Cormac McCarthy does that; just when you round a bend you see a tree that looks a little odd…
What Saramago does however is to get the reader riled up on his own and then calm him down. I have found that some of the things that have me making faces in disbelief–like after the previous posting's scenario and when the doctor's wife is so damned understanding she helps her husband back to his own bed–are dealt with in a finer depth a page or two later.
In this instance, as the doctor's wife gently consoles the girl with dark glasses and shares her secret of her vision, there is an empathy between the women and yet I wonder if on some dark level in the doctor's wife she isn't saying "Ha! I watched the whole thing, bitch!"
I think Saramago likes to play with human nature and push people to a point where not only his characters but the readers go through some mental adjustments.