Due to the growing legalization of medical marijuana debates, there have raised many questions over the uses of Marijuana for the treatment of Glaucoma. It has also caused many patients who use marijuana for recreational use to talk to their ophthalmologist about their own prevention of glaucoma.

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First, we have to understand the background….

In terms of treatment of glaucoma, a patient MUST have 24 hour coverage of eye pressure lowering effects. Basically, if a patient were to have Glaucoma, and they were to use an eye drop that lowers the eye pressure for only 8 hours, that means that the patient is still walking around with elevated eye pressure for 16 hours during the day. That not only is not good coverage, but it is actually MORE dangerous than not treating it at all. You see, under-treating eye pressure causes even greater fluctuations in eye pressure than had it been left alone. This is extremely dangerous for Glaucoma patients.

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  1. What is Glaucoma? Glaucoma is an eye disease that causes progressive, painless visual loss, which if goes undetected, will lead to total blindness. It is the #2 cause of irreversible blindness in the USA. There are many risk factors which can lead to or even worsen Glaucoma, however the most popular risk factor is an elevated eye pressure. This is why billions of dollars or research has lead to multiple surgical procedures and countless medications, which are aimed strictly to lower eye pressure.
  2. What is Marijuana? Marijuana is a natural plant that grows in the ground. It has multiple medicinal/recreational uses which are derived from 2 active ingredients in Marijuana. Active Ingredient #1- THC (tetrahydrocannabinol) THC is the portion of the Marijuana plant that causes euphoria, or “getting high” sensation, slowed reflexes, increasing hunger, and in some instances hallucinations. Active Ingredient #2- CBD (cannabidiol) CBD causes relaxation, and pain relief
  1. How has Marijuana been linked to Glaucoma? In 1971, a study came out showing that marijuana lowers the eye pressure. After this study, marijuana has been labeled as the natural miracle plant for treatment of glaucoma. The only problem is, the study never stated which active ingredient lowered the pressure, and it also did not state how long the effect would last.

Now that you have the background, lets tackle the newest study done at the University of Indiana in 2018. They tested the effects of each one of ingredients (THC and CBD) on eye pressure when used alone, as well as when used together. What they found was astonishing, but shocking.

 They tested an eyedrop with CBD, the component of cannabis that does not get you stoned, and they found that it RAISED EYE PRESSURE by 18 percent for at least four hours after the drops were instilled. They also tested THC, the component that does get you stoned, and they found that drops containing only THC decreased eye pressure by up to 30 percent within eight hours. They then tested an eye drop with BOTH CBD and THC and found that due to the counteracting effects of CBD vs THC, marijuana does lower eye pressure, but for a very short amount of time.

What does this mean? This means that although CBD has many medicinal positive effects, it should be used in extreme caution! Patients with Glaucoma should NOT use CBD as it will likely increase the patient’s eye pressure. If used for an extended period of time, it can lead to glaucoma in patients at risk, who normally would not have developed glaucoma.
While it’s true that smoking marijuana can reduce pressure inside the eye, it remains a suboptimal treatment because people with glaucoma require 24-hour pressure control to prevent vision loss. You would need to smoke marijuana 8 to 12 times a day, every single day of your life; a treatment regimen that would make it difficult to hold down a job, drive, or function, not to mention the potential cost. The potency of marijuana also varies considerably. It is also unknown yet how it interacts with other medications. One study showed that some people can build up a tolerance to marijuana’s eye pressure lowering effects.

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This is the reason why the American Academy of Ophthalmology and the American Glaucoma Society do not recommend using marijuana for treatment of Glaucoma. However, these studies released by the University of Indiana have had eye opening detrimental effects of CBD on eye pressure. CBD is readily available, legally, at pharmacies and the internet without prescriptions, but please use it in caution and speak to your eye doctor about whether the benefits you are seeking from CBD can be used safely with YOUR eye status. YOUR eye is not the same as your friend, parent or sibling’s eye, so please don’t use what an eye doctor tells your friend/parent/sibling and assume it pertains to you too.