In the 1970s, glaucoma became one of the first medical conditions to be cited as a justification for a compassionate exception to prevailing laws against cannabis use. Cannabis as a potential treatment for glaucoma was noted in a 1971 study, in which smoking cannabis lowered intraocular pressure (IOP) among the participants by 25 to 30 percent.81 A 1984 study in California recruited 20 ophthalmologists to study the effect of oral and inhaled cannabis on IOP levels of glaucoma patients, but only nine patients were ultimately recruited into the study. The results of this study were published in 2002 and the results were mixed, with many of the patients complaining of unacceptable levels of psychoactivity from the oral THC administered during the study. Interestingly, the two patients with the best results took smaller doses than nearly all the participants who left the study because of side effects.82