All those screens and devices are adding up to hours and hours of focused eye use. Does it have consequences?

Americans now spend an average of 10.5 hours per day on screens and/or devices. All those hours can add up to eye fatigue, lost sleep and other related issues for some people. My story for the Health section of the San Diego Union-Tribune: http://www.sandiegouniontribune.com/lifestyle/sd-he-screen-time-20161219-story.html