I wasn't sure where to post this, but biology seemed fitting for me. Sorry if I'm wrong.

I was wondering why, when we close both our eyes and look at light, it is clear we can see the light even though our eyes are closed. We can identify where the light is too.

However, when you look at the light with only one eye closed, suddenly you cannot perceive this anymore and you can only focus on the open eye's vision. It's like our brain is ignoring the closed eye's vision somehow. What is triggering this "ignore vision"? Is it the closing of the eye?

I found this intriguing and wondered how this works and/or if there is any research about it.

  • $\begingroup$ Look up "Ocular dominance" $\endgroup$
    – John
    Commented Jul 24, 2022 at 19:49

1 Answer 1


I'm only a 17 years old student but i guess this is the answer(its just what i guess, haven't seen it in any books or research): Visual pathway

This is a picture from the book Life. When both eyes are working they send signals to brain. signals from things on the left side are sent to right side of brain and signals from things on the right side are sent to left side of brain(coming from both eyes). as you can see both eyes participate in sending signals to right and left hemisphere.

On the right side of picture you can see visual cortex of right hemisphere , it has signals coming from both left and right and makes the thing we see.

While seeing through only one eye (or when you cut optic nerve from one eye) there is still signals coming to visual cortex from the other eye and that makes image of what you see.(when you close one eye there is still little signal from it if you are facing a bright light source, but signal from the other eye has more effect as its more powerful( try it by closing one of your eyes and put a torch in front of only the closed eye, if the torch is bright enough you can see bright thing there))

when you close both eyes the signals coming from both eyes are almost the same and if you face a bright thing, you almost see it.

i just guess that's the mechanism :)

  • $\begingroup$ That's a nice explanation! But there is one thing I'm confused about. So, when closing only one eye: the optic nerve is cut from the closed eye? But when closing both eyes, the optic nerve of both eyes are open? Because when both eyes are closed, you can still "see" the light. But when only one eye is closed, you cannot. $\endgroup$ Commented Feb 29, 2016 at 19:37
  • $\begingroup$ no its not cut from the closed eye, i just meant it is like cutting it, when you close the eye, the signals coming from it become weaker and less as if there is no eye. its like comparing these numbers:1-both eyes open:10000-10000 2-one eye open:10000-10(0 if the nerve is cut) 3-both closed: 10-10 10000 is soo big compared to 10 so brain somehow omits 10. $\endgroup$
    – Nemexia
    Commented Feb 29, 2016 at 19:45

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