Research from the University of Waterloo offers surprising findings from vision tests performed on children who were exposed to recreational drugs while in the womb.

The research, published on November 19 in the journal Scientific Reports, tested higher-level visual processing, which occurs in the brain’s dorsal area and is very vulnerable to risk factors in early development, in four-year-olds who were exposed prenatally to different recreational drugs. The results showed that marijuana exposure improved global motion perception, while alcohol had a negative effect. Methamphetamine and nicotine exposure had no effect as compared with the control group.

“We were surprised with this initial finding,” said Dr. Ben Thompson of Waterloo’s School of Optometry and Vision Science. “It shows that marijuana and alcohol can have quite an impact on a fundamental aspect of the visual processing happening in our brains. But despite the apparently beneficial impact of marijuana on the development of the brain’s visual system, other research shows its use can actually impair the brain development of unborn children.”

The research was part of the IDEAL (Infant Development, Environment and Lifestyle) study, which is investigating the effects of prenatal drugs and alcohol exposure on cognitive and motor skills.

Further information: http://www.nature.com/articles/srep16921/