Visual Snow

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Visual Snow

Postby BadgerJelly on August 13th, 2017, 3:15 am 

Do you have this:

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

Visual snow, also known as visual static, is a disorder in which people see white or black dots in the whole of their visual fields.[1][2] The problem is typically always present and can last years.[3] The severity of the "snow" differs between people; in some the condition affects daily life, making it difficult to read, drive, or see in detail. The use of computer screens can exacerbate symptoms.


To add, what I experience is not "black and white", it is something more like looking close up at a TV screen, blue, green and red "snow". Also in the video embedded in the link the movement of the snow is not anything like as violent as that. I can see in right now in daylight, but most of the time I just don't pay attention to it.

At night in a darkened room it "swims" around and for the last few years I suspect its movement has something to do with how I have learned to read because the it "shifts" from left to right and I can often pick out distinct pattern (relates to link later in this post). When I was a kid I used to play a game with it and try and follow it around in the dark but as I focused the more it would swim of faster to the right of my vision and I would sit up in bed and move my head to follow it.

I can still do the very same thing I did as a child. When I focus in the dark, or rather "relax" my vision, I see a few very small "bright" yellowish white rings and when I track them as they swim across my field of vision them culminate into something like a concentric mishmash of interlaced rings. It is quite impossible to look for too long and it then quickly disappears the more I try to focus and the better I see it (which is very fleeting in any clarity due to the complexity.)

I am very curious as to what causes this and there seems to be little explanation of this. I don't find it irritating or annoying, accept sometimes when I am trying to go to sleep and get into the habit of paying attention to it and "playing the game" of trying to catch these complex circles.

Proposed diagnostic criteria for the "visual snow" syndrome:
◾Dynamic, continuous, tiny dots in the entire visual field.
◾At least one additional symptom: •Palinopsia (visual trailing and afterimages)
•Enhanced entoptic phenomena (floaters, photopsia, blue field entoptic phenomenon, self-light of the eye)
•Photophobia
•Tinnitus
•Impaired night vision

◾Symptoms are not consistent with typical migraine aura.
◾Symptoms are not attributed to another disorder (ophthalmological, drug abuse).


Then if you've ever tried meditation maybe you'll understand this better here:

https://en.m.wikipedia.org/wiki/Closed-eye_hallucination

There are five known levels of CEV (Closed-eye Visualizations) perception which can be achieved either through chemical stimuli or through meditative relaxation techniques. Level 1 and 2 are very common and often happen every day. It is still normal to experience level 3, and even level 4, but only a small percentage of the population does this without psychedelic drugs, meditation or extensive visualization training.[1]

Level 1: Visual noiseEdit



CEV noise simulation

The most basic form of CEV perception that can be immediately experienced in normal waking consciousness involves a seemingly random noise of pointillistic light/dark regions with no apparent shape or order.

This can be seen when the eyes are closed and looking at the back of the eyelids. In a bright room, a dark red can be seen, owing to a small amount of light penetrating the eyelids and taking on the color of the blood it has passed through. In a dark room, blackness can be seen or the object can be more colourful. But in either case it is not a flat unchanging redness/blackness. Instead, if actively observed for a few minutes, one becomes aware of an apparent disorganized motion, a random field of lightness/darkness that overlays the redness/blackness of closed eyelids.

For a person who tries to actively observe this closed-eye perception on a regular basis, there comes a point where if he or she looks at a flat-shaded object with his or her eyes wide open, and tries to actively look for this visual noise, he or she will become aware of it and see the random pointillistic disorganized motion as if it were a translucent overlay on top of what is actually being seen by his or her open eyes.

When seen overlaid onto the physical world, this CEV noise does not obscure physical vision at all, and in fact is hard to notice if the visual field is highly patterned, complex, or in motion. When active observation is stopped, it is not obvious or noticeable, and seemingly disappears from normal physical perception. Individuals suffering from visual snow see similar noise but experience difficulty blocking it from conscious perception.

The noise probably originates from thermal noise exciting the photoreceptor cells in the retina;[citation needed] compare Eigengrau.

Level 2: Light/dark flashesEdit

Some mental control can be exerted over these closed-eye visualizations, but it usually requires a bit of relaxation and concentration to achieve. [2][3] When properly relaxed it is possible to cause regions of intense black, bright white or even colors such as yellow, green, or pink to appear in the noise. These regions can span the entire visual field, but seem to be fleeting in nature.[4]

Level 3: Patterns, motion, and colorEdit

This level is relatively easily accessible to people who use psychedelic drugs such as LSD. However, it is also accessible to people involved in deep concentration for long periods of time. When lying down at night and closing the eyes, right before sleep the complex motion of these patterns can become directly visible without any great effort thanks to hypnagogic hallucination. The patterns themselves might resemble fractals.

Level 4: Objects and thingsEdit

This is a fairly deep state. At this level, thoughts visually manifest as objects or environments. When this level is reached, the CEV noise seems to calm down and fade away, leaving behind an intense flat ordered blackness. The visual field becomes a sort of active space. A side component of this is the ability to feel motion when the eyes are closed.[citation needed]

Opening the eyes returns one to the normal physical world, but still with the CEV object field overlaid onto it and present. In this state it is possible to see things that appear to be physical objects in the open-eye physical world, but that aren't really there.

“ If we remember that the essential difference between what we call the real world and the world of imagination and hallucination, is not the elements of which we build them up but the sequence in which these elements appear... then it follows that the sequences directed from without represent a limitation of the otherwise unlimited combinations of the selective forms released at random from within ”
— - Jurij Moskvitin, Essay on the origin of thought.[5]

Level 5: Overriding physical perceptionEdit

The internal CEV perceptions and think-it/feel-it perceptions become stronger than physical perceptions, and completely override and replace open-eye physical perceptions. This can be a potentially dangerous state if a person is still mobile while in a different perceived world, but by this time most people are motionless and not likely to do something hazardous to themselves or others.[citation needed] This is the point where most hallucinogenic references say it is a good idea to have a "sitter" present to watch over the person using the chemicals, and keep them from accidentally harming themselves or others while deep into their own world.[citation needed]

This level can be entered from complete sensory deprivation, as experienced in an isolation tank, but even there it requires great relaxation.[6][7]

According to lucid dreaming researcher Stephen LaBerge, perceptions can come from either the senses or imagination. An inhibitory system involving in the thalamus, likely involving serotonergic neurons, inhibits imaginary perceptions from becoming too activated so they turn into hallucinations. This system is inhibited during REM sleep, and the imagination can freely run into the perceptual systems. What happens at level 5 is likely that this system is inhibited, just like in REM sleep, by different causes like sensory deprivation, psychedelic drugs or meditative relaxation techniques. [8]


I mentioned this some years back and again a few times since here and there. Kind of shocked its taken me this long to actually stumble across the phenomenon online.
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Re: Visual Snow

Postby BadgerJelly on August 13th, 2017, 9:31 am 

Found another phenomenon I mentioned several months back related to this!

https://en.wikipedia.org/wiki/Blue_field_entoptic_phenomenon

The vid in the "visual snow" wiki link is not really anything like what I see but the above is almost EXACTLY what I see when I stare at a blue sky. As you can see it looks like lots of small creatures moving around your field of vision.

Turns out they actually are produced by "little living things" (I am assuming this is valid?) :


Explanation



Ophthalmogram showing blood vessels in front of the retina. Their shadow is the cause of the blue field entoptic phenomenon.
The dots are white blood cells moving in the capillaries in front of the retina of the eye.[5] Blue light (optimal wavelength: 430 nm) is absorbed by the red blood cells that fill the capillaries. The eye and brain "edit out" the shadow lines of the capillaries, partially by dark adaptation of the photoreceptors lying beneath the capillaries. The white blood cells, which are much rarer than the red ones and do not absorb blue light, create gaps in the blood column, and these gaps appear as bright dots. The gaps are elongated because a spherical white blood cell is too wide for the capillary. Red blood cells pile up behind the white blood cell, showing up like a dark tail.[6] This behavior of the blood cells in the capillaries of the retina has been observed directly in human subjects by adaptive optics scanning laser ophthalmoscopy, a real time imaging technique for examining retinal blood flow.[7] The dots will not appear at the very centre of the visual field, because there are no blood vessels there (foveal avascular zone).

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Re: Visual Snow

Postby BadgerJelly on August 13th, 2017, 10:06 am 

This guy pretty much seems like me. Not an issue for me and no idea why others want a "cure"?

Long vid (about 25 mins), more of interest to me, people who experience this or people who are interested in hearing about the weirdness of perception in general.



Another bit of info found about cause:

https://en.wikipedia.org/wiki/Lingual_gyrus

This region is believed to play an important role in vision and dreaming. Visual memory dysfunction and visuo-limbic disconnection have been shown in cases where the lingual gyrus has been damaged (due to stroke or other traumatic brain injuries). Further, impaired visual memory is related to either damage to the region or disconnections between the gyrus and other brain structures.[3] Hypermetabolism in the lingual gyrus has been associated with visual snow syndrome.[4]

Lingual gyrus activation has been linked to encoding of complex images. Subjects were scanned using fMRI while looking at pictures. The images were emotionally neutral, with no people in close-up. Subjects were tasked with memorizing the images for recognition at a later date. Data from the fMRI showed in several structures, notably the lingual gyrus. Similar activation was recorded during the recollection several weeks later.[5] It has also been shown that activation of ventral occipitotemporal cortex, including lingual gyrus, is related to the processing of visual information about parts of human faces.[6] Furthermore, left lingual gyrus activates during memorizing and maintating images of human faces in the working memory.[7][8]

Activation of lingual gyrus has been shown in selective visual attention studies. Subjects were tasked with memorizing symbols in certain visual fields while ignoring those in others. In some subjects, the lingual gyrus was activated. The hemispheric activation of the structure was dependent on which visual field the subject was focused on.[9] Hemispheric dependent gyrus activation has also been shown by isolating visual fields rather than by diverting focus.[10]
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Re: Visual Snow

Postby Braininvat on August 13th, 2017, 12:12 pm 

Have seen the blue field entoptic wrigglers, but not the visual snow unless I concentrate and then I'm aware of a very slight grainy movement when I look at flat and smooth objects or fields. What I enjoy, when I'm in a relaxed and meditative state are "eyelid movies" (that's what I've heard them called) which can be partially controlled and then fairly definite cartoon-like figures teased out of the background, which is often geometric and fractal stuff. I think there is a lot of activity in visual processing areas, like the above-mentioned lingual gyrus, that we filter out most of the time, but which can be accessed when we relax and have no external stimuli. Had never heard the term "hypermetabolism," but will probably follow up on that a bit. Fascinating thread, BJ.

I have friends in Toronto, so that fellow's accent was very familiar to me (sounds like Toronto, with maybe some UK brogue mixed in there).
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Re: Visual Snow

Postby BadgerJelly on August 13th, 2017, 12:33 pm 

I see the fuzz all the time if I pay attention to it. Are you telling me most people literally see PURE BLACK when they close their eyes???

This would really shock me! I couldn't imagine it. The blackest black I see it when I am not aware of the "visual snow" and just looking at something black. The darkest thing I see is when my eyes are open (strange as that sounds, but I've never really thought anything of it.)
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Re: Visual Snow

Postby Braininvat on August 13th, 2017, 12:56 pm 

DK, if I'm in a dark room and close my eyes, I do see more of the flickering grainy stuff, often with some amorphous forms shifting around and sometimes a whirling disk in the middle of my visual field. I can lessen it by ignoring it, but can definitely enhance it by concentrating. Especially the rotating disk or vortex effect. But, since I used to get migraines, I figure I am more prone to some overactive nerves in the visual processing area. I know a guy who gets the whirling thing and has learned to control the rotation to go either clockwise or counter.

My son is the one to talk to. He gets vivid hypnogogic imagery and can sometimes keep it going for a while, projected over his visual field with his eyes open when he fully wakes up. Not big on message boards, though, last I checked.
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Re: Visual Snow

Postby BadgerJelly on August 15th, 2017, 10:17 am 

I would really like to hear from as many people about this as possible.

Do you see it too? I am starting to think this is VERY common if not ubiquitous. Although I certainly understand that it is a real problem for some people and that those people are in the "rare condition" bracket.
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