Cannabis is a long-utilized treatment for glaucoma and has recently been linked to an improvement in eyesight over time. When you smoke weed, THC instantly lowers blood pressure which leads to dilated blood vessels and increased blood flow throughout the body. The blood vessels in the eye also expand, which causes the bloodshot eye effect. Given that one of the telltale signs of pot smoking is bloodshot eyes, some people are curious to know whether regular cannabis use could have damaging impacts on the eyes.
Cannabis and your eyes
While there are instantaneous, visible impacts on the eyes after you smoke, there seem to be no long-term impacts to be concerned about. In fact, there are only two temporary effects that researchers have pointed out.
1. Peripheral vision is lowered after smoking
This is what some anti-marijuana agencies point to when speaking of the dangers of driving high. Many high drivers overcompensate for this unknowingly by checking their blind spots and mirrors more than usual to ensure safe turns, safe lane changes, and avoid accidents. But again, this issue is largely confined to the 1-2 hours one spends high.
2. Slower information processing
Earlier in 2017, Jama Opthalmology, a medical journal published by the American Medical Association (AMA) determined that regular cannabis use could lead to a delay in retinal information processing. But in spite of how scary that sounds, the study’s lead author Dr. Vincent Laprevote had this to say,
Such an anomaly could be imperceptible for cannabis users. However, it is important, since it could reflect the changes in the communication between neural cells implied by regular cannabis use.
To summarize, any changes in retinal function are incredibly minuscule. Additionally, there are many larger threats to our retinas that exist in everyday life. Laser pointers at check stands, vitamin deficiencies and looking directly into the sun are all more harmful to the eyes than smoking weed.
What about broken blood vessels?
There is also some speculation regarding broken blood vessels (subconjunctival hemorrhages) in the eye due to smoking cannabis. Since cannabis actually lowers eye pressure and dilates these vessels, it is highly unlikely that smoking it would cause broken blood vessels.
However, strong coughing and sneezing can definitely cause such a hemorrhage, and we all know that strong fits of coughing are a common result of smoking pot. So, if you wish to avoid additional stress on the eyes due to coughing, take smaller hits.
Also, if you’re already suffering from a broken blood vessel in the eye, smoking can cause further dilation of those vessels and delay healing. Even though subconjunctival hemorrhages are harmless and tend to disappear within 2-3 weeks, it’s a good idea to refrain from smoking until the eye is fully healed.