A person who is blind has lost his or her sight. When this word is used literally, a person really can’t see:
Tony has been blind since he was a little boy.
He was blinded in a tragic accident. (The sentence uses the word "blind" as a verb.)
Blind people can read by using braille.
People who are blind often use guide dogs.
He uses a guide dog.
The word "blind" can also be used figuratively. In this case, a person has the physical ability to see but fails to understand a situation or doesn’t realize that something is true:
Blinded by ambition, she neglected the responsibilities of raising her two children.
Bob was blinded by Griselda’s beauty and could not see the dark side of her personality.
Maria is blind to the possibilities offered by a good college education.
Sometimes we say we are blind because a condition creates difficulty for clear sight:
She was temporarily blinded by the snow and the sunlight.
This car has a blind spot. It’s hard to see things on the left side.
The driver was blinded by an oncoming car that had its brights on. (brights = bright lights)
The word "blindness" is a noun:
Many people have some form of blindness past the age of 80.
Blindness is difficult to cure.
Ray Charles never allowed his blindness to get in the way of his interest in music.
When this word is used as a noun in the plural form, it refers to window coverings:
Blinds on the window provide privacy and control the amount of light entering a room.
Could you please close the blinds? There’s too much sun getting into the room.
At night they close the blinds. In the morning, they open them.
He uses a guide dog. 
blinds