“We blink up to two-thirds less often per minute when looking at a screen, which can dry out our eyes, causing irritation. To help maintain a healthy level of moisture and reduce eyestrain, get in the habit of looking at something at least 20 feet away for at least 20 seconds every 20 minutes.” 

--Mark Rosenfield, PhD, professor of clinical education at the State University of New York College of Optometry