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Comment by codazoda | Hacker News Reader

> Me too, and it's definitely a result of taking psychedelics. I quite like it. I suspect that I could have always made those CEVs appear, but I didn't "know how" until taking psychedelics.

Me too and it's probably not a result of taking psychedelics; as I've never tried them recreationally. I did, however, have vivid hallucinations as a result of Nitrous oxide at the dentist office as a child.

I don't think I see floaters, as my vision doesn't require correction. They also seem unrelated to afterimage.

I thought these were more common, but after some research, most people only see these after applying some pressure, such as rubbing their eyes. Interesting stuff.

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If you apply pressure to your eyes, you'll see phosphenes (https://en.wikipedia.org/wiki/Phosphene).

You can also see them during meditation, and as hypnagogic hallucinations while you're falling asleep (but you might not remember this).

Hang on... so people normally DON'T see these moving colors and shapes whenever their eyes are closed?

Not all moving colors and shapes you see with eyes closes are the ones the parent describes.

There are different kinds of them... (the ones described are pressure based "phosphenes"). You describe another.

And if you close your eyes in a lit place (outside in the sun, etc), you probably don't see phosphenes at all, just various shapes and colors caused by small leakage of light through the eyelid skin).

I see them every time I close my eyes, whether in a lit place or not. The only difference is that they're always tinted red/orange/yellow, and very rarely green when I'm in a lit place (and they seem a lot more muted because they're overpowered by the outside light).

Further searching the web seems to suggest that Nitrous oxide doesn't cause hallucinations, but I remember them pretty vividly. It's also pretty well documented that we can't rely on our memories. Makes me wonder.

Mine are definitely not the same as the ones you get from rubbing your eyes. Mine happen only occasionally in a very dark room and look more like a red/orange on a black background in a kaleidoscope.

Most disassociatives like nitrous can cause hallucinations but they are more of an intense dreamlike state than what lsd causes.

With LSD hallucinations you are very much still present in the world even if you interpret things in a strange way.

With the kinds of hallucinations you have with disassociatives you may be partially conscious but you aren’t present in a meaningful way.

I have a vivid memory of a ketamine trip where I was physically in a hotel room but mentally I was flying through some alien crystalline planet. I was awake and apparently talking to people but it was definitely not the same as a psychedelic hallucination.

LSD hallucinations are more like the deep dream images where you have more or less correct sensory input, but anything that looks vaguely eye-like, for example, your brain can’t help interpreting it like an actual eye. The way your brain builds a model of reality just becomes broken and you make all these connections between things that are not normally connected.

In Denmark back in the 90s it was pretty normal to give kids (and often adults) nitrous as a sedative at dentists. I had it a dozen of times as a kid, but only once did I hallucinate anything.

I was awake and fully aware every time, but the one time my dentist voice was very boomy and reverberating and everything was black except for some animals and shapes I saw in multiple rows scrolling left and right and I remember thinking that my dentist was a big frog.

I don't know why that one time was so weird out of all the other regular ones, but I know I was still awake and I was addressed and I could reply, but I was still tripping my balls off.

N2O is culturally related to psychedelics for good reason, as it can produce/amplify those effects, so that makes sense.

The eye pressure one is a different effect though. What I'm talking about are geometric effects like gears or fractals with definite edges. The eye pressure thing is more of a blob.

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