Every so often somebody asks me about marijuana. No, they don’t want to sell me some weed, rather, they want to know if I can prescribe them some!
The practice of ophthalmology and controlled substances go way back. Did you know that the first legitimate medical use of cocaine occurred in 1885? Cocaine drops were administered for local anesthesia during eye surgery. Eye specialists also used topical cocaine eyedrops to establish (or refute) the diagnosis of Horner’s Syndrome – an interruption of sympathetic nerve fibers to the eye.
Many glaucoma medications work by reducing the production of eye fluid (aqueous) and/or accelerating its drainage from the eye. For over a decade researchers have known that the active ingredient in marijuana (tetrahydrocannabinol-THC) can lead to a pressure reduction in the eye.
So, dude, should all glaucoma patients start lightin’ up?
Scientists want to create chemical analogs, drugs that simulate THC’s chemical activity without the psychoactive high. Best data to date shows that THC will reduce the intraocular pressure, but not as much (nor as consistently) as other proven medications. Volunteer patients using topical THC eyedrops do not get high, horny, or hungry.
There already exist many more consistently effective eyedrops that are proven to lower pressure and reduce the risk of glaucoma damage. Given that doctors want to offer their patients the best treatment, there is no moral justification to prescribe an inferior drug.