Researchers have found that marijuana use has immediate effects on the eyesight.
A study from Spain “quantified significant adverse effects on subjects’ visual systems after smoking cannabis, namely impaired contrast sensitivity and visual acuity that are especially pronounced at nighttime,” reports the American Optometric Association.
The research involved 31 subjects and was published in the journal Nature. The participants underwent visual tests and filled out a questionnaire on self-perceived visual quality.
The researchers wrote: “Cannabis is one of the most prevalent illicit drugs involved in road traffic fatalities, and its negative influence on driving skills have already been reported. Driving is highly dependent on vision, and the changes observed in this study imply a significant increase in risk.”
They also explained: “In summary, this study shows that smoking cannabis has significant adverse effects on certain visual functions, including visual acuity and contrast sensitivity, as well as in nighttime-related visual parameters, such as the (visual-disturbance index) and intraocular straylight.
“Our results could help generate a better understanding of the visual changes related to cannabis use and their implications for everyday tasks, raising awareness among users of the risks involved consuming this drug.”
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