After rising this morning, I was eating breakfast, and then all of a sudden I saw zig-zag lines to the side of my eye(s) (I think both eyes); it lasted about five minutes, then it eased up. About 15 mins. later, it happened again. I laid down and closed my eyes, but I could still see it. It again lasted approx. 5 mins. It hasn't happened the rest of the day. Is this a concern, and should I see an eye doctor?