Visual Snow Syndrome Q&A

Brain Awareness Week is the global campaign to increase public awareness of the progress and benefits of brain research. In this context, we interviewed undergraduate student Sam Montoya, who works on Visual Snow Syndrome research with Stephen Engel, PhD, professor and associate chair in the Department of Psychology, and Michael-Paul Schallmo, PhD, assistant professor in the Department of Psychiatry.

What is Visual Snow Syndrome?

Visual Snow Syndrome (VSS) is a disorder in which people experience flickering specks/dots/static superimposed on the entire visual field at all times. Many describe this experience as looking similar to "television snow". In addition to the “snow” itself, other symptoms of VSS include strong afterimages, streaks left behind moving objects, light sensitivity, blue field entoptic phenomena (when the source of the visual effect is within the eye itself), poor night vision, tinnitus (ringing/buzzing in the ears), and migraine. These symptoms can interfere with daily tasks such as driving and reading.

Can you briefly describe your research?

We will contribute to the understanding of VSS by quantifying the "snow" so that we can answer questions like “how consistent is someone's ability to simulate their snow” and “how uniform is this experience across individuals.” We developed a matching task in which participants with VSS can adjust parameters of simulated visual snow on a computer screen to match their visual snow percept. Additionally, we are studying whether visual snow can be relieved by watching videos that adapt the visual system for short periods of time.

How did you get connected to Dr. Engel and the psychology department?

I was initially drawn to Dr. Engel's research on how the visual system adapts to wearing tinted lenses. Some people with VSS have found that wearing tinted lenses can alleviate their visual symptoms, so I was excited to see someone doing research in this area. Dr. Engel is also studying a diverse set of questions spanning both basic research about how the visual system works, as well as clinical/translational research on topics like amblyopia, and age-related macular degeneration. He was very excited about my interest in studying VSS and was happy to help form a collaboration with Dr. Michael-Paul Schallmo, who studies vision through the Department of Psychiatry, and with neuro-ophthalmologist Dr. Mike Lee.

What do you hope to gain from your research?

Right now, relatively little is known about VSS. Our research will help quantify the visual snow percept. This is a fundamental step towards understanding VSS—it will allow us to further define the disorder and tell us how consistent VSS symptoms are across individuals. Our "snow matching” task could be a useful tool for diagnosis as well as an assessment of treatment effectiveness.

How can those affected by visual snow syndrome get involved in your research or connect with others in the community?

We’ve just developed a new website launching the Twin Cities Visual Snow Society. The Twin Cities Visual Snow Society is a forum to connect people with VSS, their friends, family, and allies with each other. You can also email to get involved.

If you'd like to learn more about our research on VSS, please email us at

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