Glaucoma
THC lowers eye pressure temporarily, but it wears off fast and never became a treatment — standard drops are the answer.
Other Unsupported
What the research says
The glaucoma story is a good example of why anecdotes and evidence diverge. It's true that THC lowers intraocular pressure (IOP) — it was the original 1970s discovery that launched modern cannabis research. The problem is that the effect lasts only about 3–4 hours, meaning maintaining pressure control would require being high around the clock.
That impracticality — plus the availability of effective, once-daily prescription eye drops — is why medical organizations never embraced cannabis for glaucoma. The evidence status is essentially unchanged in 50 years: a real but useless-in-practice effect.
The story repeated itself in 1984 when CBT — the trace compound called cannabicitran — was also found to lower eye pressure, this time in rabbits. Like THC, it never became a treatment; the effect was too weak and too short-lived to matter clinically.
The honest caveats
If you have glaucoma or elevated eye pressure, this is not a condition to treat with cannabis — the evidence rate is 'Unsupported' for good reason. Untreated pressure causes irreversible vision loss. Use your prescribed drops, and keep regular appointments with your eye doctor.
Compounds to explore
These are the compounds — terpenes and cannabinoids — that the research connects to this condition. They are starting points for reading a COA or choosing a product, not prescriptions. Each has its own guide with more detail.
Cannabinoid THC Lowers intraocular pressure for a few hours — but requires near-constant intoxication to maintain. Cannabinoid CBT A 1984 study found the trace compound CBT also lowered eye pressure in rabbits — like THC, it never became a treatment.