believe one's eyes
to believe what one is seeing
We could not believe our eyes when we saw the three bears on the highway.

[TahlilGaran] English Idioms Dictionary ▲

believe one's eyes
v. phr.
1. To believe what one sees; trust one's eyesight.
■ Used with a negative or limiter or in an interrogative or conditional sentence.
Is that a plane? Can I believe my eyes?
2. To be made sure of seeing something.
She saw him there but she could hardly believe her eyes.

[TahlilGaran] English Idioms Dictionary ▲