- Diseases, Disorders & Conditions
Visual Snow: What is this neurological disorder all about?
Visual Snow Introduction
Visual snow is a poorly understood neurological disorder that is just recently being studied as an entity of its own. People often describe it as a like a TV set without reception... that black and white static overlying across the visual field. A static that can be thin or thick, rapid moving or slow. It makes the world a little grainy and indistinct but shifting and moving at the same time. It is not unknown for people to describe heatwave effects, pulsing in the air, flickering in the visual field or other distortions within this static. Visual Snow is a visual condition often connected with persistent migraine auras but it can be seen it people who do not have migraines and in people who have migraines but experience no other aura phenomena. In fact, it does not behave like a migraine aura at all. Rather it seems like the visual filter hyperactive and not filtering out all that visual noise as it were so the individual perceives this constant moving static in their visual field. It is commonly worse in dim and dark environments but can be perceived at all times. This continuous visual disturbance consists of white and black dots, although some do have colours, in the entire visual field. A “female-to-male ratio of 1:2.2 was reported and 92% of patients had no response to medication. It appears to be a unique disease entity presenting clinically distinct from visual aura, and is often associated with other visual symptoms including floaters, palinopsia, halos, photophobia, and phosphenes. However, its onset seems to coincide with headache onset, and has a high prevalence among patients who have migraine without and with visual aura. The etiology is unknown.” (Primary headache disorders and neuroophthalmologic manifestations” Dove Press Journal Sept 13, 2012)
Most neurologists believe the condition is a migrainous phenomenon in some way which is why most people with visual snow are diagnosed with persistent migraine aura. Yet visual snow does not act like a migraine aura nor does it typically respond to regular migraine preventative treatments. In fact, recently it has been stated by Dr. Chistoph Schankin “Visual snow is almost always associated with additional visual symptoms. It, therefore, represents a unique clinical syndrome – the visual snow syndrome," he said at the annual meeting of the American Headache Society. "It is distinct from visual aura in migraine; migraine with and without aura are common comorbidities, but we don’t actually know at the moment what is the pathological link between those two conditions.”
One of the unfortunate stigmas associated with visual snow is that it is caused by illicit drug use however according to research only a small percentage of people with the syndrome have ever used drugs.
The prevalence of other visual phenomena that occurs with visual snow is “showed that in addition to visual snow, nearly all patients reported other visual symptoms, such floaters (73%); persistent visual images (63%); difficulty seeing at night (58%); tiny objects moving on the blue sky (57%); sensitivity to light (54%); trails behind moving objects (48%); bright flashes (44%); and colored swirls, clouds, or waves when their eyes were closed (41%)” (Visual snow may be a distinct clinical entity)
While visual snow is found commonly among people with migraines the fact it occurs without migraines at all is fascinating in itself for research. Likewise, when it occurs in migraine patients without aura that is a clear indication something else is going on neurologically. "'I think it’s real.' Moreover, in her opinion, the presence of visual snow alone would be sufficient for diagnosis. 'I suspect it’s migrainous because most of these people have migraines. But it’s not aura. I don’t know really what it is. It’s incredibly frustrating because nothing works. You can try every antiepileptic known to mankind, and nothing works. So I agree that this is something we need to pay attention to and help these people.'" (Visual Snow May be Distinct) It would be interesting to have a study to compare people with just visual snow and people with visual snow with migraines without aura. Migraines have a peculiar way of firing up the brain even when the migraine is not present, as in such studies that show photophobia when a migraine is not present. It would be interesting to see if there is something about having migraines, of a certain frequency or duration of having them, that makes the brain more susceptible to developing visual snow. In this case, ignoring the visual aura phenomena that might happen to be affecting the same area of the brain in patients with migraine with aura. Or maybe comparing all three. Another interesting factor research much consider are the other symptoms. Those of halos and starbursts and things one might see with people with migraines occurring... is this a hyperactivity issue or similar to a migraine aura occurring in a similar fashion? Symptoms associated with the eyes themselves are even more puzzling but if the brain isn't filtering information properly it could have a connection to increased perception of visual phenomenon that is normal but just more frequent. Either way, something is making the system go haywire and by comparing those with just the visual snow to those with migraines and visual snow it might help see what the factors are that cause this to happen. New studies on just visual snow, however, show promise in revealing more insight in what is going on with this neurological disease.
It is a fascinating problem it presents trying to sort out what is causing it, what is going on and what treatments would actually be effective. For the people suffering it they often receive little care, more indifference from neurologists than anything or a lot of treatments that do a lot of nothing. In fact, the research indicates 92% had no response to medication. It can cause a great deal of frustration, confusion, and anxiety because the condition is a constant distorting perceptual phenomenon that can affect a great deal of a person's life.
The most recent research has located the region of the visual cortex responsible for visual snow: "the relationship to migraine and typical migraine aura was recently evaluated. Further, patients with visual snow differ from controls in respect of hypermetabolism in the supplementary visual cortex (lingual gyrus). This provides evidence that visual snow, despite being purely subjective in the individual patient, has a clear biological basis. The area of hypermetabolism overlaps with the functional correlates of photophobia in migraine supporting the close relationship of migraine and visual snow." Clearly, we now know it has a biological basis and is not 'in our heads'. It can be seen. It can be located. Again, we do have a correlation between migraines and visual snow that needs to be investigated further.
Nevertheless, it remains a rare disease that can greatly impact lives. For me, personally, I have never had any medication I have responded to. I also have persistent migraine auras and was initially told visual snow was part of that. Which is why I am intrigued by the research. My own experience was that the VS came far before the auras at the young age of 12 long before my first migraine with aura. Although I may have suffered with silent migraines before I had them with the 'bang'.
Do you have visual snow...
Visual Snow image
Old migraine case studies: Descriptions and treatments
These case studies come from persistent migraine aura research which up to present has been the majority of the case studies we have seen for treatment. Now that VS is being studies on its own, with another study due to come out Spring 2014, we should know more above the syndrome as well as potential treatments for it. Old treatments as we can see from these case studies follow along with migraine treatments to treat persistent migraine auras but is vastly less successful at treating the VS.
Nevertheless you might find them interesting to read as you will recognize the patients symptoms as VS. And you will see what their neurologists went about to treat it as well as whether the treatment was successful or not.
“Three-and-a-half years prior to evaluation, the patient developed a constant “rain-like” pattern in front of both eyes, at times appearing like a carpet background, often associated with the illusion of motion. Despite atenolol, the visual patterns intensified and converted to persistent “heat waves” with flickering lights. Although extremely uncomfortable, they did not interfere with visual function. She also reported five episodes of visual “black-out” and bright “daggers and spots” lasting 40 seconds each. He complained of 8 months of “snow” and “flickering” similar to what was “between TV channels.” Initially experienced only in dark illumination, eventually the visual phenomena became constant, without headaches. SPECT scan revealed bilateral parieto-occipital hypoperfusion. An EEG was not performed. Nifedipine was unhelpful, but sertraline reduced the visual phenomena by 50%.” (The last couple of sentences there apply to migraine auras and not VS just to be clear about that. This is a good example of someone with PMA characteristics and VS symptoms).
“she saw constant white and black dots, “snow,” and “TV static” over her entire visual field that worsened when she stared at a white background. Later, persistence of visual images (palinopsia) developed.”
“They commonly described diffuse small particles, such as TV static, snow, lines of ants, dots, and rain, that lasted for months to years. Some patients reported greater awareness of the visual phenomena when looking at the sky or at a light-colored wall. Complex phenomena such as palinopsia, micropsia, and formed hallucinations were exceptional. Some characterized these unformed visual hallucinations as bothersome, uncomfortable, or emotionally disabling, but not as interfering with visual function. Other patients were unconcerned by them. For the most part, medications such as tricyclic agents, calcium channel andbeta blockers, and analgesics were unhelpful. The patients’ ages varied from 9 to 67 years;”
Persistent positive visualphenomena in migraineG.T. Liu, MD; N.J. Schatz, MD; S.L. Galetta, MD; N.J. Volpe, F. Skobieranda, MD; and G.S. Kosmorsky, DO666 NEURO1,OGY 45 April 1995
“Over the next few years, the visual phenomenon was described as “snowy vision,” which was, present all the time and would worsen episodically, unassociated with pain. The subject described the visual phenomenon as like looking at a television with bad reception. It moved and swirled, and covered his entire visual field. When he looked at the sky or a white wall, the snowy effect was dark gray. He also saw constant “sparks,”“shooting stars,” and “floaters.”
When the patient closed his eyes or looked at a dark surface, he saw the same effects, except that all of the visual phenomena were white, similar to looking at a sky full of moving and shooting stars.”495
“Since the age of 7, she rather constantly sees what she describes as television static that is getting worse and more noticeable. She sees tiny air molecules, also described as rain on a window, which are most noticeable if she is looking at the sky or a white background, present in both eyes and with the eyes closed. The symptoms can interfere with reading. “494
PMA”Medications reported as effective cyproheptadine, dihydroergotamine, divalproex sodium, (mono- and polytherapy) furosemide intravenous 20 mg once and verapamil, fusosemide intravenous 20 mg once, lamotrigine polytherapy, and nimodipine. In Dr. experience, low doses of divalproex sodium, and topiramate have been effective. In persistent visual aura was less intense on topiramate mg daily, and the palinopsia resolved. from starting treatment and complete response from several hours to 2 months and was typically weeks. Of the cases reviewed by Wang et reported headache improvement after treatment. the headache improved despite persistent symptoms, and in 2, the headache improved complete resolution of the visual symptoms. Most patients were reported as unresponsive numerous medications including aspirin, naproxen, carbamazepine, phenytoin, phenobarbital, divalproex sodium, lamotrigine, topiramate, diazepam, flunarizine, nimodipine, citicoline, verapamil, fluoxetine, sertraline, amitriptyline, nortriptyline, dothiepin, nifedipine, baclofen, propranolol, metoprolol, atenolol, sumatriptan, methylprednisolone,magnesium, acetazolamide, and pizotifen.
Migraine With Persistent Visual AuraHeadache 2012 American Headache Society (Headache 2012;52:494-501)
How would you say VS affects you
Does your visual snow..
Links to simulators
Visual snow in the News
- WNYT.com - Visual Snow: it's like having a sort of TV static in your field of vision all the
- Chloe Brookes: The woman who sees snowflakes even when it's sunny | Mail Online
The snow may be over for most of us, but for Chloe Brookes it’s a year-round nightmare. She suffers from a type of migraine doctors are still learning about.
- 'Visual Snow' Called Real, Not Drug Related
NEW ORLEANS -- A mysterious and troubling phenomenon called visual snow is a distinct syndrome that does not appear to stem from illicit drug use, nor is it a migraine aura, a researcher said here.
- Visual Snow
Eye On Vision Foundation - Floaters, Visual Snow, Macular Degeneration
- Visual Snow: Share your experiences. HELP RAISE AWARENESS. - Home
Site to promote visual snow awareness
- Visual Snow Group
Visual snow group for people with visual snow. Have a great resource of information and support.