Effects of Smoking Cannabis on Visual Function and Driving Performance. A Driving-Simulator Based Study

Area of Science:

• Ophthalmology
• Traffic Safety
• Neuroscience

Background:

• Cannabis is a widely used substance with limited research on its visual and driving effects.
• Understanding the impact of cannabis on visual function is crucial for assessing driving risks.

Purpose of the Study:

• To investigate the effects of cannabis smoking on visual functions.
• To evaluate the impact of cannabis on simulated driving performance.
• To determine the correlation between visual function changes and driving performance after cannabis use.

Main Methods:

• Twenty occasional cannabis users participated in a controlled study.
• Visual functions (acuity, contrast, stereoacuity) and simulated driving performance were assessed before and after cannabis smoking.
• Correlation analysis was used to link visual and driving parameters.

Main Results:

• Cannabis use significantly worsened visual acuity, contrast sensitivity, and stereoacuity.
• Driving performance deteriorated, particularly in maintaining lane position.
• Strong correlations were observed between impaired stereoacuity and driving off-center.

Conclusions:

• Cannabis consumption negatively affects critical visual functions essential for safe driving.
• Impaired vision due to cannabis use directly correlates with compromised driving performance.
• Public awareness campaigns are vital to deter driving under the influence of cannabis.