blind as a bat

Idioms  

1. Quite blind; also, unaware. For example, Without my glasses I'm blind as a bat, or I had no idea they wanted me to take over his job; I was blind as a bat. This simile, based on the erroneous idea that the bat's erratic flight means it cannot see properly, has survived even though it is now known that bats have a sophisticated built-in sonar system. [Late 1500s]

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Example Sentences

“What we did is we used a lot of strobe lights. We wanted you to be blind as a bat when you came out of it. I wanted to screw up your vision. It was just a black tunnel, and we’d turn out all the lights and screw up your eyes. I wanted you to be all messed up.”

From Los Angeles Times

“I was blind as a bat, but I always knew where the target was,” Cooper says.

From The New Yorker

“I thought he had the ball. Blind as a bat without my glasses.”

From Literature

Samuel Johnson, one recalls, a ferociously unsociable reader, and blind as a bat, was constantly in danger of singeing his wig against his candle.

From New York Times

You’ve probably come across the phrase “blind as a bat” at some point in your life.

From The Verge