How come when you close both eyes you see black but when you close one eye you just see nothing?

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Why don’t you see black on that one eye when you close it?

In: Biology

Because you brain is constantly editing what you see to make sense to you. Having half your vision black would be confusing, so it prevents you “seeing” the other half.

Your brain is a very sophisticated computer. You’ll notice you actually can see red through your closed eyelids, if you look at the lights.

What happens is your brain filters out the one eye that’s seeing all red as unnecessary information and only utilizes the eye that can see a full picture.

Try closing one eye and holding your hand over the other, but far enough that you can see light leaking around the edges. You’ll notice the eye you closed is actually “visible” now as a reddish blob.

Our brains are really good at filtering out constant signals like the hum of machines or say the tick-tock of a clock. We only notice changes to our environment, and with a closed eye there is no change to notice. It’s kinda like how your nose is in your field of vision but you don’t notice it 99.9% of the time.

The same way it’s hard to see the rest of the sky when you stare at the sun.

You can see the black with one eye shut, but because there’s light entering your open eye it grabs most of your attention and focus. You can see the black of the closed eye if you try.

I do see black in that eye – what are you all on about??

Have you noticed you don’t see your nose either?

Yo I just closed one eye to see what OP was talking about and I’m freaking out. I never realized that

Another part of this is due to overlapping fields of view. Consider this: open just your left eye; then close it and open just your right eye; then alternate back and forth. While there’s a little difference, you’re seeing mostly the same stuff, right? Each eye, with the exception of what’s on the periphery, sees almost all of the same scene content as the other (i.e. they have largely overlapping fields of view). With one eye open, we still see something like 95% of what we see when both eyes are open. With both eyes closed, our field of view is 100% reduced; however, with only one eye closed, our field of view is only marginally reduced. Therefore it makes sense that we wouldn’t notice the “blackness” of one eye being closed as easily as we would when both eyes are closed.