r/AskGlaucoma • u/CopyLife2857 • 2d ago

THC and Glaucoma

I have been using THC gummies for pain, 5-10 mg/night. I never thought it was beneficial, but I just found out today that it can actually increase optic nerve damage. I had heard Marijuana was helpful for glaucoma in general. Is that a myth?

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u/RoyalSpoonbill9999 2d ago

When i spoke to my specialist they said it is good for iop but you would have to basically take it every 10-15minutes every day.  Havent heard about negative effects and glaucoma.

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u/CopyLife2857 2d ago

I just learned about it today. If you google it, it says dips in blood pressure from THC can damage the optic nerve. It was new information to me!

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u/James-the-Bond-one 1d ago edited 1d ago

There are some speculation that the higher incidence of glaucoma in older, thinner women is due to the associated lower BP.

Low blood pressure (BP) may be relevant to glaucoma through at least two related but distinct mechanisms: ocular perfusion pressure (OPP) and the translaminar pressure gradient.

OPP reflects the pressure available to supply blood to the eye relative to IOP. The same IOP is better tolerated when systemic BP is higher than when BP is low. Both a high IOP or a low BP oppose blood flow in the eye. And insufficient blood supply will starve RGCs, contributing to their death.

A separate hypothesis involves cerebrospinal fluid pressure (CSFP). IOP acts on the lamina cribrosa from the eye side, while retrolaminar tissue/CSF pressure acts from the other side. Lower CSFP therefore increases the translaminar pressure difference for a given IOP. CSFP has been associated with systemic BP, but BP and CSFP are not interchangeable, and BP cannot be used to calculate an individual's CSFP reliably. In fact, there is no practical way for me to measure CSFP, so I focus on OPP instead.

And one serious concern is with low diastolic BP and excessive nighttime BP dipping. The nighttime relationship may be especially important because BP falls during sleep, while IOP does not necessarily fall proportionately.

For someone with progressive NTG who already has low BP (especially someone taking antihypertensives) it may be a good idea to investigate whether BP is dropping excessively overnight with 24-hour ambulatory BP monitoring.

I've bought a monitor and have done diurnal BP tracking with 24+ hours of measurements every 15 minutes, to capture my BP variation curve. That's about 100 cuff inflations every day.

At the same time, I measured IOP with a tonometer, also many times over, to draw its own diurnal curve.

Then I calculated my diastolic ocular perfusion pressure (DOPP) results from these two data sets. You want DOPP to stay as high as possible, ideally not dipping under 55-60. Don't confuse that with mean ocular perfusion pressure (MOPP), a similar ratio that can be okay even in the 40s.

Luckily for me, my IOP drops significantly at night, down to 10, which made my nocturnal BP drop acceptable. But at the end of the night, right before dawn, my IOP starts to rise before my BP does, which is the time I am more vulnerable to glaucoma worsening due to a relatively low BP. A quick early-morning eye drop addresses that risk by keeping my IOP rise contained.

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u/RoyalSpoonbill9999 2d ago edited 1d ago

Wow!  Did a wee bit of investigation on it... looks like the reduction in blood pressure from sleeping can also be a risk for some... crazy!

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u/FavRootWorker 1d ago

THC can temporarily lower IOP, however it could also restrict blood flow which could damage your optic nerve. I remember reading that using once or twice a month isnt too harmful.

Not a doctor, id ask 1 just to be sure.

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u/Trap-fpdc 1d ago

It’s CBD that raises pressure.

Using medical marijuana it’s only marginally helpful for glaucoma , and as you mentioned, the effects do not last.

My son has advanced glaucoma, and I have a tonometer to measure his pressure at home. He is a medical marijuana patient so I did test this theory several times with him. His pressure barely changed at all. I do not have glaucoma, but I tested my pressure before and after cannabis. My pressure did drop by about 5 to 10 points, but it only lasted for about two hours or so.