As for pilots' eyeballs- nothing I've read about this clearly states that anyone got close enough to get direct-eye-contact; most mentions of "visual" confirmation are talking about via cameras (and to me, the footage I've seen of it looks precisely like a camera artifact.) Also I wouldn't discount the possibility of a pilot, squinting to see a small distant object that his expensive flight equipment is insisting is there, simply hallucinating- humans are suggestible, and just as vulnerable to "sensor fusion" errors as prototype military hardware.