MARIHUANA SMOKING AND INTRAOCULAR PRESSURE

Journal of the American Medical Association, September 6, 1971, Vol. 217,
No. 10, p. 1392.

To the Editor-- It is accepted widely that the physiologic effects of
smoking marihuana are not well known, despite an acknowledged high
incidence of usage. Even the President of the United States has called for
a major effort to study drug effects in a scientific manner. In an attempt
to investigate the effects of marihuana smoking upon the human visual
system, complete ocular examinations were performed in a group of youthful
subjects, before and one hour after smoking. Selection of subjects,
medical and other safeguards utilized, and details of the protocol will be
presented in a later publication.
The purpose of this letter is to present preliminary data
concerning the most impressive change observed so far, namely, a
substantial decrease in intraocular pressure observed in a large percentage
of subjects. Applanation tonometry was performed by the same experienced
examiner, using the same tonometer for each pair of observations.
Marihuana was provided by the National Institute of Mental Health, and
assays proved the concentration of tetrahydrocannabinol to be high (0.9%).
[sic] Two grams were smoked by each subject using an ice-cooled water
pipe.
It is our hope that further investigations by clinicians and basic
scientists will be stimulated by the observations recorded in the Table.
The possible implications, including the mechanism of action, and even
possible therapeutic action in the treatment of glaucoma, are obvious.
Robert S. Hepler, MD
Ira R. Frank, MD
Los Angeles

Marihuana and Intraocular Pressure


Initial After
%
Pressure Smoking
Change

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