Glaucoma is a group of eye diseases that cause damage to the optic nerve. The optic nerve is the part of the eye that delivers images we see to the brain. Glaucoma is often refereed to as the silent thief of sight, gradually stealing without warning and often without symptoms. If left untreated, glaucoma can lead to blindness.   It is among the leading causes of blindness, affecting more than 60 million individuals worldwide.

It was once thought that elevated pressure inside the eye was the main cause of optic nerve damage. Although elevated pressure is clearly a risk factor, we now know that other factors must also be involved because even people with “normal” pressure can experience vision loss from glaucoma.

The primary benefit that medical marijuana provides for glaucoma patients, is its effect on intraocular pressure (IOP). In one study, more than 75% of patients who smoked marijuana using an ice-cooled water pipe experienced a reduction in IOP of 16-45%. Another study used cannabinoids contained in medicinal marijuana, and found a significant drop in IOP in patients who took THC and cannabidiol. A third clinical trial also found that medical marijuana reduces intraocular pressure, as well as blood pressure overall.