Should I Take for Glaucoma?
How much cannabis oil you take for glaucoma depends on a lot of factors.
Usually, one to two drops of cannabis oil under the tongue is sufficient for lowering intraocular eye pressure. Keep in mind, the strength of the oil you are using will ultimately affect the dosage.
If you are new to cannabis, start small with a 10 mg dose and increase once you know how you react to it. People react differently to THC so don’t be put off if you feel the need to increase or decrease your dose.
Speak to your local dispensary or get some advice on dosages for the specific oil you will be using.
No matter the strength or dosage you are taking it is important to remember to medicate every three to four hours to maintain low eye pressure.
Final Thoughts — Should You Use CBD for Glaucoma?
As you now know, CBD alone is not an effective treatment for glaucoma. The cannabinoid by itself can increase eye pressure which is a less than desirable effect if you have the disease.
If you have glaucoma, you should do your best to avoid CBD oils and stick to full-spectrum oils that are high in THC.
Glaucoma can’t be cured yet, but it can certainly be controlled. With the right treatment, the progression of vision loss can be slowed down dramatically and even stopped entirely.
People that suffer from glaucoma can lead perfectly normal lives with the right treatment. Cannabis can be a large part of that treatment and help you get back on the path to normality.
Cannabis oil or any other THC-containing products should not be used as a primary treatment for glaucoma. Any prescription medication should still be taken to reduce vision loss and prevent optic nerve damage.
Always check with your doctor before using cannabis alongside any existing medication.
References Used In This Article
- Miller, S., Daily, L., Leishman, E., Bradshaw, H., & Straiker, A. (2018). Δ9-Tetrahydrocannabinol and cannabidiol differentially regulate intraocular pressure. Investigative ophthalmology & visual science, 59(15), 5904-5911.
- Straiker, A. J., Maguire, G., Mackie, K., & Lindsey, J. (1999). Localization of cannabinoid CB1 receptors in the human anterior eye and retina. Investigative ophthalmology & visual science, 40(10), 2442-2448.
- Lax, P., Esquiva, G., Altavilla, C., & Cuenca, N. (2014). Neuroprotective effects of the cannabinoid agonist HU210 on retinal degeneration. Experimental Eye Research, 120, 175-185.
- Hampson, A. J., Grimaldi, M., Axelrod, J., & Wink, D. (1998). Cannabidiol and (−) Δ9-tetrahydrocannabinol are neuroprotective antioxidants. Proceedings of the National Academy of Sciences, 95(14), 8268-8273.
Livvy is a registered nurse (RN) and board-certified nurse midwife (CNM) in the state of New Jersey. After giving birth to her newborn daughter, Livvy stepped down from her full-time position at the Children’s Hospital of New Jersey. This gave her the opportunity to spend more time writing articles on all topics related to pregnancy and prenatal care.
Change in Refractive Error Associated With the Use of Cannabidiol Oil
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Cannabinoid (CBD) products have gained popularity since their legalization in 2018, causing a plethora of unregulated CBD products to be sold in the United States. These products are available in various combinations for topical and oral consumption, claiming credit for potentially improving various diseases. In this report, we present a newfound case reporting a shift in refraction that may be associated with the regular use of CBD oil supplements.
A 57-year-old woman with a history of diabetes mellitus type 2, hyperlipidemia, obstructive sleep apnea, with no change in medications, diet, or lifestyle was found to have a hyperopic shift in vision with the recent daily addition of CBD oil intake.
This case report highlights the possible association of CBD oil and vision changes after regular consumption of CBD oil in an otherwise stable patient. Further study is required to understand the mechanisms of CBD oil-associated shift in refractive error. Because the patient is diabetic and the refraction shift was hyperopic, other etiologies, such as un-noted lenticular change, cannot be ruled out. CBD products are unregulated and marketed in many mixed forms, and thus can cause unforeseen effects on susceptible individuals. This warrants Food and Drug Administration (FDA) regulation of such products and extensive research before considering them for therapeutic usage.
Cannabis, or marijuana, has been utilized in psychogenic therapy for hundreds of years. Over the past few decades, it particularly has a newfound use in pain medicine, neurology, oncology, gastroenterology, and ophthalmology [1-2]. Recently, cannabinoid (CBD) oil has been immensely used as supplements and in beverages after the passing of the Hemp Farming Act (HFA) in 2018, which legalized hemp-derived products in the United States. This has allowed commercial companies to produce and sell unregulated CBD oil products without US Food and Drug Administration (FDA) approval. Each product of CBD is potentially unregulated as an uncontrolled substance with varying concentrations, variance in the quality of hemp varieties, and lipid oxidation profiles . Without regulation and medical guidance, CBD oil products can cause severe side effects . We present an isolated case of a patient who reported gradual improvement in myopic vision after starting cannabidiol (CBD) oil for the past few weeks and reversal to original myopic refraction after the discontinuation of CBD oil. To our knowledge, this is the only case report that presents a hyperopic shift in association with cannabidiol oil intake in the English language ophthalmic literature.
A 57-year-old, white female presented to the optometry clinic with eye strain and a gradual decrease in her vision for the last three weeks. She reported her eye strain was somewhat relieved after she removed her glasses. Her medical history was remarkable for obstructive sleep apnea, hyperlipidemia, and polyneuropathy secondary to continued uncontrolled type 2 diabetes (most recent hemoglobin A1c = 12.8%), osteopenia, and restless legs syndrome. Her social history included cigarette smoking (seven cigarettes a day with a five-pack-year history). She denied the use of alcohol or recreational drugs. Her ocular history pertaining to trauma or any surgery was negative. Additionally, she noted having no other symptoms such as headache, dry eyes, double vision, vision loss, spots, or threads in her vision.
On examination, her visual acuity (VA) with her habitual glasses was 20/60 in the right eye (OD) and 20/70 in the left eye (OS), pin holed to 20/40 OD and 20/40 OS. The pupils were round and reactive to light OU, with no relative afferent pupillary defect. External examination, extraocular muscle movements, and counting finger visual field tests were normal. Her intraocular pressure was 16 mmHg in the right eye and 17 mmHg in the left eye, measured with a tonopen. The dilated fundus examination revealed rare cotton wool spots, microaneurysm, dot-blot hemorrhages, and vascular attenuation consistent with moderate, non-proliferative diabetic retinopathy in both eyes without any signs of macular edema (Figure (Figure1). Her 1 ). Her optic cups appeared normal with no signs of glaucoma. Given her decrease in vision and clinical presentation of non-proliferative diabetic maculopathy, we decided to run a macular optical coherence tomography (OCT) scan (Figure (Figure2). 2 ). The fovea showed a normal contour, no central macular edema, and an average central retinal thickness of 275 µM OD and 273 µM OS.
Color fundus photographs of the right eye (A) and left eye (B) with non-proliferative diabetic retinopathy
Cotton wool spot (thin arrow), dot blot, and exudates (thick arrow)
Fovea shows normal contour with no central edema; average central macula thickness of 275 µM OD and 273 µM OS
On refraction, her manifest refraction had shifted from her habitual of -2.25 D sphere to -0.75 D in the right eye and from a habitual of -2.00 D to -0.75 D sphere in the left eye. Her new corrected VA in the right eye was 20/25 and 20/25 in the left eye, and a new pair of prescription glasses were made. This new information of hyperopic shift led us to systemically review her medications for possible associations.
Her medications included multivitamins, dulaglutide, canagliflozin, sitagliptin-metformin, lisinopril, gabapentin, pramipexole, clotrimazole-betamethasone, cyclobenzaprine, glucosamine sulfate, zolpidem, cetirizine, ranitidine, and magnesium oxide. In addition to the above, over the past eight weeks, she had started taking 750 mg of peppermint-flavored Full Spectrum CBD Oil (HempWorx, MyDailyChoice, Las Vegas, Nevada), 12 drops twice a day for restless leg syndrome. The patient reported having improved sleep but associated gradual blurry vision which made her visit the optometry clinic.
At the three and six-month follow-ups, the patient’s refraction was re-assessed, and her improved VA remained stable with no report of blurry or worsening of vision, headache, or eye strain. The patient continued to take CBD oil regularly as before and claimed her improved vision to the intake of CBD oil. The patient additionally reported no significant change in diet, lifestyle, and medication and reported her new glasses to be “perfect.” At the nine-month tele-visit follow-up, the patient ran out of CBD oil and thus had to stop taking CBD oil for three to four weeks. Within three weeks of stopping the CBD oil, the patient again noted a gradual worsening of her vision. The patient tried her old prescription lenses with -2.25 OD and -2.00 OS refractive error correction and reported seeing clearly. She had reverted to her original myopic state after stopping the CBD oil.
Based on the patient’s history and ocular examination, there is a clear hyperopic shift in the patient’s refraction after initiation of the CBD oil supplement and its reversal after stopping the CBD oil. Her refractive error remained unchanged while she was on the CBD oil supplement and attests to the use of CBD oil regularly as she finds relief from her restless leg syndrome. Possible etiologies of her refractive shift include the patient’s status of diabetes mellitus type 2, medication history, and her recent use of CBD oil .
Based on the exam and imaging, our patient had classic diabetic retinopathy (last HbA1C 12.8%) with no significant macular edema. Myopic shifts in vision are reported in about 4% of the diabetic patient population, however, hyperopic shifts are reported even less often. Myopic and hyperopic shifts have been traditionally thought to be due to hyperglycemia and hypoglycemia, respectively, but recent studies have suggested hyperopic shifts can also occur due to hyperglycemia . The hyperopic type of refractive shift in an uncontrolled diabetic patient has been mostly attributed to the changes in the refractive index of the lens due to fluctuations in water distribution [7-9]. In the current patient, the timing of the onset of refractive change, along with her chronic state of uncontrolled diabetes (based on her last three years of high Hb A1C numbers), is unlikely due to her hyperglycemia, especially when associated with the change in vision over three weeks of time after the initiation of CBD oil. Interestingly, her refractive shift was stable while she was on the CBD oil and reverted to her original myopia after she stopped taking the CBD oil.
The association of vision change after the start of the CBD oil cannot be ruled out as one of the plausible causes. The authors are aware that this is an isolated case report where the patient clearly related her gradual change in vision after starting the CBD oil drops twice daily for six weeks. While the mechanism by which CBD oil affects refractive error is still an area for further exploration, CBD has been shown to regulate blood flow in retinal vessels and help in reducing neurotoxicity, oxidative stress, and blood-retinal barrier breakdown. The possible inhibition of p38 MAP kinase may also be a possible theory for the hyperopic shift [10-12]. Effects of cannabinoids on the anterior segment of the eye are also multiplex, and some studies indicate decreased corneal endothelial density . Further studies will be needed to assert the findings from this isolated presentation of the case to better understand the role of CBD oil in refractive errors of the eye, especially in a diabetic condition.
We present a case where a woman taking CBD oil orally for six weeks on a regular basis was found to have an improvement in myopia. In addition, her hyperopic shift reverted to her original myopic vision once she stopped taking her CBD oil. To our knowledge, this is the first case of CBD oil in association with a hyperopic shift. The mechanisms by which her VA improved are uncertain and can vary from possible corneal changes to retinal vasculopathy. Hyperopic shift due to her diabetes and antihistamine medications are a possibility, although unlikely, due to her established disease and chronic medication use. There is no previous case report of such an association in hyperopic shift and no prior head-to-head study looking at specific types of CBD oils and other forms of cannabinoid products. This novel isolated incident between CBD oil and change in VA requires additional, controlled, blinded research for further applicability.
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