Can looking at a screen for too long affect a humans eyesight?

Question: Can looking at a screen for too long affect a humans eyesight?
- Keywords:
  eyesight,
  human,
  screen
Asked by SectumSarzzies to Dervil, Saoirse, Stephen on 18 Nov 2016.
- Stephen Davitt answered on 18 Nov 2016:
  
  Yes, or at least all the signs point to yes, looking at screens we usually spend long extended periods, this can cause eye strain, itchy eyes, headaches, and even blurry vision