Visual snow syndrome
A condition just coming to light
This condition is little understood, in part because many with the affliction don’t realize that something is amiss
Isn’t it interesting how 10 people can look at the world and see 10 different things?
Often it is perspective that varies among them, but it could also be perception.
One reader, a 34-year-old colleague at the Star, actually, wrote to Q & Ache saying she had just discovered that she sees the world differently than others: rather than seeing her surroundings in crisp, clear images, she sees them as tiny, fuzzy dots in minute, constant motion — just like static racing across an old, analog television screen.
“I see this way and had no idea everyone else didn’t see this way,” she wrote.
She asked the Star to find out what causes her condition and if there is anything she can do about it. She wanted to know: “Will it get worse?”
Before we talk about that, it’s important to note that this condition, known as Visual Snow Syndrome, has just been coming onto eye doctors’ radars.
Since it is rare — or, ophthalmologists rarely see it or know they’re seeing it — it has been under-diagnosed or simply missed as a diagnosis until now, according to ophthalmologist Yasser Khan, an eye surgeon at William Osler Health System, associate professor at Hamilton’s McMaster University and lecturer at the University of Toronto.
The newly named syndrome, called VS Syndrome for brevity, is something patients usually only complain about when it’s accompanied by other symptoms, Khan said.
While some patients may have distress because they see this way, most patients, such as my colleague, may not even know something is amiss.
“We will live with a lot,” Khan said. “People could get used to it. Or learn to ignore it.”
Aside from patients not necessarily mentioning to doctors that they see this way, another problem with diagnosing VS Syndrome, Khan said, is that standard eye exams, certain brain scans and other tests don’t pick it up.
Patients who do report seeing static or fuzziness are probably viewed as having completely normal vision. But, Khan said, there has been a tiny trickle of research that has given some insight into the phenomenon.
Recent studies using Positron Emission Tomography, a test that allows scientists to watch brain cells operating in real time, shows that certain neurons in patients with VS Syndrome are hyperexcited.
These overactive neurons, Khan said, are located in a tiny area of the brain called the lingual gyrus, which is located in a portion of the brain near the back of the head. This supplementary visual cortex, as it is called, is close to the primary visual cortex, a site that processes light into images, Khan said. The supplementary visual cortex is where higher order visual functions, such as depth perception, are manufactured.
But research is still in its infancy, so no one knows why these neurons are all worked up or what causes them to act this way, Khan said. “We don’t know what underpins it.”
The good news, he said, is that when people do complain of seeing the world in fuzzy, dynamic dots, there is now criteria for a diagnosis.
First, Khan said, doctors must rule out other possible causes of such a condition, such as an eye disease, brain tumour, trauma, or the use of hallucinogenic drugs.
If none of that exists, VS Syndrome can be diagnosed if the fuzzy vision has lasted for at least three months, is continuous and associated with at least two of the following symptoms:
Palinopsia: When patients see “after images” of objects, like a street sign, for instance, which lingers after it’s no longer in our visual field.
Entopic phenomena: These include floaters, bits of collagen that break off from the eye and swirl in the retina, casting shadows on what we see.
Photophobia: Sensitivity to bright light.
Nyctalopia: Impaired or decreased night vision.
Often, Khan said, those who com- plain of vision plagued by fuzziness and static say they’ve seen this way for as long as they can remember.
While VS Syndrome is something that evolves gradually rather than appears suddenly, it can arise when people are in their 20s, Khan said. One study from 2014 has shown that 59 per cent of patients who report visual snow also suffer from migraines, he said, and migraines may be associated with worsening of the condition.
Otherwise, Khan said, the condition may remain the same. There’s no evidence to suggest it gets worse with age.
Unfortunately, there is no cure, Khan said. But it’s early days.
For now, Khan says ophthalmologists have been treating VS Syndrome — or at least trying to control or lessen its symptoms — with three types of medications.
The first, an anticonvulsant called phenyltriazine, is used to inhibit excited cells. The other two are antihypertensive drugs, verapamil and diamox. They change blood flow to the brain to prevent migraines.
Other treatments, especially for those with light sensitivity, could include wearing sunglasses inside and outside.
It’s hard to estimate how many people have this syndrome, he said, because if patients don’t have other symptoms along with their static vision, they may not complain of anything to their ophthalmologist.
He said that raising awareness, among the public and eye doctors, will help with diagnosing this rare condition. Q & Ache is a Bi-Weekly column addressing readers’ health and wellness questions. Do you have a question about health, nutrition, fitness or being well that you can’t resolve with a Google search? Michele Henry might be able to help. Send your questions to mhenry@thestar.ca and she’ll find an expert who can answer.