See the above comment by pfooty who explains it better than I did. I don't bump into people nor bump into walls. I use my peripheral vision to see what's happening while reading my kindle.

Honestly, it's never seemed hard to me and I don't remember a time when I was not able to walk while reading without bumping into things. Even as a student when studying for exams, I'd walk around in circle in my room reading my textbooks, for some reason walking helped to better remember...