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Marijuana impacts cognition and sensory functions. The impairment is enough to create a serious hazard to driving. The rate of drivers testing positive for marijuana only in a fatal accident, has doubled in Washington and Colorado since the legalization of marijuana. Marijuana causes dysfunction in retinal processing. Marijuana inhibits up to 75% of the visual functions in the lateral geniculate nucleus, the primary brain relay nucleus. Little is known about what levels of marijuana and its primary ingredients;Cannabidiol (CBD) and Tetrahydrocannabinol (THC), impair functions enough to impact driving. Further there is no functional test available to law enforcement to support dysfunction even when the blood levels of measured THC is considered to be high enough to impair function. There is research using functional Magnetic resonance imaging that the visual system has dysfunction with acute and chronic use of marijuana.This lecture will review the available research related the visual pathway and itsrelationship to driving and cannabis use. |