Cannabis and Glaucoma: How Does it Work?
When we talk about glaucoma, we refer to a series of processes that cause optic neuropathy; its evolution is chronic and is one of the leading causes of blindness worldwide.
It affects more than 57 million people and can be associated with the following risk factors: people over 40 years old, diabetes, myopia or hyperopia, and hereditary factors.
The primary occurrence in the development of glaucoma is an increase in intraocular pressure.
In the eye, there is constant drainage of aqueous humor (the fluid nourishing avascular structures such as the cornea and lens). Suppose this drainage decreases or is inadequate, either due to a physical obstruction (closed-angle glaucoma) or an alteration of this system (open-angle glaucoma). In that case, the aqueous humor accumulates in the anterior chamber, increasing the pressure inside the eye.
Consequently, blood flow to the retina (the sensory organ in charge of vision) decreases, leading to a degeneration of the optic nerve, resulting in various symptoms: decreased visual acuity, eye pain, colored halos, headache, nausea, and vomiting.
However, several research studies have revealed that inhaled cannabis decreases intraocular pressure in open-angle glaucoma compared to placebo groups.
The mechanism by which cannabis exerts this effect may involve CB1 cannabinoid receptors in locations related to the production and drainage of aqueous humor that causes a hypotensive effect in the eye.
Lowering the pressure inside the eye improves arterial flow to the optic structures and decreases tissue damage; this is how cannabis works on glaucoma.
CB1 and CB2 receptors, linked to neuroprotective activity, increase survival and inhibit excitotoxicity on retinal ganglion cells. They contribute to the therapeutic effect of the plant in this pathology.
It is vital to note that the use of cannabis to treat glaucoma must be prescribed and monitored by a medical specialist.
Effect of Marihuana on Intraocular and Blood Pressure in Glaucoma [https://doi.org/10.1016/s0161-6420(80)35258-5]