Objective: To investigate whether sensory sensitivity is associated with the perceived severity of Visual Snow Syndrome (VSS) symptoms.Background: Visual Snow (VS) is a perceptual anomaly which manifests as flashing pinpricks of light throughout the visual field. VSS has an estimated population prevalence of 2.2% and is thought to be at least moderately debilitating for all who experience it. However, some people who meet the criteria for VSS have no awareness of it. This may be because they have lower sensory sensitivity, allowing them to ignore their visual phenomena. Method:Our study used a cross-sectional design. We recruited two distinct samples of people with VSS: a sample of people with confirmed VSS; and a sample of people who met the criteria for the condition but had no prior knowledge of it (latent VSS). The latter group was recruited and screened for symptoms via an online crowdsourcing platform. In total, 100 participants with VSS (49 with confirmed VSS, 51 with latent VSS) completed the Visual Snow Handicap Index and three measures of sensory hypersensitivity. Results:The 100 participants (52 female, 47 male, 1 non-binary) had a mean age of 35.1 years (SD = 12.2). Leiden Visual Sensitivity Scale scores were associated with both the perceived severity of VSS, β = 0.35, p = 0.003, and the number of VSS symptoms endorsed, β = 0.45, p < 0.001. On average, participants with VSS experienced elevated sensory hypersensitivity across all measures. Furthermore, longer duration of VSS was associated with lower perceived severity, F(1, 98) = 11.37, p = 0.001, R 2 = 0.103. Conclusions: Our results suggest that sensory hypersensitivity may be prevalent in people with VSS and indicate that visual allodynia is associated with increased severity of VSS. Additionally, our findings indicate that inclusion of cases of latent VSS in | 495 H EAD ACH E INTRODUC TI ON Visual Snow (VS) is a perceptual anomaly which manifests as flashing pinpricks of light (dynamic noise) throughout the visual field. 1 It is the key symptom of Visual Snow Syndrome (VSS); but VSS is also associated with other visual, auditory, and neurological phenomena, including palinopsia, enhanced entoptic phenomena, photophobia, and nyctalopia. 2 Figure 1 simulates the experience of VS, compared to normal vision.Between 5% and 50% of people with VSS have had the condition for as long as they can remember. 3,4 Many people who acquire VSS later in life can identify a specific preceding event, such as acquired brain injury, first-instance use of medication, or viral infection. 5,6 Research suggests that VSS impacts daily life, with challenges ranging from difficulty engaging with work due to struggles with computer screens, to inability to drive, especially at night. 7 However, anecdotal evidence from online VSS discussion groups, and recent quantitative evidence, suggests some people with VSS do not always find it debilitating. 7 Furthermore, people with lifelong VSS rate their perceptual phenomena as less debilitating and rate health-related quality of li...

Visual Snow (VS) is a perceptual anomaly which manifests as flashing pinpricks of light (dynamic noise) throughout the visual field. Visual Snow Syndrome (VSS) has an estimated population prevalence of 2.2% and is thought to be at least moderately debilitating for all who experience it. However, some people who meet the criteria for VSS seemingly have no awareness of it. This may be because they have lower sensory sensitivity, allowing them to ignore these visual phenomena. To investigate this, we recruited two distinct samples of people with VSS: a sample of people with confirmed VSS, recruited via online communities associated with the condition; and a sample of people who met the criteria for the condition but had no prior knowledge of it, recruited and screened for VSS via a crowd-sourcing platform. In total, 100 participants with VSS (49 with confirmed VSS, 51 with latent VSS) completed the Visual Snow Handicap Index and three measures of sensory hypersensitivity. Photophobia predicted both the perceived severity of VSS (β = .35) and the number of VSS symptoms endorsed (β = .45). On average, participants with VSS experienced elevated sensory hypersensitivity across all measures. Additional analyses showed that participants who knew they had VSS endorsed significantly more symptoms than those who did not (p &lt;.001). Furthermore, longer duration of VSS was associated with lower perceived severity (p = .001). Our results suggest that sensory hypersensitivity may be prevalent in people diagnosed with VSS, and indicate that inclusion of cases of latent VSS in future research may be important for a complete understanding of VSS.