not believe eyes
not believe (one's) ears
To be shocked or surprised by what one is hearing or has heard. I can't believe my ears! You're not playing with me, right? I really got the job? Jen didn't believe her ears when she heard her sister say that she was moving to Texas.
not believe (one's) eyes
To be shocked or surprised by what one is seeing or has seen. Oh, I can't believe my eyes! Are you really throwing the ball in the house right now? Did you really buy me a new car? I don't believe my eyes!
not believe one's eyes
Fig. not to believe what one is seeing; to be shocked or dumbfounded at what one is seeing. I walked into the room and I couldn't believe my eyes. All the furniture had been stolen! When Jimmy opened his birthday present, he could hardly believe his eyes. Just what he wanted!