The eyes are the window into the soul — and also into judging children’s risk for future cardiovascular disease. A recent study has found that the more time children spend in front of a screen, the more likely they’ll have narrower arteries attached to the back of their eyes, which is an indicator of cardiovascular disease in adults. According to figures from the U.S. Centers for Disease Control and Prevention, the average family home has four televisions sets and 64 percent of children have TVs in their own room. Additionally, children also regularly spend time in front of computers and video game consoles.
How much time do children spend sitting in front of screens? On average about 5.5 hours per day.
That much sitting around can be bad for anyone’s health, said Bamini Gopinath, a medical doctor at the University of Sydney in Australia and the study’s lead author, but it’s especially harmful for children. Loafing around in front of the tube also tends to lead to eating junk food, making the activity doubly dangerous.
Previous research has found that spending significant time watching television can lead to serious weight problems in children — which can predispose them to serious health complications later in life, including heart disease and diabetes.
But researchers had so far found little that points to specific, risk-indicative body changes in children that occur due to a sedentary lifestyle.
Gopinath and colleagues looked at one well-known element of cardiovascular disease risk in adults: a narrowing of retinal arteries.
The researchers collected data from parents on the physical activities and TV-watching habits of 1,492 6- and 7-year-olds living in Sydney. Next, the scientists photographed the children’s eyes with a special camera that allows doctors to see behind the eyeball.
They measured the diameters of the children’s retinal arteries and compared those data to the parents’ responses. Gopinath found that children who spent the most time watching TV, in front of the computer and playing video games had retinal arteries that were on average 2.3 microns (a micron is about one thousandth of a millimeter) narrower than their more active peers. The researchers published their results this week in the journal Arteriosclerosis, Thrombosis and Vascular Biology.
That may seem like a small difference, but it’s almost exactly the same effect you see in adults who are at risk for cardiovascular disease, Gopinath said.
While it’s hard to tell whether such narrowing compromises the children’s current health, he added that such changes are usually indicative of other risks.
“Looking at the changes in the artery… will give you a pretty good idea of what’s going on in the rest of the body, particular in the heart,” Gopinath said, “And it is quite representative of changes going on in the other vessels throughout the body.”
He said these effects are probably reversible if children change their behavior and engage in more physical activity and less sedentary routines.
How much TV is OK? Gopinath recommends no more than two hours for children.
Patrick McBride, a cardiovascular health researcher at the University of Wisconsin – Madison, said the study extends what children’s health researchers already know about the link between TV-watching and childhood obesity.
“It’s really nice to have this kind of quantifiable data that points to what we’ve been saying for a long time,” he said.
