When surfing this evening, it suddenly occurred to me how I was quickly zooming in on specific areas within pages on sites I visit often. I was not even bothering to take in anything outside of these areas. Did not realize that I had developed “web vision” 
Compared notes with my wife and she too reported similar behavior. Wow! Who knew??
Pondering on the topic some more, I’ve realized that I’m likely to develop web vision for the sites I visit most frequently; unfamiliar sites cause me to pause and look around to get to what I want. There is a very interesting paradox here – online advertisers pay the most to show ads on the highest traffic sites, yet if my theory is correct, these sites are also the ones where users are most likely to completely ignore them!!
Good write up
Thanks, Dad