Check out the dog, Barley, in this video: YouTube link. Notice how he doesn't seem interested in the food on the left side of his bowl. Perhaps he's blind in his left eye? But that can't be the case.
Not seeing the left (or right) side can occur with occipital or parietal lobe damage. In my last post, I mentioned how the parietal lobes help to focus attention, and that it is asymmetric. Although ...