playing long hours/eye strain

[yocrackattack]

To all you geeks who play mad long hours on the computer:
How do you cope with your eyeballs not popping out of your head? If I play for more than 4 hours I get a headache and my eyes just want to quit (I have 20/20 & perfectly healthy eyes). So when I play tournies that take a while I´m screwed. Any tips from you psychos who play 3-days straight? Would wearing sunglasses or something help? ('I´ll be back'). Let me know if there´s anything I can do.
Orale...