Cannabis remains problematic for glaucoma
Anecdotal reports of long-term use for glaucoma have varied. They include both dramatic IOP reduction with good functional status on one hand, and progression to blindness on the other.
Summarizing the evidence, led the National Academies of Sciences, Engineering, and Medicine concluded this year that “there is limited evidence that cannabis or cannabinoids are ineffective for improving IOP associated with glaucoma.”
Physicians should educate patients wanting to try cannabis for glaucoma about its limitations, Dr. Radhakrishnan said.
Side effects may include addiction, structural brain changes, decreased intelligence quotient (IQ), impaired cognitive function, development of psychotic disorders, chronic obstructive pulmonary disease, and increased risk of motor vehicle accidents.
“For obvious reasons, we don’t advocate smoking,” she said.
There is no uniform standard for production, so products and potencies vary.
It’s hard to control the dosages when smoking marijuana. With oral consumption gastrointestinal absorption varies.
There are fewer respiratory symptoms with inhaled vapor, but much remains unknown about the volatile toxins with this route of administration.
While topical application may seem best suited to treating eye diseases, cannabinoids are highly lipophilic and this approach hasn’t worked in studies so far.
“Nowadays, we have much better eye drops,” Dr. Radhakrishnan said. “You must remember that in patients using latanoprost or timolol the potential for addiction is zero.”
These drawbacks “preclude recommending this drug in any form for the treatment of glaucoma at the present time,” according to a 2009 position statement by the American Glaucoma Society. A Task Force on Complementary Therapies of the American Academy of Ophthalmology reached similar conclusions in 2014.