If you lost your eyes most people think it would be darkness. But I got to thinking…could you even see that? My hand or foot has no eyes, and they don’t see darkness. So if you lost your eyes what would you see? Blackness, or Nothingness?
This is just a WAG, but I’d have thought that as long as you had a visual cortex you would see blackness. After all, what difference does it make to the brain whether you have eyes or not? If nothing is travelling up the optic nerve, your eyes could be shut or you might have no eyes at all - but the brain would receive the same signal (nothing). Your hands or feet don’t send signals to the visual cortex and therefore don’t “see” anything, not even blackness.
What makes you think your brain receives no signals when you have your eyes closed? I would contend they receive signals–pictures of the backs of your eyelids.
I was always given to understand that the rods and cones of your retina only fire when light strikes them. No light = no signals (which the brain interprets as “blackness”.
That does sound plausible, and I don’t have the credentials to argue against it (nor am I sure at all you’re wrong anyway). Strike the objection from the record until further evidence makes it relevant, then.
When I close my eyes, I don’t see blackness. Even without pressing on my eyelids, I see streaks of colour and light. When I press on my closed eyelids, the streaks become much brighter. Sometimes when I lie in bed (with nothing pressing on my eyelids) it’s so bright I think I must have forgotten to shut off the light. What could be the cause of something like this?
I apologize in advance if this is an inappropriate hijack of a thread.
I was temporarily blind, so it probably doesn’t count. I remember seeing blackness.
Just to interject some levity…my husband knew a guy who would take out his glass eye, drop it into his beer, chug it down, and then pop it out of his mouth and back into the socket. What a *lucky boy * to have witnessed that at the tender age of 10!
Yeah, but you don’t think any light waves can make it through your eyelid’s thin layer of skin?
I was always given to understand that this was caused by pressure on your retina, causing your retinal cells to fire randomly. Obligatory Wikipedia link
As for the OP, my WAG would also be that you would see darkness - no input from the optical nerve would seem to indicate darkness. I’m not sure what the difference is between seeing that and seeing nothing. Your feet don’t see anything because they have no visual apparatus whatsoever, so I don’t think it’s an appropriate comparison. If you have visual apparatus, and there’s no input, seeing nothing and seeing darkness are the same, IMHO.
Only if there’s a significant level of ambient light outside. Otherwise, no. In the pitch-dark, I see blackness whether my eyes are open or closed.
As mentioned above, it’s due to pressure on the retina. The lights are called “phosphenes”. I think you should be concerned if you see them without any pressure on your eyelids - this may mean you have excessive internal pressure inside your eyeballs. I’d go see a doctor just to make sure that you aren’t in the early stages of glaucoma or something similar.
I have a very good friend who was born without viable eyes. I asked him the same question.
“I’ve never known what light is. It’s inaccurate to say I see darkness, as I see nothing at all. My brain is not wired to see anything.”
So I’d submit that you don’t see blackness. You simply don’t see anything,
How would he know if he viewed what we would call “blackness,” though? He really can’t. That’s the thing about sighted/usighted. I believe people who lose their eyes would have the “sighted” frame of reference and would interpret complete loss of eyesight a lot different than someone who never had eyesight to begin with.
He says his brain was not wired to see anything. That could be the case. But someone who could once see but later lost his eyes would have a brain wired for vision. This thread isn’t about what blind people “see”. It’s about what people see after losing their eyes and vision.
Yeah, somebody who has gone blind will probably “see” blackness. I mean, blackness isn’t some thing, it’s just what we see when we aren’t seeing anything.
On the other hand … V.S. Ramachandran discusses something about this in his book Phantoms in the Brain. IIRC, he said that when we close our eyes, we’re still receiving visual input signals from the optic nerves and retinas; they’re just sending a baseline signal. When that signal is lost, some people experience vivid visual hallucinations instead of “blackness.”
I went temporarily blind once after falling from an… well, obstacle once. It was like being hit by a train, but when I came to my senses (with a severly broken arm, which I didn’t notice at the time) and got up and walked away, the grass went bright red, with some green spots, and then – wham! – I couldn’t see. I was terrified, because I didn’t see blackness, I didn’t see. I went down on my knees and said (my friend told me later): “I’m blind…!” After a minute or so my ability to see came back, but anyhow,
if I would describe the experience as accurate as possible, it was not like seeing blackness, it was like the sense disappeared for me, like I had no eyes, nothing. Gone. There was no seeing, there was nothing, and I find, very difficult to describe. Horrifying it was.
I have ocular migraines with scinitllating scotoma. During the migraine aura phase I lose a portion of my vision. It is not something I could ever have imagined, nor something I can describe to someone who hasn’t experienced it. It’s not black, you simply don’t see anything. There’s a hole in my vision, around which I can see but in the middle is … nothing. Not a black spot, not a hole, and to be honest it’s hard to even say how it is that I can define where the nothingness starts and stops. It’s gone within about a half hour, and my vision returns to normal.
I don’t know the mechanisms involved that cause the scotoma or whether it would be similar for someone without eyes, but I would imagine that the brain’s interpretation of no signal would not be black, but, well, nothing.
I know what you mean, XJETGIRLX. I just remembered that I sometimes get migraines like that, and it’s really weird. Sort of like my blind spot expands to a weird shape and size, but my visual cortex keeps trying to fill stuff in. It’s weird.
Ramachandran has a long discussion about this kind of thing in his Phantoms in the Brain book – about what kind of “filling in” the brain does, how good and how fast it is, etc. Fascinating stuff.
Also, Wakinyan, when you had your fall, were you hit on the back of the head? IIRC, that’s where the visual cortex is, and I’ve heard that people with destroyed visual cortexes not only go blind, but forget how to see, and all their visual memories, entirely. Sounds like that kind of thing happened to you temporarily. Must have been pretty scary!
My great-grandfather used to do something similar with his glass eye. If he needed to get up to visit the old geezer’s room he would take out his glass eye, put it next to his beer and say ‘keep an eye on this till I get back’.
This just got brought to mind—Eigengrau, the “the color seen by the eye in perfect darkness. Even in the absence of light, some action potentials are still sent along the optic nerve, causing the sensation of a uniform dark gray color.”
It was a featured article on wikipedia a few days back. Might be of some intererst.