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Research findings from the 1970s show that Cannabis, commonly known as marijuana, reduces intraocular pressure, a key contributor to glaucoma. Since then, better and more effective medications and treatments have been developed, which have the potential to halt and possibly reverse the progress of glaucoma.

Marijuana, the dried leaves and stems of the Cannabis sativa plant, has a long history of use as a recreational substance due to its psychotropic effects. Whether smoked, eaten (often in baked goods), or consumed as a tea, its significant extracts include ∆-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC, the active ingredient responsible for the sought-after ‘high’ in recreational users, can be smoked, vaporized, or taken orally.

The mechanism by which marijuana reduces eye pressure is not entirely clear. However, clinical data suggests it may suppress aqueous fluid production and increase fluid outflow from the eye, along with potential neuroprotective effects.

FDA-approved THC-based medications, like Marinol ® (active ingredient: dronabinol, a synthetic form of THC), are used to manage nausea and stimulate appetite in cancer patients undergoing chemotherapy, as well as those with wasting diseases like AIDS. CBD, another extract (among an estimated 80 cannabinoids in marijuana), has approval for treating a form of childhood epilepsy. THC and CBD, along with other cannabinoids, are formulated in some medications to address spasticity and neuropathic pain.

Safety and Side Effects of Using Marijuana for Glaucoma

While marijuana contains many botanical compounds, it’s these additional elements that can lead to problems and adverse effects when smoked or consumed.

Short-term effects, besides the ‘high,’ include reduced blood pressure, increased heart rate, anxiety, and paranoia. Users may experience red, dry eyes with constricted pupils that are sensitive to light.

Considering that reduced blood flow to the eye is a risk factor for glaucoma, the blood pressure-lowering effects of marijuana might counteract the benefits of lowering eye pressure.

Long-term use (over years) can impact cognitive functions such as thinking, memory, and learning. Frequent smoking can irritate the lungs and increase the risk of substance abuse disorder. It’s advised against use during pregnancy, as it has been associated with behavioral issues in children (Ref: Marijuana and Public Health CDC.).

Who Should Consider Marijuana for Glaucoma Treatment?

Studies have shown that THC and other cannabinoids can “significantly” reduce eye pressure in both glaucoma patients and healthy individuals. However, while it was discovered 40 years ago that smoking marijuana lowers eye pressure (a chief glaucoma risk factor), newer therapies have since been developed without the side effects of marijuana use.

Currently, there are no cannabinoid medications approved for glaucoma treatment. Both the American Academy of Ophthalmology and the American Glaucoma Society do not recommend marijuana for glaucoma treatment.

Dosages of Cannabinoids

The effectiveness of cannabinoids depends on the dosage but is generally short-lived, lasting 3 to 4 hours. This necessitates frequent consumption, which isn’t ideal for maintaining consistent ocular pressure control. Modern pharmaceutical treatments, which are effective without such side effects, typically require only one or two doses per day.

The future of glaucoma treatment with marijuana calls for more clinical research to isolate the eye pressure-lowering components (cannabinoids) for use in a glaucoma treatment with fewer adverse effects.

Examples of contemporary eyedrop medication for glaucoma, used once or twice a day – as directed.

In the End…

Marijuana shows promise in lowering eye pressure, its use for glaucoma treatment remains complex. Current FDA-approved medications offer effective alternatives with fewer side effects. As research continues, the hope is to isolate the beneficial components of marijuana for glaucoma management, paving the way for safer and more targeted treatments in the future.