Glaucoma is a term describing a group of ocular (eye) disorders resulting in optic nerve damage or loss to the field of vision, in many patients caused by a clinically characterized pressure build up in regards to the fluid of the eye (intraocular pressure-associated optic neuropathy).

In a large number of glaucoma patients, however, the intraocular pressure (IOP) is normal, i.e. below 20 mm Hg. These patients display the same signs of glaucomatous damage as those with an elevated IOP; their condition is thus called normal tension glaucoma. The disorders can be roughly divided into two main categories, “open-angle” and “closed-angle” (or “angle closure”) glaucoma. The angle refers to the area between the iris and cornea, through which fluid must flow to escape via the trabecular meshwork, an area of tissue in the eye located around the base of the cornea. Closed-angle glaucoma can appear suddenly and is often painful; visual loss can progress quickly, but the discomfort often leads patients to seek medical attention before permanent damage occurs. Open-angle, chronic glaucoma tends to progress at a slower rate and patients may not notice they have lost vision until the disease has progressed significantly.

Medical Marijuana Efficacy

The primary benefit for glaucoma patients is its effect on intraocular pressure (IOP).

In one study, over 80% of patients who smoked cannabis using an ice-cooled water pipe experienced a reduction in IOP of 16-45%.

A second study used cannabinoids contained in medicinal cannabis, finding a significant drop in IOP in patients who took THC and cannabidiol.

A third clinical trial also found that medical cannabis reduces intraocular pressure, as well as blood pressure overall.