Glaucoma is a well-known eye disorder characterised by abnormally high pressure within the eyeball that leads to loss of retinal ganglion cells in a characteristic pattern of optic neuropathy. Although raised intraocular pressure is a significant risk factor for developing glaucoma, there is no set threshold for intraocular pressure that causes glaucoma. Nerve damage may occur at a relatively low pressure in some patients, while others may have high eye pressure for years and yet never develop damage. Glaucoma affects one in two hundred people aged fifty and younger, and one in ten over the age of eighty.
If not treated, however, glaucoma leads to permanent damage of the optic nerve and resultant visual field loss, causing impaired vision and sometimes blindness. The loss of visual field often occurs gradually over a long time and may only be recognized when it is already quite advanced.
Several drugs with different mechanisms of action are currently available for the treatment of glaucoma, each with a specific mechanism of action and efficacy or tolerability. New molecules and mechanisms of action are the subject of much research. Cannabis, or marijuana, is known to reduce the intraocular pressure. However, the widespread use of cannabis as an illegal recreational substance as well as its side effects have limited its application for treating the intraocular pressure in glaucoma.