Marijuana and Eyes

Marijuana and Eyes 0

I had a patient come in for an exam awhile back. No, I don’t think this guy had been smoking marijuana (but you never know). He worked in a marijuana dispensary. Yep, we’ve got these little businesses all around Denver and Colorado that sell medical marijuana. And soon, there will be legal retail marijuana sales here starting January 1st, 2014. If you want to start a business selling some bud you better get here quickly!

Anyway, the patient said he sees a lot of prescriptions for marijuana used to treat glaucoma. Yeah, right. The National Institutes of Health studied the effects of eye pressure and marijuana use (tetrahydracannibinol, THC) and found that marijuana only provides a few hours of eye pressure reduction. If you want to keep your eye pressure down you have to smoke (or take the equivalent of) 6 or more joints a day. And that pretty much ruins your day I’d say.

But there’s more to marijuana and the eyes than trying to treat glaucoma (by the way, see a doctor that doesn’t sell marijuana if you have glaucoma). There’s the pupil thing. Meaning, people are suspected of being high (on THC) if their pupils are dilated. It may be because they were smoking marijuana but it’s possible it wasn’t the marijuana that made their pupils dilate. Marijuana users can have different responses and even pupil constriction. It might be something that was added to the marijuana either before they bought it or after. I’ll call it an adjuvant. But in reality, the additive might be some other drug or ingredient added for extra effect. And just to say, marijuana is also not necessarily all that organic depending on who grew it but neither are a lot of fruits and vegetables we might buy at the store.

There is an eye/ocular side-effect that is pretty common though and that’s conjunctival injection, aka, red eyes. THC is a vasodilator which means it makes blood vessels larger and that can make things redder looking in the eye. Bigger blood vessels, redder eyes. But red eyes could occur just from smoke getting into the eyes or a lot of other things (maybe one of those adjuvants). The over-the-counter drops for getting the red out are called vasoconstrictors. The chemicals in those eye drops constrict blood vessels and make them smaller. Thus, a marijuana user might also be a “get the red out” Visine user (or similar product).

You guys stay tuned to what happens starting next year in Colorado. This will be interesting.


marijuana states

marijuana states



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Is it eye pressure?

Is it eye pressure? 0


Why did I just say no? Because the eye is full of fluid. It’s very very difficult and unlikely to have excess fluid pressure that you can feel in your eye which means it’s very very unlikely there’s more fluid in the eye. If that were to ever occur your vision would also be affected. But let me explain what changes can happen around the eye to make you feel “eye pressure.”

First, your body and the effects of anything on your body can’t compress or expand fluid. It’s just not going to happen. But air can be compressed or decompressed (there’s no air in the eye). So we need to figure out where that air is and it’s usually behind the eyes in the sinuses. I’m not going to talk about the pressure you might feel in your ears but that also has to do with compressing or decompressing air as well.

So why do the sinuses have air and how does that occasionally cause this referred pain issue when you say you have “eye pressure?” There are many reasons why air is there and I’ll leave it to the article below to explain that. Inside the sinuses (and the frontal sinus right behind the eyes) there is also mucous tissue. I’m sure everyone reading this is aware of the word sinus and has probably seen ads or commercials on tv advertising some medication for colds and flu and sinusitis. That mucous tissue in the frontal sinus (and the other sinuses) will secrete mucus to try and clear out debris and can overreact in such a way as to block the air flow through the sinus which then affects (in the case of the frontal sinus) the supraorbital nerve and cause the feeling of pressure. There’s got to be a nerve there to make us feel that.

Anyway, I found out that the frontal sinuses may not start to develop until one is 2 years old and aren’t fully developed until perhaps 7 or 8 years old. And about 5% of people don’t even have a frontal sinus! Maybe that’s good so they probably don’t get “eye pressure.”

But…there’s always a but isn’t there?….there’s a chance the “eye pressure” might be something in or around the eye like a corneal abrasion or that unlikely case of true eye pressure caused by too much fluid in the eye (an acute form of glaucoma), that your eye doctor would be the one to “see” for that.




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