Definition & Meaning of "(as) blind as a bat"

What is the origin of the idiom "blind as home" and when to use it?

The phrase "blind as a bat" came about due to a widespread belief that bats have weak eyesight. Although bats can see, they primarily use a special ability called echolocation, where they produce sounds that bounce back to help them navigate and locate objects in the dark. The idiom is used to describe someone with extremely poor eyesight or someone who seems visually impaired. It is often used figuratively to emphasize someone's inability to see or perceive something clearly. The phrase is not meant to be taken literally but serves as a humorous comparison to highlight someone's lack of visual acuity.