A lot of people associate smoking cannabis with overly red eyes, and you may be surprised to learn that the main reason for this effect has little to do with the smoke itself. In fact, red eyes from cannabis use can actually be a strong indicator of increased health and vitality. Here’s why.
Reasons for the Redness
For in the majority of people, it’s the THC found in cannabis and not the smoke itself that creates the red-eye effect. This is because THC binds with a receptor in your body called CB1, and there are an abundance of these type of receptors in the human eye. This binding action activates signals to lower blood pressure throughout your body, including the ‘intraocular’ pressure in your eyes. When intraocular blood pressure is lowered, your vessels open up wider, and this causes more blood to rush into your eyes.
There are also some people who are allergic to smoke, or irritated by it, and would therefore experience some kind of eye redness regardless of the type of smoke they are exposed to. A third less common reason for eye redness is an allergy to cannabis itself.
THC’s ability to lower intraocular blood pressure is actually a very positive benefit for people who are suffering from the eye disease glaucoma, a condition that affects more than 400,000 Canadians. The high pressure associated with this condition leads to optic nerve damage and eventually blindness. Cannabis therapy administered via edibles can lower this pressure for up to eight hours, which helps to slow down glaucoma’s progression.
