Testing 32 Cannabinoids Revealed Some Were More Effective Than THC at Lowering Eye Pressure | Research

The takeaway

A systematic screening of 32 cannabinoids in rabbits found that certain THC derivatives were more effective than THC itself at reducing eye pressure, and non-THC cannabinoid compounds also showed activity.

Read this if you are interested in the pharmacology of cannabinoids beyond THC, particularly for potential eye pressure applications.

32 cannabinoid compounds tested for eye pressure reduction

What the researchers found

Researchers systematically tested 32 different cannabinoid compounds for their ability to reduce intraocular pressure (IOP) in rabbits. The tested compounds included derivatives and metabolites of both delta-9-THC and delta-8-THC, other natural cannabinoids, synthetic cannabinoids, and even some non-cannabinoid compounds found in the cannabis plant.

Most compounds were tested intravenously, with a few also tested topically in mineral oil. Water-soluble derivatives of delta-9-THC and delta-8-THC were synthesized specifically for topical testing in aqueous solution.

The key findings: certain THC derivatives were more active at lowering eye pressure than the parent THC compounds. Additionally, compounds other than THC and its derivatives also demonstrated IOP-lowering activity, broadening the range of potential therapeutic candidates for glaucoma.

Why it matters

This study expanded the therapeutic search beyond THC itself. By identifying non-THC cannabinoids with IOP-lowering activity, it opened the door to developing glaucoma treatments that might avoid the psychoactive side effects of THC.

The numbers in context

32 different cannabinoids tested. Included delta-9-THC and delta-8-THC derivatives, metabolites, natural cannabinoids, and synthetic compounds. Some derivatives were more active than parent compounds.

How the study worked

Screening study in rabbits testing 32 cannabinoid compounds for intraocular pressure reduction. Most compounds were administered intravenously; selected compounds were tested topically in mineral oil or as water-soluble aqueous solutions.

What this study cannot tell us

Animal study in rabbits; IOP responses may differ in humans. Most compounds were tested intravenously, which does not reflect a practical route of administration for glaucoma patients. Topical testing was limited to a few compounds.

How to read the evidence

An animal screening study providing pharmacological data across many compounds. Valuable for identifying candidates but not directly applicable to human treatment.

When this study was published

Published in 1984. Modern glaucoma treatment relies on prostaglandin analogs and other drug classes rather than cannabinoids.

The bigger picture

While cannabis-based glaucoma treatments never became mainstream (IOP-lowering drugs like prostaglandin analogs proved more practical), this study was important for establishing that the cannabis plant contains multiple compounds with potential therapeutic activity beyond THC alone, a concept central to modern cannabinoid medicine.

Questions still open

Which specific cannabinoid derivatives showed superior IOP-lowering activity? Can these be formulated for practical topical delivery in humans? Do the non-THC active compounds also produce psychoactive effects?

Common questions

Were any compounds better than THC?

Yes. Certain derivatives of both delta-9-THC and delta-8-THC were more active at lowering eye pressure than the parent THC compounds.

Did only THC-related compounds work?

No. The study also found that compounds other than THC and its derivatives had IOP-lowering activity, including some non-cannabinoid compounds found in cannabis.

Read the original research

Cannabinoids in glaucoma II: the effect of different cannabinoids on intraocular pressure of the rabbit.

Current eye research, 3(6), 841-50

View on PubMed ↗

Citation

ElSohly, M A; Harland, E C; Benigni, D A; Waller, C W. (1984). Cannabinoids in glaucoma II: the effect of different cannabinoids on intraocular pressure of the rabbit.. Current eye research, 3(6), 841-50.