When there is so much junk on a web page that you have to choose what your eyeballs look at. It can also be used to look at the things you want on a page while trying to not look at the ads or *ahem* inappropriate content.
Can also be used to describe how it is possible to read the articles in certain magazines and not look at the photos.
As well, how you watch something you don't want to watch by choosing what your eyes look at. It is in your view but you are not looking at it.
I bought Playboy for the articles, and used my eye filters to block out all the nudity around the words.
The movie was so scary I couldn't watch but it was great.