Regarding Adventure Time, there is a character called Jake the dog. It's always bugged me not knowing why his eyes are white where the pupil should be, and black where the iris should be (i.e. inverted).
I used to think he was wearing some really thick monocles in both eyes, but they do seem to "twinkle" every now and then (but given how weird adventure time is, I wouldn't be surprised if these monocles could twinkle like normal eyes - assuming they are monocles):