I use this method to compare two images or pieces of text, but instead of relaxing the view, I do it cross-eyed, because this removes the requirement that items from both documents can only be separated at max by the separation width of the eyes.

So for example today I was cleaning up a server, freeing up some space, and then made it send me a storage space summary. I compared that one with the one I always get sent at midnight, put them side by side, and compared them via the cross-eye method. Small differences are always noticeable.

I also consider it as my cheat in order to solve those puzzles where you have to find the differences between two images, it doesn't get any easier than this.