Why does vision get blurry after looking at the screen for long hours?

In this era, we can’t imagine our lives without electronic gadgets like computers, Laptops, and most importantly Mobile phones. Spending too much time on screens could be potentially harmful for the eyes. Eyes is a too delicate organ of the body and we tend to not pay so much attention to eye related issues which can eventually be sight threatening. Blurriness after prolonged screen time, often referred to as digital eye strain or computer vision syndrome, is becoming a serious issue day by day.