I enjoy programming and working on my game for hours straight but my eyes just cant keep up. After about 2 hours I start misreading things and I cant focus my eyes without strain. After about 8 hours I no longer can even read the screen without being a matter of inches away from it. I have never had eye problems before I started programming. I think it may be the font but when I tried making it bigger it just made it harder for me to browse large numbers of lines of code.