Blindness is the inability to see, either completely or to a degree that makes normal sight impossible. A person who is blind might see nothing at all, or might see only blurred shapes and light. Some people are born blind, while others lose their sight later in life due to injury or disease.

People who are blind develop remarkable abilities with their other senses. They might read using Braille, a system of raised dots that form letters and words you feel with your fingertips. Many use white canes to detect obstacles while walking, or work with trained guide dogs who help them navigate safely. Modern technology also helps: screen readers can speak aloud what's on a computer or phone.

The word also describes refusing to see or acknowledge something that's right in front of you. When someone has a blind spot, they can't or won't see a particular problem. You might say a friend is blind to their own talents if they never notice what they're good at. Sometimes we talk about blind loyalty, meaning devotion so strong that a person ignores obvious problems. A judge wears a blindfold in symbolic images to show that justice should be blind to wealth, power, or appearance, treating everyone equally regardless of who they are.

Throughout history, many blind people have achieved extraordinary things: composing music, teaching, writing, inventing, and leading others.