Glaucoma hurts over 3 million of people in the U.S., but half of the patients do not know about their condition. However, this eye disease is one of the most common reasons for blindness, as glaucoma may show no symptoms in the early stages. Even after receiving proper treatment, 10% of patients with glaucoma still suffer from the loss of vision that cannot be regained.
Glaucoma is caused by the increase of eye fluid pressure and leads to the damage of the optic nerve and eye vision. This disease can also be provoked by inflammation in the uvea of the eye.
Nowadays, the conventional medicine is not completely effective for glaucoma. Though the treatment includes anti-inflammatory, immunosuppressive, and corticosteroid drugs, these medicines provide only temporary relief. Fortunately, some scientists have found a beneficial link between marijuana and glaucoma after conducting several studies.
So, how does marijuana help glaucoma patients?
The first studies on this issue were carried out in the 1970s, and back then, the findings revealed that cannabis smoking lowered eye fluid pressure (intraocular pressure or IOP) in people with glaucoma. Thanks to THC, one of marijuana's active compounds, our cannabinoid receptors can lower aqueous humor production.
A 2003 study on monkeys showed that even synthetic CB1 receptor agonists lowered IOP in normal and glaucomatous animal eyes. Thanks to these results, scientists created cannabis-infused anti-glaucoma drugs.
Two uncontrolled studies investigated glaucoma and marijuana treatment in the form of weed smoking, along with oral and intravenous methods of THC delivery. The results revealed that all glaucoma patients who consumed weed had reduced IOP.
One more study that was conducted by researchers at the Medical College of Georgia, Augusta, also discovered the same effect of THC on glaucoma patients. According to this study report, 65% of glaucoma patients experienced lowering of IOP after smoking cannabis plant materials. In addition, researchers noticed that the increasing of the marijuana dose led to a greater reduction in IOP.
In addition, marijuana may potentially relieve other symptoms of this illness, such as nausea, pain, vomiting, and inflammation. Though there are no clinical trial studies on marijuana and glaucoma inflammation yet, the anti-inflammatory cannabis agents could serve as a potential treatment for inflammatory glaucoma.
One of the earliest cannabis-related studies on glaucoma discovered that the IOP-lowering effect of marijuana lasted only for 3-4 hours and could not be prolonged with a higher dose of THC. However, glaucoma patients need to keep their eye fluid pressure under control all the time, which requires taking cannabis at least 6-8 times a day round the clock.
This way of treatment is very inconvenient for glaucoma patients, so scientists created topical eye drops infused with THC. Unfortunately, those medications caused eye irritation, and the tears prevented the drug absorption.
Though further studies on drug development are necessary to continue, federal restrictions prohibit this kind of investigation. However, Jamaica has no restrictions on this issue, and glaucoma patients have already benefited from Canasol, a marijuana-infused eye drop formulation available in this country.
Another side effect of cannabis on glaucoma patients is that weed smoking can cause eye reddening, but patients can avoid this effect by inhaling weed via vaporizers.
Besides, along with IOP lowering, weed smoking will also reduce the blood pressure all over the body. Thus, medical marijuana may not be suitable for people with low blood pressure.
Moreover, cannabis consumption may also be contraindicating to patients with certain heart disorders, as well as to those who do not want to experience the psychoactive effect of THC.