If you spend more than two hours staring at a screen, it's time to give it a break. Your brain cells are getting affected. Yes, if you work all day on a computer coupled with playing games on your smart phone and watching TV, then you are over exposing your brain.
Spending too much time on the screened gadgets makes the rest of the activities seem uninteresting. You lose the ability to counter unexpected situations. Spark of life goes missing. Your eyes get strained too. The only solution to counter these adverse effects is to cut down your screen time and follow the rule of 20s. Read more here.