CANNABIS & GLAUCOMA

With the St. Patty's Day 1999 release of the Institutes of Medicine Report on Medicinal Marijuana, the issue of therapeutic cannabis has come to the mainstream. The report did indicate that marijuana does indeed lower intraocular pressure. Unfortunately this highly politicized report took the position that "conventional" glaucoma treatments are not only superior to cannabis, but also less likely to have side effects. Indeed, the opposite is true. The fact that of the eight surviving patients grandfathered into the discontinued compassionate IND program who the federal government provides 300 joints per month to, three are glaucoma patients, demonstrates marijuana's efficacy in glaucoma treatment.

I have severe congenital glaucoma, and a number of other medical conditions. Around 1973, I smoked some cannabis before an ophthalmologist's appointment and when my intraocular pressure was tested, it was significantly lower, to the point where my doctor reduced the strength of one of my prescribed medications. I became a believer in the medicinal powers of cannabis, that day, and have used it ever since. I believe it is the only reason I can still see at all. I have lobbied for legal access to this natural medicine over the years, and the struggle continues.

The initial observation that smoked marijuana lowered intraocular pressure (IOP) in humans in acute experiments was made by Hepler and Frank in 1971. I had heard reports about this study, and in smoking recreationally soon discovered it helped relieve my symptoms. An exam by my doctor confirmed it significantly lowered my IOP.

In 1976, Hepler and Petrus reported in greater detail that 4 percent (tetrahydrocannabinol (THC)) marijuana cigarettes lowered the IOP about 27 percent more than did a placebo at 30 minutes in normal volunteers, and that 20 mg of oral THC lowered the IOP about 17 percent more than placebo at 30 minutes.

They also reported that smoked marijuana lowered IOP much more dramatically in patients with poorly controlled glaucoma, with 10 of 12 responding, and presented graphs showing the timecourse. One patient demonstrated a reduction from 40 mm Hg to 10 mm Hg in one eye and from 35 mm Hg to 15 mm Hg in the other.

Since patients with severe glaucoma did not discontinue their current therapy (pilocarpine - 4 percent, epinephrine - 2 percent, or oral acetazolamide) Hepler and Petrus concluded that smoked marijuana or oral THC were additive to the then-known classes of therapeutic agents, and presumably worked by an independent mechanism (Hepler and Petrus 1976). In these short-term studies, lasting up to 4 hours, 2 cigarettes were as effective as 20 cigarettes, and intoxication occurred.

Other studies confirmed that the marijuana could have a significant adjunctive effect in glaucoma patients, with Cuendet and colleagues reporting that 12/16 eyes of 10 patients had a reduction of 15 percent or more (Cuendet et al. 1976).

As a long term medicinal cannabis user, I believe that since cannabis is known to have significant neuro-protective properties, it not only lowers the IOP, but also protects the optic nerve from damage. I feel this mechanism is what has preserved my eyesight, and that of other long time users such as the three glaucoma patients receiving marijuana from the federal government's IND program. Since federal authorities have announced new regulations that allow private researchers easier access to government marijuana supplies, this would make an excellent research project. A good start would be to compare a population of long-time cannabis users against a group who have used conventional medications. I have no doubt that those patients who employed cannabis would have less damage.