# The Truth about Visual Snow



## Dr B (Apr 23, 2014)

Dear All

I thought I would try and provide a brief background on the phenomena of visual snow that some people here have reported experiencing and have expressed some concern about. My aim is to provide accurate information that the individual can use and I hope that knowing a little more about the condition may help alleviate some stressful feelings / thoughts. I've used a couple of papers to help compile this - plus some knowledge rattling around my brain. I intend to come back to this post, and provide some questions you can ask yourself about your visual snow experience.

Finally, although I've tried to keep things as non-technical as possible, I also don't believe in patronising anyone here. So some neurological terminology is unavoidable - however, a simple Google will help clarify. If I did this all here - it would make the discussion below far too long.

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Visual snow refers to a condition where the observer experiences excessive 'noise' in the visual system that can be akin to seeing a "television like static" superimposed on the real world. Some researchers have argued for different types of visual snow experience that may reflect different underlying mechanisms. For example, visual snow is typically transparent or achromatic, though it can also be coloured. Generally speaking it appears to reflect some form of spatial 'noise' in the visual system. Perhaps the most common type of visual snow is where the snow is relatively uniform in density over the entire visual field. It can be present in broad daylight, low-light, and even when the eyes are closed. Although the intensity of the snow can be seen to alter over time, it can also be described to be relatively constant and stable. Many patients may become more aware of it in low lighting.

Visual snow (also known as Aeropsia) is classed as a dynamic simple visual hallucination of random form, and as such cannot be classed as being similar to the other types of distortions that patients with DPD/DR experience (i.e., visual distortions or illusions). It arguably has the simplest form of all elementary hallucinations. Visual snow can be transient (particularly if it is associated with Migraine with aura) or permanent (more likely). It can be experienced across the whole field (more typical) or only part of it - like in peripheral vision (rarer).

Additional visual symptoms accompanying visual snow include; Palinopsia (persistence of a visual image after its removal from vision), Entoptic phenomena (specific stimulation), Photophobia (hypersensitivity to light), moving objects leaving trails, excessive floaters, spontaneous photopia, wriggly cell paths (visual worms), and Nyctalopia (impaired night vision). Medication is largely ineffective. Some authors have argued that visual snow can also co-occur with bi-lateral tinitus - though again, this awaits further clarification. It is now regarded that the diagnoses for visual snow is one where it is accompanied by at least 3 other symptoms. Also there is a high prevalence for patients with visual snow to have a history of migraine with aura, visual snow is a distinct clinical entity.

Visual snow is associated with drug intoxication with LSD and mescaline having been associated with its onset. It occurs with HPPD and can be a component of Migraine with aura (known as persistent aura without infarction) though it is distinct from migraine and migraine aura as well. As a consequence, the syndrome of visual snow has been argued to be real and unique. It has been noted to be associated with DPD/DR but few studies on this specific relationship have been carried out to date.

It is suspected that both central (brain) and peripheral (retina / pre-cortical) regions might play a role in the production of visual snow. There is no obvious pathology underlying the experience of visual snow. Visual snow is not a primary eye disease (i.e., the iris, vitreous fluid). However, some are now speculating that it can be linked to cell layers in the retina, or ganglion axons leaving the retina via the optic nerve. In addition, anomalies in the magnocellular portion of the laternal geniculate nuclei (LGN) & superior colliculus (SC) have also been highlighted (these structures are pre-cortical). Aberrant activity due to what is known as parasitic oscillations in certain early (ocular) cells in the visual system - which are then relayed to magnocellular portion of the LGN could be important. One possible candidate generating some excitement at the moment is the condition of, Optic neuritis - which refers to the inflammation of the optic nerve. Recent brain-imaging studies have revealed that the right lingual gyrus is more active in patients with visual snow which strongly suggests it has a neurological (cortical) basis.

Apart from all of the symptoms described above, for patients with DPD/DR there are additional second-order issues (known as secondary sequelae) that can complicate the patient experience further. The existence of visual snow can induce secondary symptoms such as anxiety about main symptoms, stress, panic attacks, depression, hyperreflexivity, and produce an aberrant salience on the symptoms and internal fears. On the downside, people who get visual snow often experience it for their lifetime. On the upside, for many it is not progressive, it gets no worse over the lifetime for most patients.

*Useful ref:*

Schankin, C.J., (2014). 'Visual snow' - a disorder distinct from persistent migraine aura. Brain, 137, 1419-1428.

Schankin, C.J., et al (2013). Clinical characterization of visual snow (positive persistent visual disturbance). The Journal of Headache and Pain, 14, p132.


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## Andre (Jun 2, 2013)

Does visual snow have anything to do with lack of focus? I thought it too abstract/subjective to understand. I feel like I dont have anymore an 'automatic focus', like it had became a manual function. There are times that a 'normal person' finds himself looking at the wall, deeply thinking about something... That's the feeling I'm talking about, but I use to feel like that in (almost) any situation.

So, I wonder if this is what visual snow is...


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## Guest (Jan 15, 2015)

Great info, thanks for putting it together.

Interestingly, when I went into three 'remission' periods from depersonalization disorder, the visual snow would leave as well. This makes me wonder if there is a psychological aspect to it for some people. I still dealt with ocular migraines w/ aura.


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## Dr B (Apr 23, 2014)

Andre said:


> Does visual snow have anything to do with lack of focus? I thought it too abstract/subjective to understand. I feel like I dont have anymore an 'automatic focus', like it had became a manual function. There are times that a 'normal person' finds himself looking at the wall, deeply thinking about something... That's the feeling I'm talking about, but I use to feel like that in (almost) any situation.
> 
> So, I wonder if this is what visual snow is...


Hi Andre

No, visual snow is not a focus issue. You might want to have an eye exam if you are having problems focusing on visual information. Visual snow will 'degrade' the visual world 'out there' to some degree but I would not describe it as a focus issue. More like, seeing through a noisy fog.


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## Dr B (Apr 23, 2014)

Selig said:


> Great info, thanks for putting it together.
> 
> Interestingly, when I went into three 'remission' periods from depersonalization disorder, the visual snow would leave as well. This makes me wonder if there is a psychological aspect to it for some people. I still dealt with ocular migraines w/ aura.


I certainly think that peoples 'awareness' of the snow varies - most certainly. Whether this is part of a wider hyperreflexivity - I dont know. Good question.


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## Dr B (Apr 23, 2014)

Bump...I thought a number of you may find this old thread interesting as many of you seem to have visual snow


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## evolvingpsyche (Oct 20, 2015)

I honestly think visual snow has much to do with focusing. I don't even think about visual snow except when something reminds me of it like this thread here.
I'm recovered but yet I have it, so it's not so black and white. I've had it as long as I can remember though.


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## flat (Jun 18, 2006)

I've had visual snow for a long time even before getting dr. Even as a kid. But it wasn't very prevalent. On bright sunny days you don't see it at all. On duller days you can see it if you look for it. It's not something that hits you in the face for me. I notice it moreso indoors than outdoors too. And you're right about the floaters. I seem to get a lot of those.


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## luctor et emergo (May 22, 2015)

> Generally speaking it appears to reflect some form of spatial 'noise' in the visual system. Perhaps the most common type of visual snow is where the snow is relatively uniform in density over the entire visual field. It can be present in broad daylight, low-light, and even when the eyes are closed. Although the intensity of the snow can be seen to alter over time, it can also be described to be relatively constant and stable. Many patients may become more aware of it in low lighting. [/font][/size]
> 
> Visual snow (also known as Aeropsia) is classed as a dynamic simple visual hallucination of random form, and as such cannot be classed as being similar to the other types of distortions that patients with DPD/DR experience (i.e., visual distortions or illusions). It arguably has the simplest form of all elementary hallucinations. Visual snow can be transient (particularly if it is associated with Migraine with aura) or permanent (more likely). It can be experienced across the whole field (more typical) or only part of it - like in peripheral vision (rarer).
> 
> [size=NaN]Additional visual symptoms accompanying visual snow include; Palinopsia (persistence of a visual image after its removal from vision), Entoptic phenomena (specific stimulation), Photophobia (hypersensitivity to light), moving objects leaving trails, excessive floaters, spontaneous photopia, wriggly cell paths (visual worms), and Nyctalopia (impaired night vision). Medication is largely ineffective. Some authors have argued that visual snow can also co-occur with bi-lateral tinitus - though again, this awaits further clarification.




Wow this is me! Thanks for posting and bumping.


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## Dr B (Apr 23, 2014)

Bump again, as many recent threads appear relevant to this. Hope its helpful


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## forestx5 (Aug 29, 2008)

And Zed would say it is all psychological and what you need is some therapy. lol. I'm thankful I don't experience visual snow, but I did "acquire" the ability to see a lot of floaters in my vision in conjunction with a lifetime of fairly frequent migraine aura. It's all related to an incident of status epilepticus/temporal lobe siezure I experienced at age 17. That's my story, and I'm sticking to it.


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## TDX (Jul 12, 2014)

It's quite disgusting that Visual Snow was *completely ignored* until people on a forum collected some money and found an interested scientist to conduct research. It is considered a rare disorder, but no epidemiological studies were carried out, so there is no definitve answer. But it wouldn't come as a suprise if it is more common than is believed. It wouldn't be the first disorder that was thought to be rare, but turned out be widespread.

Another interesting question is how many people with non-drug-induced DPD also have visual snow and how many people with non-induced visual snow have DPD. If it's higher than a control group of healthy people both of them might be somehow related. But it might be difficult to control for the influence of anxiety and depression.



> Medication is largely ineffective.


At least there is some anecdotal evidence of effective medication if it appears in the context of HPPD. But if it is idiopathic things might be different.


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## Dr B (Apr 23, 2014)

forestx5 said:


> And Zed would say it is all psychological and what you need is some therapy. lol. .....


  which is why you shouldn't listen to some people on these issues. :lol:


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## TDX (Jul 12, 2014)

The only thing Psychotherapy might do is that it helps some people cope better with visual snow, much in the same like psychotherapy for chronic pain. But in the latter the effects are not very high and many people remain severly affected, so the prospects of psychotherapy for Visual Snow may be very limited.


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## AClayP95 (Mar 31, 2015)

I had visual snow a couple years ago for about 6 months and it went away when my dp got a little better. I still have dp accompanied with some other terrible symptoms, but the visual snow is gone.

This may sound corny but it got better by me setting clear goals and having a purpose in life. I made it my mission to become a neuroscientist so I can help people like me and others, and that made me feel like I was worth something and made me more content in life in general. After I made that decision, my dp got better in the following days, and the visual snow went away...

I say that to say, the snow definitely had to do with my psychological state of mind, and may be the case for a lot of people.


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## Dr B (Apr 23, 2014)

I think attention to the symptoms plays a role, most definately (true for lots of DP symptoms I'd say). But attention alone does not fully capture their existence IMO.


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## Artmuzz (May 8, 2016)

I notice visual snow when I wake up first thing in the morning then it clears but I still notice slight visual snow when looking at something bright like the blue sky or bright white walls.


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## jestemzalamany (Sep 7, 2016)

I've had visual snow for most of my life but it got worse after weed induced dpdr. Same with floaters, blue field entoptic phenomenon, "blinking" of objects with complex pattern etc. Maybe it's due to strange brain activity in dp i dont know


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## ugh (Sep 15, 2016)

im about to go to sleep so i havent read your post but my visual snow has decreased a lot so i think its mental?

i always had "grainy" night vision before i got dpdr though...


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