THC is a vasodialator(vaso = blood, dialate= to enlarge), it allows the veins in your eyes to relax. If you have high blood pressure you are less likely to get red eyes because it kinda balances out.
This is why glacoma is helped because glacoma causes your eyes to build in pressure and squish your optic nerve.
You’re more relaxed, and sometimes not blinking as much as your should. The itchy eye feeling from increased blood flow Can also cause eye rubbing which irritates already angry eyes.
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