BLOG: Shining a light on visual snow
Click Here to Manage Email Alerts
Visual snow syndrome is a fascinating phenomenon of unknown neurological etiology. Although many clinicians have never even heard of it or consider it rare, my experience suggests it is more common than previously thought.
Visual snow syndrome (VSS) includes both visual and nonvisual symptoms. The nonvisual symptoms may include tremor, for example. The primary visual symptom is a perception of what patients describe as snow, pixelated vision, fuzz, bubbles or TV static in the foreground of their visual field. One patient described it as similar to looking through a cracked iPhone screen.
Two recent papers include representative images that can help clinicians understand what their patients see with VSS (Ciuffreda et al., Schankin et al.). Patients may also describe palinopsia and other visual symptoms. All together, these symptoms can range from mildly to extremely debilitating.
Some patients develop VSS idiopathically and have adapted to it as a permanent condition. In fact, they may not even realize that not everyone sees the world the way they do. When VSS is described to students in a large class, a few will say they see visual snow but never knew it was called that. Others develop suddenonset VSS following a traumatic brain injury, in response to a viral infection or even from optic nerve damage. VSS has been associated with several other neurological conditions, including migraine, tinnitus, cutaneous allodynia and hypersensitivity to light or sound.
I have learned that many patients (especially children) don’t have the vocabulary to describe VSS — or may describe something that sounds so bizarre that their parents or doctors think they simply have an overactive imagination. When patients seem to have very vague but bothersome symptoms, I ask them specifically if they see something that looks like snow or static in their vision or show them a picture another patient drew of their visual snow. We have developed a questionnaire for clinical use that covers many of the associated findings and conditions (Ciuffreda et al.).
Interestingly, lens tints can significantly reduce the perception of visual snow. One young patient of mine who had undergone removal of a cyst in her brain discovered by accident when trying on sunglasses at the mall that rosetinted lenses reduced her symptoms. Since then, I have explored this much further. It turns out that different patients require different colors but for many, a tint can reduce the visual snow symptoms by up to 70%. Tints will not help optic nerve damage patients and may have less impact on those with longstanding VSS.
We use a colorimeter and a process much like refraction to find the precise color that will benefit an individual patient the most. It is quite amazing to see the patient’s whole face change when you find the right color. They just immediately relax and say, “Wow, that’s so much better!”
References:
- Ciuffreda KJ, et al. Vis Dev & Rehab. 2019;doi:10.31707/VDR2019.5.2.p75.
- Schankin CJ, et al. Brain. 2014;doi:10.1093/brain/awu050.
For more information:
M.H. Esther Han, OD, FCOVD, FAAO, DiplABO, specializes in neurooptometric rehabilitation. She is a fulltime associate clinical professor at the SUNY College of Optometry and the residency program supervisor for the neurooptometric rehabilitation residency there. Han has been a member of the COVD International Exam and Certification Board since 2014 and a board member for the Eastern States Optometric Congress since 2013.
Han will be presenting a talk at the NORA virtual annual conference, Sept. 1213, 2020, on the management of patients with VSS. For more information on the conference, please visit www.nora2020.com.
Disclaimer: The views and opinions expressed in this blog are those of the authors and do not necessarily reflect the official policy or position of the Neuro-Optometric Rehabilitation Association unless otherwise noted. This blog is for informational purposes only and is not a substitute for the professional medical advice of a physician. NORA does not recommend or endorse any specific tests, physicians, products or procedures. For more on our website and online content, click here.
Collapse