BLIND BATS AT HALLOWEEN

There were number of bats in a cave.
Two bats can see out of right eye,
Three bats can see out of left eye, Four can't see out of left eye, and
Five can't see out of right eye.
What is the least number of bats in the cave & what might their eyesight have been?

7 bats minimum all can see out of only 1 eye