ACBO President Melissa Allen with speakers Dr Charles Shidlofsky and Dr Terry Tsang.
People with visual snow syndrome constantly see the world though black and white or coloured dots. Having encountered a patient with this syndrome in her practice, optometrist Clare Campitelli attended the Australasian College of Behavioural Optometrists’ (ACBO’s) Visual Snow Syndrome conference in Sydney recently to find out more about it.
My first encounter with visual snow was in the pre-COVID era before we knew what a lockdown was – somewhere around March 2020. I remember a young high school patient who was visually irritated to the point of incapacitation by this phenomenon that he called visual snow. A type of visual static was constantly cluttering his visual experience, interfering with easy and comfortable visual processing. I wasn’t able to help resolve his symptoms at that time – it was frustrating for him and for me.
…one in 50 people have visual snow, but many do not mention it…
What Is Visual Snow?
The accepted diagnostic criteria for visual snow state that the black and white or coloured dots a patient sees must have been persisting for more than three months.
Additionally, the patient must have at least two of the following four conditions:
1. Palinopsia (persistent recurrence of a visual image and/or trailing images after the stimulus has been removed),
2. Enhanced entoptic phenomena,
3. Photophobia (sensitivity or intolerance to light, which can cause some people to avoid sunlight, computers, fluorescent lights, and car headlights), and/or
4. Nyctalopia (impaired night vision).
Additionally, the patient’s symptoms will not be consistent with typical migraine visual aura and cannot be better accounted for by another disorder.
It is estimated that one in 50 people have visual snow, but many do not mention it – either because they were born with the condition, or they have learned to live with it. However, for many people, particularly when the syndrome is acquired due to stress, brain injury, or a health condition, visual snow can severely impair the ability to work and enjoy a normal life.
The Visual Snow Syndrome conference brought optometrists together to hear from international visual snow experts Dr Charles Shidlofsky and Dr Terry Tsang.
Dr Shidlofsky who practises optometry in Texas, and Dr Tsang who has a clinic in California, described their first visual snow patients similarly. Both patients had seen many expert doctors and eurologists, had endured brain scans with CTs and MRIs, but had found no understanding, no explanation, no relief, no treatment, or hope. The common message they were given was: “There is nothing we can find wrong with your brain; your eyes look normal and healthy; we have no treatment for you.”
Echoing this sentiment, one apposite catch phrase from the weekend was that when looking for evidence of visual snow on MRI or CT scans, “It’s like we’re looking from an airplane 7,000 feet in the air rather than from down on the ground with a magnifying glass”.
Drs Shidlofsky and Tsang have extensive experience using lenses and vision therapy to rehabilitate visual systems compromised by mild brain injury, such as concussion or whiplash. They applied the approach taken to treat these patients to their first visual snow patients with promising results.
In 2018, visual snow patient Sierra Domb and her family launched the Visual Snow Initiative (www.visualsnowinitiative.org), a resource for patients who are looking for care for their visual snow and to direct research. You can access her TED talk, What is Visual Snow? Transforming Anguish into Action, at youtu.be/rsyai3GGXjs.
Transforming Anguish Into Action
With the help of the Visual Snow Initiative, Drs Shidlofsky and Tsang collaborated on a pilot study, the results of which were published in Frontiers of Neurology in December 2022.
The results from this study, The efficacy of neuro-optometric visual rehabilitation therapy in patients with visual snow syndrome, formed the basis of the ACBO conference.
As the results were discussed, Drs Shidlofsky and Tsang shed light on the questions: what is visual snow, and how do we help people with this syndrome?
Our delegates learned that:
Visual snow can be extremely distressing to the person who lives with it. The dots/static that clutter their vision are often associated with other visual symptoms, such as light sensitivity, as well as non-visual symptoms such as tinnitus, insomnia, dizziness, anxiety, and even depersonalisation – the sensation of looking down on yourself and your actions and feelings.
Neuro-visual rehabilitation can have a positive effect on quality of life (QoL) measures for these patients. At the commencement of the study, Drs Shidlofsky and Tsang had measured visual skills, including binocular vision, balance, eye tracking accuracy, as well as cognition. The measurements acquired, along with the National Eye Institute Visual Function Questionnaire 25 (VFQ 25) scores, were benchmarks against which change was measured after the patients received a program of vision therapy.
After 12 weeks of vision therapy treatment, the following skills showed statistically significant improvements:
• Near activities (p=0.001)
• Distance activities (p= 0.002)
• Social functioning (p=0.002)
• Mental health (p=0.0004)
• Role limitation, i.e., “I can’t do that” (p= 0.03)
• Dependency, i.e., “I need you to help me do that” (p=0.02).
We learned that while no two visual snow syndrome patients are exactly the same, there are common factors. Stress appears to play a role, with most patients feeling highly anxious. One question that arose was, which came first – the anxiety or the snow?
The effect of brain and body inflammation were also discussed at length. With the benefit of increased research over the past 10 years, a strong theory is that inflammation of microglial cells in the brain could contribute to the symptoms, as these cells swell and lose connectivity while they are in an activated state.
Listening to patients with visual snow syndrome and taking a detailed case history is step one in their management.
To rebuild their visual systems so they can deal with the visual demands of their world, these patients need to develop a foundation of good mental and physical health, diet, and sleep.
Eager For More
Our knowledge of visual snow remains limited, however with increasing interest in this syndrome, and studies underway, it’s clear that we will discover much more in the future.
For now, when I next encounter visual snow in my office, I will have an assessment and treatment plan ready to offer my patient.
Clare Campitelli, BSc Optom (University of Melbourne) is an optometrist and director of Vision on Koornang in Melbourne, and is a Fellow of ACBO.