The human eyeball is filled with fluid which exerts pressure to keep the eyeball spherical. Glaucoma is a condition where the channels through which the fluid flows gradually become blocked, and the intraocular pressure (IOP) gradually increases causing increasing damage to the optic nerve and gradual deterioration of vision.
Glaucoma is the second-largest cause of blindness, and affects 1.5% of 50-year olds and 5% of seventy-year olds.
Standard treatments have unpleasant or dangerous side effects, and have little effect on intraocular pressures in end-stage glaucoma. Cannabis however lowers intraocular pressures dramatically, with none of the serious side effects.
Patients who find that standard medicines do not help their conditions report that smoking cannabis quickly restores their vision. Many long-term glaucoma patients have successfully maintained their sight using cannabis for 20 or 25 years, and avoided the gradual painful deterioration to blindness that is otherwise inevitable.
There are concerns about the effects on the cardio-vascular system. These disadvantages are especially significant when one takes into account that a dose of cannabis needs to be taken about every 4 hours for the full benefits to occur.
Despite the possible drawbacks, one should be reminded that using cannabis evidently does some glaucoma sufferers a lot of good. 2 out of the 8 patients who are legally permitted to use cannabis medicinally in the US have used government-supplied cannabis for over 10 years to maintain their sight. It seems cruel to prohibit and, indeed, punish the huge numbers of glaucoma sufferers that could be helped by cannabis. Following a review of existing research, the Australian National Task Force on Cannabis concluded that it would not be desirable to criminalise such users.
Ironically, the discovery that cannabis lowers intraocular pressure was made accidentally during a police experiment. They were trying to discover if cannabis caused pupil dilation in users so that they could detect and arrest them more easily!
With the 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 politicised 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.
