While marijuana does lower IOP, it has major drawbacks as a treatment for a chronic, long-term, disease like glaucoma:
As marijuana use becomes more accepted and increasingly legalized, glaucoma patients frequently ask if marijuana can really treat glaucoma. We need to explain some truths and dispel some myths.
Marijuana’s ability to lower intraocular pressure (IOP) was discovered in the 1970s. Elevated IOP is the major risk factor for developing glaucoma and for the progression of glaucoma. Treatment is focused solely on reducing IOP. Many have wondered whether marijuana could be used as a therapy to lower IOP and prevent glaucoma from getting worse or causing blindness.
Are There Long-Term Side Effects of Marijuana?
New evidence has emerged showing that parts of the cannabis plant, specifically cannabidiol (CBD), the non-intoxicating, trendy component, may actually worsen glaucoma symptoms. Researchers at Indiana University published a study in the journal Investigative Ophthalmology & Visual Science that shows CBD increases pressure in the eye. This is problematic, they say, considering that CBD has become such a household name in American culture that many people, some of which may have or be at risk for glaucoma, are using it haphazardly as a natural, harmless medicine. But in reality, CBD could be destroying their overall eye health.
Marijuana is legal for medical use in 30 US states and for recreational use in 9 US States. It’s legal across Canada for recreational use. Despite the relaxed attitude around marijuana, it is still classified by the federal Drug Enforcement Agency as a Schedule I controlled substance (the same category as heroin and LSD ).
Marijuana can cause permanent lung damage when smoked, and possible permanent adverse effects on cognition and mental health. With regular use, tolerance to the eye pressure-lowering effects develops, meaning that increasing drug levels would be required to prevent progression of glaucoma. Moreover, lack of regulation and quality control makes efficacy and safety of marijuana unpredictable. Research efforts to develop THC eyedrops that can effectively lower eye pressure while minimizing side effects are being studied, but have not yet been successful.
For these reasons, smoking marijuana or using CBD oil is not recommended as a medical treatment for glaucoma. If you use marijuana or CBD oil, let your ophthalmologist know since it may have an impact on your eye pressure readings. Also, it is very important to continue the glaucoma treatment recommended by your ophthalmologist. This treatment and regular monitoring can help you maintain your vision for the rest of your life.
Patients and methods: A randomized, double-masked, placebo-controlled, 4 way crossover study was conducted at a single center, using cannabis-based medicinal extract of Delta-9-THC and CBD. Six patients with ocular hypertension or early primary open angle glaucoma received a single sublingual dose at 8 AM of 5 mg Delta-9-THC, 20 mg CBD, 40 mg CBD, or placebo. Main outcome measure was IOP. Secondary outcomes included visual acuity, vital signs, and psychotropic effects.
Purpose: The purpose of this study was to assess the effect on intraocular pressure (IOP) and the safety and tolerability of oromucosal administration of a low dose of delta-9-tetrahydrocannabinol (Delta-9-THC) and cannabidiol (CBD).
Results: Two hours after sublingual administration of 5 mg Delta-9-THC, the IOP was significantly lower than after placebo (23.5 mm Hg vs. 27.3 mm Hg, P=0.026). The IOP returned to baseline level after the 4-hour IOP measurement. CBD administration did not reduce the IOP at any time. However, the higher dose of CBD (40 mg) produced a transient elevation of IOP at 4 hours after administration, from 23.2 to 25.9 mm Hg (P=0.028). Vital signs and visual acuity were not significantly changed. One patient experienced a transient and mild paniclike reaction after Delta-9-THC administration.
Conclusions: A single 5 mg sublingual dose of Delta-9-THC reduced the IOP temporarily and was well tolerated by most patients. Sublingual administration of 20 mg CBD did not reduce IOP, whereas 40 mg CBD produced a transient increase IOP rise.
If you have open-angle glaucoma, the drainage canal entrances are working properly, but there will be a clog deep inside the canals. The condition develops slowly and you may not experience any loss of vision for years. If you can catch it early, medication can help treat the condition.
There are various types of medicated eye drops that are specifically formulated to treat glaucoma, including:
Also known as the ‘silent thief of sight’, glaucoma is an eye disease that results in elevations in fluid pressure in the eye. If you fail to treat it in time, it can cause loss of vision and even permanent blindness.
Also called narrow-angle or acute glaucoma, this condition is relatively rare and involves intraocular pressure that rises rapidly and without warning. The drainage canals become blocked because the iris is not as wide as it is in a healthy eye. The iris’ outer edge bunches up over the canals when the pupil enlarges too fast or too much (such as when you suddenly enter a dark room from a bright outside area).
It is especially prevalent amongst African-Americans, who are up to eight times more likely to become blind from glaucoma than Caucasians. Despite all of the above, a 2002 Prevent Blindness America Survey uncovered a shocking fact: 30% of people had never heard of glaucoma!