But come to think of it, on a single day a human being usually gets to see limitless numbers of images, not all of which are necessarily in focus. Some of them look unfocused, others appear blurred, and there are also images that we only vaguely catch out of the corner of the eye. Regarding blurredness, the human eve that is continuously active throughout the day naturally can't stand still all the time, as it is certainly much too busy moving and drifting around.