GW Pharmaceuticals stated the following in an article titled "Glaucoma," written by the company's Cannabinoid Research Institute and posted in the "Research & Development" section of its website (first accessed in Jan. 2004 but now available only in an archived cache of the website dated Apr. 4, 2004 via

“The ability of cannabis and THC to lower intra-ocular pressure in glaucoma was serendipitously discovered in the late 1970’s by a variety of patients and researchers. Several patients in the US Compassionate Use Investigational New Drug Program maintained their vision while employing large amounts of daily cannabis in situations where standard drug therapy failed…

An emerging concept is that glaucoma represents a progressive vascular retinopathy that requires a neuroprotectant to preserve vision. Some of the resulting optic nerve damage accrues due to NMDA hyperexcitability, an effect that THC and CBD may counter as neuroprotective antioxidants.

Thus, glaucoma is an area where cannabis and cannabinoids may offer particular advantages over available single ingredient ocular anti-hypertensive agents.”

Apr. 4, 2004