Hi Judie: this interesting. I wonder if it is a function of concentration or a physical effect of the PD? I know when I’m distracted, I don’t always see what’s right in front of me. My significant other , who is very conscious of my issue points things out and I say “ oh, ok, I see it. “. When I drive, I tend to be more focused and I think I see all that is in front of me. But, sitting or strolling, my mind tends to relax and wander so vision/ concentration is less critical. See the doc, they should help to diagnose. Take care.