Someone once recommended Paul McCartney's "eye yoga" YouTube video - really simple exercises that don't require windows with vertical grates or special magnetic frames.
http://www.youtube.com/watch?v=00XqvNwYMoc
PS - the most hilarious part is that the video is blurry, but the rest of my screen/browser/world is in focus, so if I do the exercises enough and suddenly his video is in focus and everything else isn't, I'm going to be pissed...
In my personal experience the various problems started to appear only after almost 20 years of staring into display. Yet once it started, there is no good way back, only trying to slow it down.