This eye disease can result in partial or complete loss of vision, damage to the optic nerve, and is the leading cause of blindness in our country. Glaucoma is often included as a medical condition listed in those states that have medical cannabis, and we can see if this listing is justified or warranted, and explore the issues with glaucoma and cannabis that are known to date. In the 1970s glaucoma was the first qualifying condition used for medical states with cannabis, and this fact is somewhat widely known by most citizens in the US.
Often with this disease, there is increased intraocular pressure, which cannabis has been shown in most studies to lower this pressure by perhaps 25-30%. This pressure in patients with glaucoma is elevated due to improper drainage of the aqueous humor (one of the fluids in the eye), and resulting damage to the optic nerve due and retinal cells from the increased pressure can result. This can be checked readily by the ophthalmologist with a quick screening where they gently touch or probe your eyeball and directly measure the pressure. It is postulated that the THC has the most direct effect on pressure, although CBD may also offer some long term protective effects as well. A major stumbling block in treatment is the negative side effects that naïve users find objectionable from the psychoactivity of the THC. Also, the effect lasts only several hours requiring repeated dosing, or alternative methods of ingestion, designed to minimize psychoactivity. A sublingual dose of 5 mg THC four times a day has been shown to be effective, however in some naïve patients who have never used cannabis, this dose may take a few weeks to achieve, this is to avoid adverse or unwanted effects, and to ramp up THC gradually to let your body adapt to it. Inhaled or vaporized cannabis did not seem to be as effective as the use of a tincture sublingually. CBD by itself did not show any effectiveness in reducing pressure, and in high doses increased it. However, the CBD is shown to exert a neuroprotective effect not related to a reduction in pressure but to the general support, it offers as a neural regulating agent and supporter of nerve cell nutrition and function.
The mechanism of action is believed to be under the control of the CB1 receptors located in the eye itself, as the synthetic THC analog WIN55,212-2 that stimulates this receptor similar to THC causes the pressure to drop. Reduced intraocular pressure (IOP) is one hopeful result from treatment, and can result in less damage and slow the progression of the disease.
In general, looking at the scope of studies and research on this topic, cannabis can be seen as an adjunctive treatment to aid in glaucoma patients, but not the first choice for treatment. Plenty of effective current therapies are available for glaucoma patients and due to the serious nature of this disease, expert and careful medical care is required. Maybe one day cannabinoid eye drops can be used and designed to treat this disease with direct absorption through your eye and no systemic side effects. Also, if you have glaucoma and you currently use cannabis you can rest assured that the use of cannabis will not hurt your condition, and may aid in treating it. Currently, it has not been researched whether cannabis can have a protective effect against the development of this disease, but it certainly seems possible.
While this condition certainly belongs on the list for medical cannabis, it should only be used in addition to regular ophthalmologic care and therapy. New therapies and future treatments with extracted or modified cannabinoids may better incorporate cannabis into glaucoma treatment but stick with your specialist’s recommended therapy using current drops, drugs, or medications.
Dr. Stanley R. Manstof
MMCC Certified Provider
Member Americans for Safe Access
International Cannabinoid Research Society
Certified Patient Caregiver
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