Does OS X have a setting that will let me apply a Gaussian Blur to the monitor or a specific window? I've seen apps like Isolator which allow one to focus or concentrate on the frontmost window by blurring out the others; I'm looking to do the opposite: blur out the main window (or the entire monitor) and be able to easily toggle it on or off.

My goal: using this with digital art software such as Photoshop or Illustrator, to create the "squint" effect one does to get a different perspective on how your artwork is progressing. I'd like to be able to toggle this on so I can work in "squint" mode for a bit, then toggle it off. Would be great to be able to easily set the blur level as well.

Hoping it can be accessed and toggled via Core Image and AppleScript or similar.
Warning: this is a workaround.

Terminal.app lets you set the exact settings of its window. If you set them correctly, you can get a transparent window with a gaussian blur. If you simply leave a window open in the background in Terminal while doing your work, then bring up Terminal when you want to, this should work great. You can even make the text transparent if you want.