According to a study by the University of Granada, smoking marijuana significantly changes key visual functions including visual acuity, contrast sensitivity, the ability to focus, glare sensitivity, and three-dimensional vision.
Surprisingly not many people are aware of the negative impacts that cannabis may have on vision.
Researchers from the Department of Optics of the University of Granada (UGR) were led by Carolina Ortiz Herrera and Rosario González Anera, who conducted the study which has been published in the journal Scientific Reports.
According to main author, Sonia Ortiz Peregrina, cannabis use is on the rise despite being an illegal drug.
The study, whicih was approved by the Human Research Ethics Committee of the UGR (ref. 921/CCEIH/2019) had an exhaustive visual trial that was conducted on 31 cannabis users, both when they had not consumed any substance in advance and also when they were under the effect of the drug.
Researchers also looked at the participants’ perception of the visual effects of having consumed this drug.
According to the results, following consumption, many visual aspects significantly worsened. Despite the findings, not all subjects reported a worsening of their vision after smoking cannabis. 30% reported that their vision had not suffered at all, while 65% responded that it had worsened only slightly.
