Can anyone make any recommendations for Mac apps that enable you to blank the screen except for a selected area or window? I would like to have this functionality for my iMac. There are a few apps within the PC world that effectively do this, such as Zorro and TunnelVision, but so far, I haven't found anything similar for Mac. Essentially, in a text-heavy document (such as an essay or article), I need to be able to blank all surrounding text with the exception of a selected area that I can move as I read through the document. This would be somewhat similar to the Loupe tool in Acrobat, but ideally, I would like to have an app that accomplishes this with any text via hotkey activation. Thanks in advance for any help!