Visual Snow

Marsha Sorenson, ODTimothy C. Hain, MD•Page last modified: February 20, 2020

Visual Snow syndrome consists of the perception of "snow" -- namely dots, pixellated fuzz, bubbles or static in vision (Ciuffreda et al, 2019). There has been considerable interest in this phenomena recently(Puledda et al, 2018), possible related to social media buzz. Prior to 2014, there were fewer than 10 cases in the entire medical literature (Metzler and Robertson, 2018).

Visual Snow is often found in combination with Migraine. It is sometimes accompanied by four other phenomena:

In patients with migraine, these symptoms may represent just a part of the general tendency to have greater responses to sensory inputs than normal.

Diagnosis

To evaluate visual snow, a complete eye exam is needed to rule out any ocular health problems. Additional testing including corneal topography, Optical Coherence Tomography (OCT) may be recommended to rule out other conditions. Saccadic eye movements should be evaluated to determine if a patient will benefit from vision therapy to reduce palinopsia.

There is also some data in the literature that the disorder is usually accompanied by a reduction of visual habituation, that can be detected using visual evoked potentials.

Chicago dizziness and hearing evaluates and treats patients with visual snow in our "visual vertigo" clinic.

Mechanism of visual snow

Visual snow is generally thought to be due to a central (brain) disturbance with lowered thresholds for perception in the visual cortex, or lack of habituation.

Treatment

Treatment for visual snow can be broken down into ocular interventions and medicine.

Ocular interventions(Optometric treatments) to improve quality of life in patients with visual snow include tinted lenses and optometric vision therapy. Tinted filters may help reduce the perception of visual snow, changing light characteristics or decreasing luminance may reduce the appearance of visual snow. Gray, FL-41 (a shade of pink) or blue-blocking lenses (yellow) may help make visual snow less bothersome.

Medical interventions are usually medications that modify migraine, such as seizure medications. Examples include

Review of papers regarding treatment of visual snow (not so many of these !):

Our experience with treatment:

At CDH, we usually consider visual snow to be related to migraine. Migraine contains within it a large number of sensory sensitivities, not always accompanied by headache, and with a larger repertoire of medications aimed to stabilize irritable cortical circuits. In one case, a man in his 30's complained of --

"symptoms are worsened by certain audio frequencies, or noisy locations like busy restaurants. Unnatural light sources are a major problem. I originally thought fluorescent light was the
worst, but LED is AWFUL. I can perceive the high frequency strobing of LED lights, and it absolutely drains me. Weather and/or changes in pressure can affect me. Sometimes even smells seem to set me off. At its worst, stationary objects, especially patterns or text on posters will appear to shake or jiggle." The smell sensitivity is particularly suggestive of migraine (Kelman, 2004). His visual snow largely vanished after adding magnesium supplements to his regimen. Magnesium is generally safe, and helps in stabilizing neural circuits.

References: