Last week we started by looking at persistent aura without infarction. This is also known as persistent migraine aura, or PMA. This is something I have been diagnosed with, along with something called visual snow. This week, we will look at visual snow.
What is Visual Snow?
Visual snow is one of the symptoms that can go with PMA. But PMA is not the only cause of visual snow. Another common cause is having used hallucinogenic drugs like LSD, MDMA (Ecstasy) and so on. In this case the cause is called hallucinogen persisting perception disorder, or HPPD.
HPPD can be triggered by just a single dose of an hallucinogen. And there can be some time between taking the last dose and the beginning of HPPD. This is why doctors will take a drug use history if visual snow is to be diagnosed. Like PMA, the way HPPD works is not known. Another name for visual snow in HPPD is aeropsia.
A third, but rarer cause of visual snow is optic neuritis. This is inflammation of the optic nerve caused by multiple sclerosis, or MS. It is important to get the cause of visual snow checked out, therefore. Though it is much more likely to result from HPPD or PMA. Visitors on forums have, anecdotally, blamed a range of other illnesses and causes. These may include Lyme disease, auto-immune disease, long use of a VDU, dehydration and so on. But none of these claims is supported by medical evidence.
This link gives a fair demonstration of what it is like to have visual snow (which is most obvious in near or total darkness): http://www.hkj.se/vs.html
How Good is Medicine at Diagnosing Visual Snow?
Anecdotally, from a forum I have visited (like PMA in many cases too), it can be hard to get a firm diagnosis of visual snow. Many doctors still seem to be unaware of the condition. Most people’s experience is one of being referred to an optometrist, and then eventually to an ophthalmologist or other specialist before diagnosis. Others find that they are told “it’s all in your mind” (as they can for PMA).
But there are a number of researchers looking into visual snow. So if you have it, or think you do, you may find them on a forum.
Other Symptoms
There are a number of other symptoms that often go with visual snow. These include:
- Starbursts – rays that come from bright light sources,
- Palinopsia – overly long or more frequent afterimages from looking at light sources,
- Floaters – which most people can experience,
- Trails – where moving objects appear to leave a visual wake,
- Scheerer’s Phenomenon – or blue field entopic phenomenon; fast moving, wiggly white lines against a bright uniform background, which can also be common for non-visual snow sufferers,
- Halos – mist like halos around bright lights especially at night,
- Tinnitus – ringing, hissing or other noise in the ears,
- Depersonalisation-derealisation – often described as “feeling weird” or “being spaced out”.
Those with visual snow can also have what are called secondary sequelae. This means symptoms that are caused by general anxiety about the main symptoms. These include:
- Anxiety,
- Panic attacks,
- Depression.
Treatments
There is no established treatment for visual snow. PMA sufferers may have success with some of the drugs used to treat that. The two most effective for both tend to be sodium valproate and topiramate. HPPD sufferers may respond to clonazepam. Here drug abstinence is also recommended. Again, the forum I visit lists other drugs and herbal remedies that may or may not work.
I can personally say that meditation is a big help when it comes to anxiety, panic attacks or depression. This is also helpful because in meditation we learn to control mental focus. This helps work past the visual symptoms that can otherwise be overwhelming.
At the time of writing, little research is being carried out into visual snow.
Go back to Part 1 | Go on to Part 3
Sources
http://en.wikipedia.org/wiki/Depersonalisation
http://en.wikipedia.org/wiki/Blue_field_entoptic_phenomenon
http://en.wikipedia.org/wiki/Floater
http://en.wikipedia.org/wiki/Palinopsia
http://en.wikipedia.org/wiki/Visual_snow
http://thosewithvisualsnow.yuku.com
http://www.migraine-aura.org/content/e27891/e27265/e42285/e42288/e60771/index_en.html
http://www.visualsnow.com/
March 6, 2009 at 8:39 pm
Hey,
I also am a sufferer of PMA. I started getting MAs when I was 23 during my first semester of graduate school. I had five isolated instances and then didn’t experience a single migraine aura again until I was 27, when I got one out of the blue at a conference I was attending. I then moved to a different location and again, out of the blue, started experiencing a MA on average 2-3 times a week, sometimes more often and sometimes less often.
Following one of my MA episodes, I noticed a wide array of floaters in my visual field that weren’t there before. I also started getting phosphenes and just a general, weird feeling of depersonalization. The MAs persisted week after week until they subsided a little bit over the summer. Come the fall, they started up again. The floaters in my eyes have gradually increased in number.
I’ve seen an opthamologist (eyes were normal) and a neurologist (MRI came out normal). I’ve cut a lot of foods out of my diet and stick to a strict sleeping schedule now, so I get the MAs a little less frequently, but I’m still getting them a few times a month, on average.
Incidentally, I noticed that I was starting to feel sick, or ill, like there was something not quite right with me roughly a year before my persistent MAs started happening. I would get hungry more often and started to have what seemed like diabetes-like symptoms, but of course (and thankfully), didn’t have that either. During the year before my persistent MAs I found that it was more difficult to concentrate than usual, I had to eat more frequently, and I would have these horrible dizzy spells (that later turned into the visual MA spells). The floaters in my eyes and the phosphenes only came a few months after the persistent MAs started happening.
I am nearly convinced that what we have is some yet, unrecognized persistent disease not altogether different from ones such as bipolar disorder, schizophrenia, or epilepsy. Our disease does not really have a name nor is much known about what causes it, but I definitely felt like there was a definite period of onset when I started feeling ill and now that I have this disease I’ve never felt the same as I did before I got it. Floaters everywhere, constant worry about the next MA, and an inability to fine tune my lifestyle and diet to avoid getting too many of these MAs.
March 16, 2009 at 6:48 pm
Hi, Howard,
Thank you for your comment. I apologise for the delay in approving it, but I am having computer problems.
It seems that most people who have PMA have anxiety about the condition. While I firmly believe that it is related to migraine (I have frequent ones), I do wonder whether the depersonalisation/derealisation is necessarily due to anxiety about PMA. I also have occasional panic attacks, yet am not concerned by PMA. Having both these “neurotic” symptoms, yet not being worried about having PMA or migraine I do question that the idea that panic/anxiety attacks and depersonalisation/derealisation are anxiety disorders in the jargon that are “sequelae” (result from) anxiety. If you follow? My own suspicion is that they are a direct co-symptom of the underlying migraine condition.
I do think that migraine (and PMA with it) covers a range of conditions, not necessarily of a single cause. But on both this and the above point I am not medically qualified.
I hope that your experience improves. It is a reassuring thought that usually migraine symptoms become less frequent and less severe with age.
Take care.
March 24, 2009 at 10:00 pm
Thanks for the reply. I know I definitely have a large degree of anxiety that comes with each MA attack, but it seems like it’s more like a phase that accompanies a specific portion of the aura than me actually being afraid of anything. Still an interesting question that you posed about whether it is idiopathic in nature or not.
I do have a question for you, though. You mentioned in one of your earlier posts that floaters can accompany PMA. Since floaters originate in the vitreous humor of the eye and MAs occur in the occipital lobe of the brain, how could floaters be related to MAs? What is your theory? I’d be interested if you could speak to that question when you have time.
Thanks,
Howard
March 25, 2009 at 7:24 pm
Hi, Howard,
I think floaters (and blue field phenomena) can be experienced by anyone, not just aura sufferers or those with any eye or neurological condition. In May, circumstances allowing, I want to do a review of the site and will look again at this. I’m sorry if what I have written has caused any confusion. I’ll check that then. But it’s important to remember, as I keep saying(!), that I have no medical training or anything. I’m just a sufferer myself blogging about my own experience and trying to find reliable sources on what seems a condition it’s hard for lay people like us to find much about. I guess it may be that persistent aura sufferers talk about floaters and other unrelated conditions because, like me, we tend to notice any irregularity in vision!
Take care.