Computer Vision - How do you correct this?

I do not have the luxury of taking 10 minute breaks nor can I do eye exercises when I am in cl. I stare at the computer screen for 4 hours straight and I start to get blurry vision in my right eye only that sometimes lasts for 2 hours afterwards- especially in fluorescent lighting. What is there to help me when I normally have 20/20 vision? I'm desperate as this has made me concentrate less in cl from the distraction.