by Charles M. Lederer, MD
Published in Missouri Medicine, the journal of the Missouri State Medical Association, March/April 2012
As an ophthalmologist specializing in glaucoma, I am sometimes asked by patients whether marijuana can be used to treat glaucoma. These patients have been made curious by provocative but incomplete, and often inaccurate, media reports suggesting the benefits of this form of treatment.
Glaucoma treatment involves lowering the intraocular pressure (IOP). This helps preserve visual function by slowing or halting progressive damage to the optic nerve. Smoking or ingesting marijuana can, indeed, lower the IOP.1 In addition, THC (marinol), the major psychoactive ingredient in marijuana, has been shown to have an IOP-lowering effect when ingested orally. However, due to a variety of factors, it is not possible to transform these observations into a widespread and clinically useful method of glaucoma treatment at the present time.
The pressure-lowering effects of inhaled marijuana are variable and of short duration. To achieve continuous IOP lowering, this short duration of action requires smoking marijuana every three to four hours.2 The accompanying article describes the cognitive and systemic side effects of regular marijuana use. These side effects proscribe the continuous use of marijuana as a practical way to treat glaucoma.
There might theoretically exist a very rare patient with end-stage glaucoma in whom all methods of medical and surgical treatment have either failed or are contraindicated. Perhaps in this hypothetical isolated case smoking marijuana be considered. However, I have never advised this method of treatment, and I have never spoken with an ophthalmologist who has recommended this. Inhaled marijuana compares poorly to the eye drops we have available to lower IOP. Currently available glaucoma eye drops have been extensively studied and are usually well tolerated and effective. They have a much longer duration of action when compared to inhaled marijuana. A variety of laser and incisional surgical techniques, both established and recently developed, are also available.
Marijuana has a complex composition, containing 60 known cannabinoid compounds. Study of these compounds is ongoing, and it may well be that one or more of these compounds can be developed into a valuable medication for treatment of glaucoma. At the present, however, despite public fascination with the concept, smoking marijuana as a way to treat glaucoma is not well-established or practical, and may be a dangerous option.3
Published March 20, 2012
Charles Lederer, MD, is a fellowship-trained glaucoma specialist who has practiced ophthalmology in the Kansas City area for nearly 30 years. Selected as one of the Best Doctors in America® for eight consecutive years (2004-2012), Dr. Lederer is board certified by the American Academy of Ophthalmology (AAO) and has received an AAO Achievement Award for participation in the scientific programs of the AAO annual meeting. Dr. Lederer is also a member of the Missouri Medicine editorial board in ophthalmology.