Researchers Link Width of Blood Vessels in Eye with IQ

According to a new study, the width of blood vessels in the retina can be a marker for brain health and mental problems.

The study was conducted by researchers from Duke University and colleagues, who hypothesized that nerves that feed the brain may co-relate with the intelligence of the person. The blood vessels could show if the person is suffering from diseases that affect cognition and memory, such as dementia.

Researchers used digital retinal imaging to look at small blood vessels in the retina, which is located at the back of the eye. These vessels share the same size and shape and resemble the blood vessels that provide nutrients to the brain.

"Digital retinal imaging is a tool that is being used today mainly by eye doctors to study diseases of the eye. But our initial findings indicate that it may be a useful investigative tool for psychological scientists who want to study the link between intelligence and health across the lifespan," said psychological scientist Idan Shalev of Duke University, and one of the study authors.

The study was conducted on people enrolled in the Dunedin Multidisciplinary Health and Development Study. There were about 1,000 people in the study and they were born between April 1972 and March 1973 in Dunedin, New Zealand.

Researchers found that people with wider retinal venules at age 38 had lower IQ than their peers. This co-relation existed even after researchers accounted for other factors such as education, health and lifestyle that may have affected the test results.

Interestingly, people who had wider retinal venules at age 38 also had a lower IQ when they were kids and teens.

It is "remarkable that venular caliber in the eye is related, however modestly, to mental test scores of individuals in their 30s, and even to IQ scores in childhood," the researchers said, according to a news release from Association for Psychological Science.

"Increasing knowledge about retinal vessels may enable scientists to develop better diagnosis and treatments to increase the levels of oxygen into the brain and by that, to prevent age-related worsening of cognitive abilities," the researchers conclude.

The study is published in the journal Psychological Science.