Visual snow syndrome and neck instability

Ross Hauser, MD

Visual snow syndrome is something that many patients describe to us as ONE of their many symptoms. A typical patient story where visual disturbance is present will be described in somewhat this manner:

The patient would have visited multiple specialists without any explanation as to why his/her vision is blurry and can not be focused. The patient will report that various eye specialists ran a series of various diagnostic tests looking for any hint or clue as to what was causing the visual disturbances. Most if not all these people’s tests came back negative.

The patient will then report that they saw a Neurologist and ENT doctor and were given various medications including antibiotics, B12 shots, and steroids without help. MRI with and without contrast of the head, neck, and MR angiogram of the neck with and without contrast all were negative. Eventually, a chiropractor will be consulted. For many people, it is the chiropractor who identified cervical spine instability as a possible culprit.

Please see my companion article Chronic Neck Pain and Blurred or Double Vision Problems

Often we will hear from people who see visual snow even with their eyes closed, they also have the more classic symptoms of photophobia, hallucinations, loss of night vision, halos, floaters, trailing or ghosting images. Blurred vision, visual snow syndrome, Palinopsia, Enhanced entoptic phenomena (including eye floaters and blue field entoptic phenomenon – the appearance of floating dots, especially when looking up at the sky or a blue screen), Nyctalopia (poor vision in dim light or darker environments), and difficulty focusing are very common eye complaints that many people have are have a diagnosis of atlantoaxial instability or lower cervical instability. Further diagnosis of fibromyalgia, tinnitus, migraine, dizziness, persistent postural-perceptual dizziness (PPPD), common in visual snow syndrome is common comorbidities in cervical spine instability.

Article summary

When Visual Snow Syndrome causes painful vision.
“Because the pathophysiology (of visual snow syndrome) is unclear, the treatment course is also unclear.”
Visual Snow Syndrome can be caused by many things – not just one problem.
Post-Concussion Syndrome and Visual Snow Syndrome.
The connection between Visual Snow Syndrome and migraine.
From pupil to the brain – a disconnect in the visual network.

When Visual Snow Syndrome causes painful vision

A January 2023 paper in the journal Headache (1) confirmed that people with visual snow syndrome are hypersensitive to painful light simulation. The researchers noted: “. . . results suggest that sensory hypersensitivity may be prevalent in people with visual snow syndrome and indicate that visual allodynia is associated with increased severity of visual snow syndrome. Additionally, our findings indicate that the inclusion of cases of latent (asymptomatic or very manageable symptoms) visual snow syndrome in future research may be important for researchers to develop a more complete understanding of the perceptual experiences of people with visual snow syndrome.” What is being suggested is that “some people who meet the criteria for visual snow syndrome have no awareness of it. This may be because they have lower sensory sensitivity, allowing them to ignore their visual phenomena.” Here the challenge is why are some symptomatic, why are some asymptomatic, and what triggers the symptoms that become debilitating.

“Because the pathophysiology (of visual snow syndrome) is unclear, the treatment course is also unclear.”

The challenges of nothing working is demonstrated in a January 2022 case study presented in the journal Optometry and Vision Science (2)

In this case, a 40-year-old white male is described as developing symptoms of constant pulsating pixels (Oscillopsia) throughout his entire visual field approximately three weeks after a series of mild concussions. Additionally, he experienced persistence of images (Palinopsia) and photosensitivity (sensitivity to light sources).

“The patient had normal eye exams, visual fields, and retinal imaging. Brain magnetic resonance imaging, magnetic resonance angiography, electroencephalography, and cerebrospinal fluid analysis were unremarkable.

A positron emission tomography scan demonstrated hypometabolism in the posterior parietal lobes (the area in the brain where objects in space are identified and eye movement commands are centered) and left posterior cingulate gyrus (in simplest terms an area of the brain that processes information).

Pharmacological treatment with anti-epileptic and migraine medications was unsuccessful.

Tinted lenses were essentially ineffective with a 10% reduction in symptoms reported with the use of a custom blue-tinted lens.

Vision rehabilitation aids with optical character recognition were utilized for prolonged reading needs.”

Conclusions: “The pathophysiology is still unclear at this point with evidence suggesting a link to the secondary visual cortex, specifically the lingual gyrus. More studies are needed to determine the exact cause, especially studies that separate visual snow syndrome patients with and without comorbid migraine. Because the pathophysiology is unclear, the treatment course is also unclear.”

Visual Snow Syndrome can be caused by many things – not just one problem.

People who suffer from post-concussion syndrome can suffer from Visual Snow Syndrome. People who suffer from Visual Snow Syndrome may have never suffered from a concussion. Some people who suffer from Visual Snow Syndrome may suffer from migraines. Some people with migraines do not have Visual Snow Syndrome. Some people who have tinnitus may suffer from Visual Snow Syndrome. Some people who have tinnitus do not suffer from Visual Snow Syndrome.

A February 2018 paper in the journal Current Opinion in Neurology (3) explained that doctors cannot pinpoint a clear understanding of this problem nor test hypotheses about treatment.

“Recent evidence suggests visual snow is a complex neurological syndrome characterized by debilitating visual symptoms. It is becoming better understood as it is systematically studied. Perhaps the most important unmet need for the condition is a sufficient understanding of it to generate and test hypotheses about treatment.”

In May 2021 the same lead author and co-authors wrote of the development of an idea where the problem of visual snow syndrome was coming from. Here is what they published in the journal Human Brain Mapping. (4) “Our results suggest that visual snow syndrome is characterized by a widespread disturbance in the functional connectivity of several brain systems. This dysfunction involves the pre-cortical and cortical visual pathways, the visual motion network, the attentional networks, and finally the salience network (the network that “gets your attention” makes you aware of a stimulus like a falling object or someone yelling your name); further, it represents evidence of ongoing alterations both at rest and during visual stimulus processing.”

Visual snow syndrome is a “network disorder”

Following along this theme of understanding that visual snow syndrome can be the result of many problems and co-mingle with other symptoms and conditions is a paper from the Department of Neurology at Bern University Hospital in Switzerland that speculated that visual snow syndrome is a “network disorder.” This was published in the journal Frontiers in Neurology (5) in October 2021.

First here is some background of this research:

Patients with visual snow syndrome suffer from a continuous visual disturbance resembling the view of a badly tuned analog television (i.e., VS) and other visual, as well as non-visual symptoms. This explanation and visual of a TV with snow are necessary because some of our patients even those 30 years old may not know what an analog or antenna TV is or was.

In the image below – a TV with no signal – you get “snow.”

According to the study authors: “These symptoms can persist over years and often strongly impact the quality of life. . . Presently, there is no established treatment, and the underlying pathophysiology is unknown. In recent years, there have been several approaches to identify the brain areas involved and their interplay to explain the complex presentation.”

“In visual snow syndrome, the clinical spectrum includes additional visual disturbances such as excessive, palinopsia, nyctalopia Inability to see at night), photophobia, and entoptic phenomena. There is also an association with other perceptual and affective disorders as well as cognitive symptoms.”

An April 2023 study from the University of Melbourne in the journal Human brain mapping (6) “identified functional network disturbances in VSS patients. Specifically, in VSS patients, measures of network integration (eigenvector centrality – in simplest terms the influence on the network that creates bad signals) and network segregation (local efficiency and modularity – in simplest terms – the ability to give or not be able to give priority to more important or corrective signals) were both affected, indicating less flexibility in basal (voluntary movements) and essential aspects of a network.”

From pupil to the brain – a disconnect in the visual network. What is displayed in this image?

The Superior cervical sympathetic ganglion (the nerve center that provides innervation to the head and neck) and pupillary dilation. Postganglionic axons (in simplest terms nerve fibers) of the Superior cervical ganglion innervate the eye, lacrimal (tear) gland, and pupillary dilator muscle which dilates the pupil.

When a stimulus (possibly a cervical disc herniation, impingement, or compression) causes superior cervical sympathetic ganglion activity to go hyperactive or disturbed this constant pupillary dilation can cause photophobia (sensitivity to light) and ultimately increased intraocular pressure since the Superior cervical sympathetic ganglion sits right in front of the C2 – C3 joint. When C2 – C3 instability is present, it is a likely structural cause of vision problems.

If one considers idiopathic intracranial hypertension, which is increased intracranial pressure for no apparent reason, it makes sense to consider cervical instability. The condition causes moderate to severe headaches that often originate behind the eye and are worse with eye movements because the condition can cause swelling in the optic nerve and even blindness. Ringing in the ears that pulse in time with your heartbeat (pulsatile tinnitus), nausea, vomiting, or dizziness are common symptoms. Of course neck, shoulder, and back pain are common and many have other visual symptoms including blurred or dimmed vision, photopsia, or seeing light flashes, again because of the optic nerve swelling.

In the image below the caption reads:

Seeing multiple images at a time after the stimulus has been removed is palinopsia it seemed quite common with upper cervical instability-induced intracranial hypertension caused by the increased fluid or pressure around the nerve making nerve impulses coming from the right eye reach the brain at a different time than those coming from the left eye. At our center, successive restoration of the cervical lordotic curve and stability by a combination of curve correction and Prolotherapy this condition can be resolved. These treatments will be discussed below.

Returning to the University of Bern research: The studies that have been included in this review demonstrate structural, functional, and metabolic alterations in the primary and/or secondary visual areas of the brain. Beyond that, results indicate a disruption in the pre-cortical visual pathways and large-scale networks including the default mode network and the salience network.

Discussion: The combination of the clinical picture and widespread functional and structural alterations in visual and extra-visual areas indicates that VSS is a network disorder. The involvement of pre-cortical visual structures and attentional networks might result in an impairment of “filtering” and prioritizing stimuli as a top-down process with subsequent excessive activation of the visual cortices when exposed to irrelevant external and internal stimuli.

The caption of this image reads: Cervical instability can have many negative effects on the eye including the interruption of vision as seen in eye floaters.

Visual snow syndrome is not caused by one thing but rather by a group of things

This is how the University of Bern study concluded:

“Already from a clinical perspective, the symptoms of Visual snow syndrome cannot be attributed to a single brain area or a functional unit. Rather, there is evidence of a network disorder that might manifest as a disturbance in coordination or interaction between different parts of the visual system causing a loss of inhibitory modulation and thereby hyperactivity in the primary and secondary visual cortex.

“There are potentially common underlying mechanisms.”

“Visual snow syndrome seems to be a spectrum disorder with different degrees of severity, e.g., defined by the number of additional symptoms. There is an association with tinnitus thought to be caused by cortical hyperexcitability and the production of a phantom sensation. Several patients may suffer from comorbid fibromyalgia, the classical centralized pain disorder with hypersensitivity to external stimuli. There are potentially common underlying mechanisms.”

There is very much to consider here so first let’s understand some of the terms used in this study.

Hyperactivity in the primary and secondary visual cortex.
- The primary visual cortex is the cortical (thinking) region of the brain that receives and processes visual information from the retinas.
- The secondary visual cortex receives information from the primary visual cortex and helps construct the visual association area. (The understanding of what we are seeing).

The suggestion is that there may be a disturbance between the retinas and the visual cortex. In some people, we may consider this the “missing diagnosis.” What is causing this disruption? The answer may be cervical instability.

Post-Concussion Syndrome and Visual Snow Syndrome

Many of the people that contact us via email will not ask questions concerning visual snow syndrome. They will ask questions about their post-concussion syndrome. Among the long list of symptoms will be a mention of visual snow syndrome.

Here are some examples

Post-Concussion Syndrome (PCS) is my primary concern. I suffered a concussion a few months ago and I still have many symptoms that have not gone away. I have constant dizziness, neck pain, suboccipital pain, headaches (on most days), tinnitus, vertigo when I turn my head to the right and look down, increased dizziness with any kind of head movement, tunnel vision, brain fog, concentration issues, sensitivity to light and sound, pupillary hippus, visual snow, motion sensitivity, frequent ear pain in one ear or both ears and jaw pain.

I also hear cracking whenever I move my neck, even if it’s only a slight movement of the neck. It has become common for me to feel a buzzing or an “electrical sensation” in my arms and legs which makes me feel anxious. I am also very sensitive to temperatures now. My hands are feet are always cold.

The connection between Visual Snow Syndrome and migraine

A February 2023 study in the journal Eye (7), offered connections between migraine and the phenomena of visual snow syndrome. The authors noted that since described as a clinical entity, visual snow syndrome has been linked to migraines. Initially, visual snow syndrome was thought to be a complication of migraine, further research demonstrated that it was a separate entity. Also noted was that migraine does aggravate the problem of visual snow syndrome and typically migraine treatments do not alleviate the symptoms of visual snow syndrome. Further, “Photophobia, the perception of normal light being either too bright or painful, is a hallmark symptom of both migraine and visual snow syndrome, representing an important pathophysiological (causes and effects) and clinical link. Light sensitivity can be present in migraine both during attacks and (spikes), and a continuous hypersensitivity to light is reported in more than half of visual snow syndrome individuals. In fact, in a case-control study, visual snow syndrome photophobia was shown to be independent of concomitant migraine, with levels of perceived visual sensitivity similar to those of chronic migraine patients. (Visual snow syndrome and migraine symptoms are similar and independent.)

The answer may be cervical spine instability

“I developed Visual Snow Syndrome . . . My symptoms included intense vertigo, light sensitivity, visual static, afterimages, double vision, self-light of the eye, visual confusion on looking at patterns, and tinnitus. I have very poor posture and head forward position. Acupuncture for migraines temporarily relieves symptoms.”

The difficulties of understanding visual snow syndrome have been demonstrated in some of the most recent research listed above. It is a condition that can be multi-factorial in its cause. It can also have an underlying cause. One underlying cause presented here is cervical spine instability. Why cervical spine instability?

Multiple areas of cervical instability

In one specific case, we had a patient who on his initial consultation with us complained of blurred vision (worse at night), double vision, a feeling off-balance, constant crepitus with neck movement, tinnitus mostly in the left ear, a feeling of fullness in both ears, left posterior shoulder pain and trouble sleeping. His symptoms seemed to be worse when rotating his head left or right. He was unable to drive at night and was unable to play golf. He had a constant 4/10 throbbing headache posterior upper neck. A digital motion x-ray at our facility revealed multiple areas of cervical instability including significant anterolisthesis of C2-C3, C4-C5, and C5-C6, as well as gapping of facet joints bilaterally at C4-C5 and C5-C6, encroachment of the facet joint at C3-C4 and C4-C5 on the left with flexion and extension, as well evidence of overhang on lateral flexion of C1-C2. I will describe this patient’s treatment and case history below.

In the image below the neck-eye reflexes are described.

These reflexes keep the head balanced while a person is watching moving objects or the body or head is in motion.

The reflex vestibulo-ocular (VOR) causes eye gaze stabilization during head motion
The reflex cervico-ocular (COR) helps the eyes to move in relation to neck rotation, (because of cervical ligament and facet joint proprioceptors – neurons that sense motion.)
The reflex vestibulocollic (VCR) helps to stabilize the head in space when the body moves.
The reflex cervicalcollic (CCR) muscles tightened to stabilize the head (because of cervical ligament and facet joint proprioceptors – neurons that sense motion.)

Potentially all these reflexes are impaired with ligament cervical instability causing symptoms of vertigo, dizziness, Nystagmus, Oscillopsia, visual disturbance, and poor balance.

Ross Hauser, MD discusses vision problems from vagus nerve injury and how these can be caused by cervical instability and resolved with Prolotherapy and curve correction.

What are we seeing in this image?

A Digital Motion X-Ray or DMX is a tool we use to help understand a patient’s neck instability and how we may be able to help the patients with our treatments. In the illustration below a patient who suffered from upper cervical instability demonstrated hypermobility of the C1-C2. This hypermobility can result in common symptoms of neck pain, headaches, dizziness, vertigo, tinnitus, concentration difficulties, anxiety, TMJ, vision disturbances, and other symptoms.

The curvatures of the neck -What are we seeing in this image?

In our practice, we see problems of cervical spine instability caused by damaged or weakened cervical spine ligaments. With ligament weakness or laxity, the cervical vertebrae move out of place and progress into problems of chronic pain and neurological symptoms by distorting the natural curve of the spine. This illustration demonstrates the progression from Lordotic to Military to Kyphotic to “S” shape curve.

In this video, a demonstration of treatment is given

Prolotherapy is referred to as a regenerative injection technique (RIT) because it is based on the premise that the regenerative healing process can rebuild and repair damaged soft tissue structures. It is a simple injection treatment that addresses very complex issues.

This video jumps to 1:05 where the actual treatment begins.

This patient is having C1-C2 areas treated. Ross Hauser, MD, is giving the injections.

Summary and contact us. Can we help you? How do I know if I’m a good candidate?

1 Thompson AC, Goodbourn PT, Forte JD. Perceived severity of Visual Snow Syndrome is associated with visual allodynia. Headache: The Journal of Head and Face Pain. 2023 Jan 27. [Google Scholar]
2 Werner RN, Gustafson JA. Case Report: Visual Snow Syndrome following Repetitive Mild Traumatic Brain Injury. Optometry and Vision Science: Official Publication of the American Academy of Optometry. 2022 Jan 7. [Google Scholar]
3 Puledda F, Schankin C, Digre K, Goadsby PJ. Visual snow syndrome: what we know so far. Current opinion in neurology. 2018 Feb 1;31(1):52-8. [Google Scholar]
4 Puledda F, O’Daly O, Schankin C, Ffytche D, Williams SC, Goadsby PJ. Disrupted connectivity within visual, attentional, and salience networks in the visual snow syndrome. Human brain mapping. 2021 May;42(7):2032-44. [Google Scholar]
5 Klein A, Schankin CJ. Visual Snow Syndrome as a Network Disorder: A Systematic Review. Frontiers in neurology. 2021:1708. [Google Scholar]
6 Strik M, Clough M, Solly EJ, Glarin R, White OB, Kolbe SC, Fielding J. Brain network dynamics in people with visual snow syndrome. Human Brain Mapping. 2022 Dec 8. [Google Scholar]
7 Silva EM, Puledda F. Visual snow syndrome and migraine: a review. Eye. 2023 Feb 14:1-5. [Google Scholar]