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Take a moment and notice your nose. You can suddenly see it, but just seconds ago, you probably didn't. That's because your brain constantly filters your nose out of your vision so it doesn't distract you. Your nose is always in front of your eyes, yet your brain chooses to ignore it. If it didn't, it would block part of your view every second of the day.
This is one of the brain's many ways of helping you focus on what's important. It's amazing that your mind edits reality without you noticing.
© National Eye Institute