Visual Snow History

> Visual Snow History
Old Problem, New Understanding

Advancing from Uncertainty to Understanding

Historical Challenges in Diagnosing Visual Snow Syndrome (VSS)

Obtaining an accurate diagnosis for Visual Snow Syndrome (VSS) has historically been a significant challenge. Due to its visual presentation, individuals experiencing symptoms—and many physicians—initially assumed the problem originated in the eyes. However, referrals to optometrists and ophthalmologists often led to normal clinical findings. This is because VSS is not an eye disease; it is a neurological sensory processing condition that affects visual perception and originates in the brain.

Early Clinical Documentation of Visual Snow

The earliest known clinical reference to visual snow appears in the Transactions of the American Ophthalmological Society (1944). Frank D. Carroll reported six patients who developed persistent visual disturbances following digitalis administration, a medication prescribed for cardiac conditions. Symptoms included “snowy vision,” flashing lights, flickering, flowerlike images, green/yellow visual tints, and colored floaters. Comprehensive eye examinations revealed no abnormalities. Carroll theorized that digitalis impacted the central nervous system, specifically the cerebrum, resulting in these visual phenomena.

Misclassification and Marginalization of VSS

Despite these early observations, Visual Snow Syndrome remained unrecognized for decades. Medical education did not address the condition, and most physicians were unaware of its existence. Among those familiar, VSS was often misclassified as a variant of migraine or mistakenly attributed to psychological factors.

A landmark 1995 study, Persistent Positive Visual Phenomena in Migraine (Liu et al., Neurology), described patients experiencing persistent visual static across the visual field, lasting months to years, despite normal neurological and ophthalmological findings. Although initially considered a migraine-related phenomenon, the continuous, broader symptom profile aligned more closely with what is now formally identified as Visual Snow Syndrome. This study helped pave the way for distinguishing VSS from migraine aura.

While VSS may coexist with migraine in some cases, many individuals develop VSS independently. Unlike migraine aura, which typically resolves, VSS symptoms are continuous and persist 24/7, regardless of headache presence.

From Skepticism to Scientific Validation

For many years, VSS was misinterpreted, dismissed, or incorrectly associated with psychiatric conditions—an outdated and scientifically refuted view. This widespread misunderstanding delayed diagnosis, contributed to stigma, and negatively impacted the mental health of those affected.

However, some physicians recognized VSS as a distinct neurological condition. Yet, due to the absence of targeted research, diagnostic criteria, and treatment protocols, clinical management options were limited.

Formal Recognition and Advancements in Research

Today, Visual Snow Syndrome is formally recognized as a distinct neurological disorder involving both visual and non-visual sensory processing. Visual Snow Syndrome (the disorder) and Visual Snow (the symptom) each have formal diagnostic codes within the International Classification of Diseases, 11th Revision (ICD-11), established by the World Health Organization (WHO). This major milestone was achieved following advocacy efforts and expert testimony from Visual Snow Initiative (VSI) Founder Sierra Domb, along with renowned researchers Dr. Peter Goadsby and Dr. Owen White.

The development of formal diagnostic criteria and advances in neuroimaging and clinical research have improved diagnostic accuracy and reduced rates of misclassification. Collaborative efforts between VSI and leading medical researchers have clarified the differences between VSS and migraine, enhancing clinician education and improving patient outcomes.

Global Research Initiatives and Expanded Resources

Global research efforts funded by the Visual Snow Initiative (VSI) have taken place across multiple countries, driving forward understanding of the biological mechanisms, pathophysiology, and potential treatments for VSS. These international collaborations have been instrumental in validating VSS as a legitimate neurological condition and informing new therapeutic strategies.

Resources that were once unavailable are now accessible to the VSS community, including diagnostic guidelines, a global directory of physicians familiar with VSS, and noninvasive treatment options based on emerging scientific findings.

Since VSI’s founding in 2018, global awareness, education, and research regarding VSS have expanded dramatically, leading to a quadrupling of recognition across clinical and public domains.

Moving Forward: Continued Progress in Awareness and Research

Continued efforts in clinical education, scientific research, and public awareness are essential to advancing diagnosis, improving patient care, identifying targeted therapies, and deepening understanding of this complex neurological condition. As research expands and understanding grows, so too does the potential to enhance outcomes and quality of life for individuals living with Visual Snow Syndrome.

Below are additional details about Visual Snow Syndrome (VSS), its history, and recent advancements in understanding, recognition, and management.

Facts and Legitimacy

The Progress:
Key Developments for Visual Snow Syndrome (VSS)

Visual Snow Syndrome (VSS): Overview

Challenges in Diagnosing Visual Snow Syndrome (VSS)

Advancements and Milestones in Visual Snow Syndrome (VSS)

Make a Difference

Support VSS Research Today

Every donation to the Visual Snow Initiative funds critical Visual Snow Syndrome (VSS) research. Your tax-deductible contribution drives global research efforts and creates a meaningful impact on the lives of those affected by VSS.