Medical Marijuana: Not Useful for Glaucoma

Posted by & filed under Eye Health, Featured, Glaucoma.

 
Laura Nennig, OD

November 18, 2018

Now with the approval of medical marijuana use in Missouri, I’m anticipating many patients asking about it, some out of curiosity and others hoping to get a prescription.  Here are a few things to know.

    1. Marijuana is currently categorized as a schedule 1 drug, next to things like heroin. Regardless of where you feel it falls on the scale of potential for abuse or addition, the DEA puts it there because it lacks “accepted medical use”. That doesn’t mean it has no uses, it means the medical community hasn’t seen enough evidence to support widespread use. Using weed is not included in the standard of care doctors look to when making decisions about treatment, essentially making it ‘off label’ whenever it’s used and opening the possibly for law suits against the prescriber.
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    3. As an optometrist, I can’t prescribe it. Our license only allows us to write Rx’s for schedule 3, 4 and 5 drugs. It doesn’t matter what my stance is on the issue, it would be illegal for me to write these prescriptions. You’d need an MD (medical doctor) or DO (osteopathic doctor) to write one for you.
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    5. Marijuana is a terrible treatment for glaucoma. Although it is widely touted for lowering eye pressure, the effect lasts 3-4 hours. You’d have to wake up at night to ensure adequate control of the eye pressure. Take it from me, I regularly prescribe medications that are taken 4 times a day; patients can’t sustain that level of vigilance without the constant reminder of symptoms. Many people who we treat with antibiotics take them every 4 or 5 hours the first day or two but then start forgetting a dose here or there. Glaucoma is what’s known as a silent disease: it has no symptoms. Many of my patients do well with something that is once or twice a day, but no one would accept a recommended treatment that was dosed 6 to 8 times a day.
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    7. Even occasionally smoking marijuana doesn’t help the optic nerve (the tissue damaged from glaucoma). Marijuana reduces eye pressure but it also reduced blood pressure. One of the ways glaucoma injures the optic nerve is by low perfusion pressure, i.e. the tissue is not getting enough nutrients from the blood stream. If both the eye pressure and the blood pressure go down, the optic nerve may actually become more compromised. When I’m concerned about someone’s optic nerve health, I generally will recommend against using marijuana for this reason. Those who have robust, healthy tissue have much less to lose than those who are suspicious for glaucoma or those who have already lost vision from it.

Dr. Laura Nennig works for Eyecare Associates of Lee’s Summit near Kansas City.