Author: Maartje van Meijel

December 13, 2025 – For people living with Visual Snow (Syndrome), it is often difficult to put into words how much impact their symptoms have. Not just that the symptoms are there, but what they do to everyday functioning, concentration, sleep, and mental wellbeing. This is precisely what makes it so hard to receive appropriate care or to assess treatments fairly.

A new international study, published in Frontiers in Neurology, takes an important step forward in this area. The study evaluates an updated questionnaire: the Colorado Visual Snow Survey 2.0 (CVSS 2.0). This survey is designed to systematically capture which VSS symptoms a person experiences, how severe they are, and how strongly they affect daily life.

Why is this important?

Visual Snow Syndrome has only relatively recently been recognised as a neurological condition. Until now, there have been very few reliable tools that allow patients to report their symptoms and limitations in a way that is also useful for research and clinical care. This is a major problem: without proper measurement tools, it is almost impossible to test treatments or to objectively track improvement—or deterioration—over time.

The CVSS 2.0 aims to fill this gap.

What exactly is measured?

The survey does not focus solely on visual static (“snow”), but looks at a broader range of symptoms that many people with VSS recognise, including:

• afterimages and visual trails
• blue field entoptic phenomenon (moving light dots against a blue background)
• floaters
• night vision difficulties
• tinnitus
• and non-visual symptoms such as depersonalisation/derealisation, anxiety and low mood (note: anxiety and low mood as a consequence of symptoms)

For each symptom, four aspects are assessed:
its intensity, how much it interferes with screen use, how much it interferes with everyday visual environments, and to what extent it limits daily activities. This last aspect is crucial, as it highlights that VSS is not only a perceptual issue, but a condition that can profoundly affect daily functioning.

What were the findings?

The researchers compared people with Visual Snow to a control group without VSS. The results were clear:

The CVSS 2.0 strongly differentiated between people with and without VSS. People with a formal diagnosis and those without a diagnosis (but with clear VSS symptoms) scored almost identically. This reinforces what many patients already know: the absence of an official diagnosis says very little about the severity of symptoms.

In addition to visual static, the strongest predictors of Visual Snow were night vision problems, blue field entoptic phenomenon, afterimages, and tinnitus. Notably, tinnitus scored highly as a distinguishing symptom, even though it is not currently part of the official international diagnostic criteria. The authors suggest that this may warrant reconsideration.

Mental health symptoms are not secondary

The study also pays attention to symptoms such as depersonalisation/derealisation, anxiety and low mood. These were clearly more frequent and more severe in people with VSS than in controls. The researchers stress that these symptoms deserve serious attention in the care of VSS patients—not as a “psychological explanation” for the condition, but as part of the overall disease burden and quality of life.

In other words, mental health symptoms are not peripheral; they may be a logical consequence of prolonged neurological overload and continuous visual disturbance.

What does this mean for patients?

This study does not offer a treatment or a direct solution. However, it does provide an important foundation. Better measurement tools are essential to:

• fairly evaluate treatments,
• make the severity of symptoms visible to clinicians,
• and finally determine whether interventions genuinely help.

For patients, this may represent a step towards greater recognition, better communication with healthcare professionals, and ultimately improved care.

Why Visual Snow Europe is sharing this

At Visual Snow Europe, we believe it is essential that research does not remain confined to academic journals, but is shared in a way that is accessible to the people it concerns. Studies like this show that Visual Snow Syndrome is being investigated in an increasingly serious and systematic manner—and that patient experience plays a central role in this progress.

We remain committed to raising awareness, improving diagnostics, and supporting research that reflects the real-life experiences of people living with Visual Snow Syndrome.

More information about this study can be found here.
Visual Snow Europe Foundation was not involved in this research.

January 24, 2025 – Visual Snow Syndrome (VSS) has now been officially recognized with a unique code in the eleventh edition of the International Classification of Diseases (ICD-11) by the World Health Organization (WHO). This significant milestone is the result of collaborative efforts by the Visual Snow Initiative (VSI), led by founder Sierra Domb, in partnership with prominent neurologists such as Dr. Peter Goadsby and Dr. Owen White.

The assignment of an ICD code to VSS has far-reaching positive implications for both patients and the global medical community. It acknowledges VSS as a legitimate neurological disorder, which will enhance the accuracy of diagnosis and treatment. Furthermore, this recognition enables healthcare services related to VSS to become eligible for insurance coverage and financial support. It will also stimulate further research into VSS, potentially leading to better treatment methods and a deeper understanding of the condition.

Beginning in 2025, Visual Snow Syndrome and its associated symptom, Visual Snow, will be officially included in the ICD-11. This acknowledgment marks a turning point for everyone affected by VSS and offers hope for improved care and understanding in the future.

September 17, 2024 – A new study investigating the effectiveness and safety of medication for the treatment of Visual Snow Syndrome (VSS) is being investigated. The goal of this study is to discover whether pharmacological treatment, or medication, can safely address the specific deficits associated with VSS, alleviate visual symptoms and thereby improve patients’ quality of life.

This groundbreaking research is a collaboration between Visual Snow Initiative and well-known VSS neurologists, other Dr. Peter Goadsby, Dr. Francesca Puledda, Dr. Christoph Schankin and Sarah Aeschlimann. The identification of medications with therapeutic potential to treat VSS could represent a breakthrough in clinical practice. If researchers succeed in identifying a medication that proves to be effective, it could form the basis for the first effective pharmacological treatment options for VSS patients.

This new clinical trial will take place at the University Hospital of Bern, Department of Neurology, in Switzerland. After submission of an ethics application and approval by Swissmedic, recruitment for the study will begin. The expected completion of the study is July 2025. Administration of the medication and possible side effects will be carefully monitored by VSS researchers with expertise in the condition to ensure the safety of participants. They will regularly measure the severity of VSS, reduction in symptoms, quality of life and any side effects.

Despite intensive efforts, the development of effective pharmacological therapies for VSS has remained a challenge. Medications tested to date were considered ineffective by researchers, with symptoms usually worsening or no changes occurring. Although some individuals with VSS have reported that certain medications have helped them, there is no clinical evidence to support an effective pharmacological treatment for VSS. Researchers needed more insights into the cause and pathophysiology of VSS before they could identify possible targeted and effective treatments.

Recent studies had revealed new crucial information about the cause, pathophysiology, symptomatology and mechanisms of Visual Snow Syndrome as a network disorder. By comparing the distribution of receptors in different brain regions and functional connectivity patterns, a recent study was able to identify changes in the serotonergic and glutamatergic neurotransmitter systems that may contribute to the pathophysiology of VSS. In this new clinical trial, researchers will investigate the potential effectiveness and safety of medications that target the specific deficits associated with VSS.

We’ll keep you up to date as soon as more news is known.

May 7, 2024 –

Dr. Schankin and Dr. Klein of Inselspital Bern (Switzerland) will initiate a new study on neuromodulation for VSS. This research investigates how transcranial alternating current stimulation (tACS) can modulate overactive neural networks in the brain, potentially leading to new treatment options for VSS. Dr. Schankin and Dr. Klein’s techniques are aimed at reducing several common VSS symptoms, including visual snow/static, palinopsia, entoptic
symptoms, photophobia and nyctalopia.

The underlying idea behind VSS is that multiple neural networks in the brain remain overactive, bombarding the visual system with excess information. TACS, however, offers the ability to modulate these networks. Dr. Schankin and Dr. Klein’s primary goal is to pinpoint the specific areas of the brain where something is not functioning properly. To accomplish this, they are combining several diagnostic markers with a treatment-oriented methodology.

Their research will begin with a comprehensive visual test, MRI and electroencephalogram (EEG) measurements. Dr. Schankin and Dr. Klein are particularly interested in observing how this stimulation affects VSS symptoms, how it affects performance on tasks and whether there are changes in EEG patterns in patients with VSS.

August 11, 2023: Researchers from King’s College London are sharing their latest discovery: The activity of glutamate and serotonin differs in individuals with VSS compared to those without the condition, potentially triggering the identification of biomarkers and fostering hope for future pharmacological treatments.

Visual Snow Syndrome (VSS) has long mystified researchers due to its poorly understood neuropharmacological underpinnings. Seeking to demystify this perplexing condition, a pioneering study harnessed the power of cutting-edge technology. By combining receptor target maps with functional magnetic resonance imaging (fMRI) data at rest, the goal was to decipher which neurotransmitters might be orchestrating the brain circuits linked to VSS.

The study employed a novel technique called Receptor-Enriched Analysis of Functional Connectivity by Targets (REACT). This innovative approach delved into the intricate functional networks influenced by five distinct neurotransmitter systems. Participants included individuals with VSS (n = 24), healthy controls (HCs; n = 24), and migraine patients (MIG; n = 25, including 15 with migraine with aura [MwA]). REACT utilized receptor density templates for pivotal neurotransmitter receptors and transporters, such as noradrenaline, dopamine, serotonin, GABA-A, NMDA, 5HT1B, and 5HT2A. These templates facilitated the creation of personalized, voxel-level functional connectivity (FC) maps. These individualized maps were then meticulously compared across the three groups: HCs, MIG, and VSS.

Fascinating outcomes emerged from this exploration. Individuals grappling with VSS exhibited diminished FC within glutamatergic networks situated in the anterior cingulate cortex (ACC). This divergence was evident when juxtaposed with both HCs and patients with migraines. Moreover, a notable reduction in FC within serotoninergic networks surfaced in regions like the insula, temporal pole, and orbitofrontal cortex. These patterns mirrored observations made in individuals with migraine with aura. Of significant interest, VSS patients showcased reduced FC within networks rich in the 5HT2A receptor. These networks were primarily located in occipito-temporo-parietal association cortices. Subgroup analyses revealed that these alterations were not only independent of migraine influences but also akin to changes seen in patients with migraine with aura.

This study’s implications are far-reaching. It highlights the pivotal roles of glutamate and serotonin in rewiring brain connectivity, impacting domains associated with visual processing, salience detection, and emotional responses within the context of VSS. Importantly, altered serotonergic connectivity in VSS stands on its own, unrelated to migraines. Nonetheless, the striking resemblance to patterns seen in migraine with aura underscores a shared biological foundation between these distinct disorders.




(Source: ANN NEUROL 2023)