Eyesight is your ability to see. When you have good eyesight, you can read signs from far away, spot details in pictures, and watch a bird soar across the sky. When someone's eyesight is poor, things look blurry or unclear, which is why many people wear glasses or contact lenses to help them see better.

Your eyesight depends on how well your eyes work together with your brain. Light enters through the lens of your eye, creating an image on the retina at the back of your eyeball. Your brain then interprets these signals into the images you see. Some people are born with very sharp eyesight, while others develop vision problems as they grow. Many people's eyesight changes over time: you might need glasses as a child, or your vision might weaken as you get older.

The word appears in many common phrases. When something happens before your very eyes, it means you watched it occur directly. When someone is within eyesight, they're close enough for you to see them. People also sometimes use eyesight more broadly to mean perception or judgment, as when they say “in my sight” to mean “from my point of view,” though this usage is less common today.