Have your vet check his eyes, and if he sees anything, he'll probably refer you to a vet opthalmologist. The same thing was happening with Shaye. We took her to the specialist and he found she has astigmatism right in the center of her right eye. When she is just sitting around not doing anything else, she sees that dead spot in the middle of her eye and keeps trying to catch things that are not there as well. We were afraid it was a cataract, but it is not, and should stay the way it is forever - nothing to be done about it, but maybe she will get accustomed to ignoring it after a while. We wondered about the problem being seizures as well, but that was not the problem. Do have it checked out thoroughly.