For you medical and dog people, thought this might interest you. Cerah started occasionally running into random things (like a table leg). So I looked at her eyes, she has an iris cyst and two focal cataracts that are likely causing blind spots. I e-mailed pictures to the opthalmologist who said these are likely congenital and don't progress in goldens. The cyst usually floats around the anterior chamber of the eye, then attaches somewhere, it looks attached now, and is probably why she's started acting like she has a blind spot.
Anyway, here is a picture of it I thought was kind of interesting.