Are you sure it's a matter of "visual confusion" and not having a lot of stuff clamoring for your attention but being blurry because it's outside the radius of your glasses? I definitely noticed things were better visually for me when I switched to contact lenses and lost the blur-circle that existed around the edges of my vision all the time.
I suspect it's not just from bad vision, because I've had problems in visually busy places even as a child, before I needed glasses. I didn't get headaches then, but I had a habit of looking at the ground all the time, which my parents taught my not to do once I got older because it looked weird. I recently tried out looking down all the time in busy places, and found it made me feel a lot calmer, and my head feel less tight. So I suspect that looking down was a way of avoiding looking at other stuff. (I decided it was too costly to use in most cases, though, because it looks really weird.)
Thanks for the suggestion, though. I guess it is possible that blur circle also contributes.
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.