Cannabis induces dilation and widening of the blood vessels by binding cannabinoid receptors. This increases blood flow to the eyes. Also the smoke from weed can affect the eyes thereby causing irritation that can make the eyes red.
For a person who consumed cannabis, the substance cannabinoids joined together with the cannabinoid receptors makes an effect dilatation of blood vessels. Then, it increases the blood flow in the eyeballs which causes redness.
Red eyes after smoking are related to the reason that has cannabinoid content that causes increased blood pressure and heart rate. Depending on the redness can last from 4-12 hours.
Cannabis use can cause the eyes to become red and bloodshot. This is due to the presence of tetrahydrocannabinol (THC) in cannabis, which causes the blood vessels in the eyes to widen and become more visible. Additionally, cannabis use can cause dry eyes, which can also contribute to red eyes.
Cannabinoids bind to cannabinoid receptors and induce the dilation, or widening, of the blood vessels. This increases the blood flow to these areas and causes an overall decrease in blood pressure. The increased blood flow to your eyeball causes the red appearance, and the lowered blood pressure causes the dizziness.