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Comment by adgjlsfhk1 | Hacker News Reader

I agree that it would be totally bonkers to go from 0 to humans, but I think a lot of the theory is that human brains are pretty malleable so if you manage to get an electrical signal from the eye to the brain, the brain will probably be able to do something with it (even if it's not what a "normally" connected eye would provide)

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Do we have regeneration of spinal cord tracts after injury yet? Nope—not even in rodents.

Sorry, the mammalian brain is not really malleable at this level of organization. We might get there but not by winging it with transplants in humans. Get it to work in rats or pigs and I am happily on-board.

Neural malleability is its own separate problem from lacking neural regeneration technically.

We have digital brain-spine bridges already to translate thoughts into movement via the spine via electrodes and they have done artificial spinal tissue connects in mice already. We just might have the pieces to start 'soldering' it together. Still a low chance of success. Maybe they think it might help with learning things that the mouse models cannot teach?

Imagine all you got was noise. Woof. Torture.

Most of our vision is already noise, we just make sense of it.

Even more than noise, the very center of our field of vision is blank, accounting for the retinal nerve, which the brain masks.

The fovea and the optic disk?

I thought it was a spot near but definitely not at the very center of our field of vision, and an ad-hoc experiment to try to find my blind spot seems to confirm that? (It seems to rather be in the periphery.)

Or is there another, smaller blind spot dead in the center? That wouldn't fit the retinal nerves though, would it?

EDIT: This is the one I meant: "The blind spot in humans is located about 12–15° temporally and 1.5° below the horizontal and is roughly 7.5° high and 5.5° wide." https://en.m.wikipedia.org/wiki/Blind_spot_(vision)

My understanding is the Blind spot is nowhere near the "centre" of our vision. The centre is the bit we use for visual fidelity, or central focus.

[0]"The blind spot in humans is located about 12–15° temporally and 1.5° below the horizontal and is roughly 7.5° high and 5.5° wide."

It is however quite freaky how well the brain smoothes it over so convincingly!

[0] https://en.wikipedia.org/wiki/Blind_spot_(vision)

> The centre is the bit we use for visual fidelity, or central focus.

When I got my retina imaged (routine, no problems found), I was amazed at how small that spot is when it was pointed out to me. Only a tiny part of the retina is actually seeing in high resolution. Which I guess at least partly explains why everything outside the very center of my vision seems so illegible and somewhat... "unstable" if I stare at one spot for longer.

The optic disk is not all that close to the fovea. The brain does not need to mask the blind spot when both eyes are open.

So one of the things I didn’t expect when I had a detached retina…. no darkness in that eye. The big flashing and swirling blob of light was there whether my eye was open or closed, day or night. I could look at it and identify shapes like when you look at clouds.

Many, if not I think most actually blind people don’t see blackness. I’ve read many stories about varying levels of visual ‘hallucinations’. In the absence of input the brain will come up with stuff (https://en.m.wikipedia.org/wiki/Visual_release_hallucination...).

I thought blind people don’t “see” anything at all, not even blackness. Their perception of the world is no more than what you can see out behind the back of your head. Their existence is just a bundle of senses in a void, and the occasional mental imagery.

Yeah should have been more specific there — ‘people that have lost their sight’.

Most blind people have some vision. From light, shapes, or colors. Macular degeneration limits the field of view.

I lost vision in my right eye after failed retina detachment surgery damaged the optic nerve. I don’t see blobs of light like you describe, though I do see a dim pattern of swirling lines when I walk into a dark room. Also, weirdly, if there’s a sudden noise while I’m in the dark, I often see a flash of light go off, like an old flashbulb. I’m guessing that’s my visual system somehow rewiring itself to other sensory input.

The other thing I found insanely wild was that if I looked at a repeating pattern and held still (like say a tiled floor or carpet), the image from my good eye would slowly start expanding over and filling in the big blind spot in my bad eye.

Also if lighting conditions were just right (mostly dim but bright enough to make out shapes like in the middle of the night with only some light coming through windows), my brain would ‘forget’ the other eye couldn’t see and it would look like I could see out of both eyes again. It was trippy as hell.

I have the same phenomena - loud sharp noise is like a flashbulb goes off. Reading another commenter mention EHS and looking it up, I don’t think that’s it either. Have had multiple RD surgeries myself. Hope your vision is otherwise stable!

> Also, weirdly, if there’s a sudden noise while I’m in the dark, I often see a flash of light go off, like an old flashbulb.

I get that same effect, and weirdly was just thinking about it earlier today. I don't have vision loss, but I do also get visual noise in low light. I never did find any good information about it. The closest I could find was exploding head syndrome, which I can't entirely rule out but seems highly unlikely.

There are fascinating descriptions of patient hallucinations after loss of vision in the aptly named book "Hallucinations" by Oliver Sacks.

Tons of examples, but one that many musicians with partially lost vision experienced those missing parts of their vision randomly replaced by sheet music. Stare at sheet music your whole life, and your brain starts to predict sheet music anywhere. But when they tried to play the music, it didn't make sense.

For those with complete loss of vision, the hallucinations became immersive, featuring complete scenes with people and events.

> Stare at sheet music your whole life, and your brain starts to predict sheet music anywhere.

Sounds like the Tetris effect.

https://en.m.wikipedia.org/wiki/Tetris_effect

Yes, tinnitus is an auditory version of what could happen. Probably not though.

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