Visual snow syndrome: a review on diagnosis, pathophysiology, and treatment

Traber, Ghislaine L.; Piccirelli, Marco; Michels, Lars

doi:10.1097/wco.0000000000000768

Cited by 28 publications

(30 citation statements)

References 43 publications

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“…So far, disturbed processing of visual information downstream the primary visual cortex seems to be the most likely site of origin as outlined in a recent review article (Traber et al, 2020). Earlier work by Schankin et al (2014b) reported hypermetabolism (using PET) of the lingual gyrus and cerebellar anterior lobe in 17 patients with VS, already indicating disease-related effects allocated downstream of the primary visual cortex.…”

Section: Functional Alterationsmentioning

confidence: 96%

Abnormal Connectivity and Brain Structure in Patients With Visual Snow

Aldusary

Traber

Freund

et al. 2020

Front. Hum. Neurosci.

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Objective: Visual snow (VS) is a distressing, life-impacting condition with persistent visual phenomena. VS patients show cerebral hypermetabolism within the visual cortex, resulting in altered neuronal excitability. We hypothesized to see disease-dependent alterations in functional connectivity and gray matter volume (GMV) in regions associated with visual perception. Methods: Nineteen patients with VS and 16 sex-and age-matched controls were recruited. Functional magnetic resonance imaging (fMRI) was applied to examine resting-state functional connectivity (rsFC). Volume changes were assessed by means of voxel-based morphometry (VBM). Finally, we assessed associations between MRI indices and clinical parameters. Results: Patients with VS showed hyperconnectivity between extrastriate visual and inferior temporal brain regions and also between prefrontal and parietal (angular cortex) brain regions (p < 0.05, corrected for age and migraine occurrence). In addition, patients showed increased GMV in the right lingual gyrus (p < 0.05 corrected). Symptom duration positively correlated with GMV in both lingual gyri (p < 0.01 corrected). Conclusion: This study found VS to be associated with both functional and structural changes in the early and higher visual cortex, as well as the temporal cortex. These brain regions are involved in visual processing, memory, spatial attention, and cognitive control. We conclude that VS is not just confined to the visual system and that both functional and structural changes arise in VS patients, be it as an epiphenomenon or a direct contributor to the pathomechanism of VS. These in vivo neuroimaging biomarkers may hold potential as objective outcome measures of this so far purely subjective condition.

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Section: Functional Alterationsmentioning

confidence: 96%

Abnormal Connectivity and Brain Structure in Patients With Visual Snow

Aldusary

Traber

Freund

et al. 2020

Front. Hum. Neurosci.

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“…It generally lasts for months to years, and no underlying etiology is identified. This syndrome was first referred to as “visual snow phenomena” in 2005 ( 4 ) and later as VSS ( 5 ) with VS as the defining characteristic of the VSS, which includes other visual and perceptual symptoms ( 2 , 6 ). In 2014, Schankin et al proposed a definition of VSS to include two of the following: (1) palinopsia, (2) enhanced entopic phenomena (excessive floaters, excessive blue field entopic phenomena, self-light of the eye, or spontaneous photopsia), (3) photophobia, and (4) nyctalopia (night blindness).…”

Section: Discussionmentioning

confidence: 99%

Diagnostic Evaluation of Visual Snow

et al. 2021

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Introduction: To determine which patients with visual snow (VS) and VS syndrome (VSS) require standard ophthalmologic testing including automated visual field and which patients require further testing such as macular spectral domain optical coherence tomography (SD-OCT), electrophysiology, and neuroimaging.Materials and Methods: We retrospectively reviewed 52 consecutive patients at three institutions with VS and VSS including the University of Alabama, Callahan Eye Hospital, the University of Missouri-Kansas City School of Medicine, and the Little Rock Eye Clinic from the years 2015 to 2021. We collected historical information, examination findings, ophthalmic testing, electrophysiology, and neuroimaging.Results: Of the 52 patients with VS and VSS, eight of the 52 cases met the clinical criteria for VSS. The ages ranged from 7 to 79 years, with a mean age of 25 years (SD = 14.0). There were 22 males and 30 females. Color vision was tested in 51 cases and was normal in 47 cases (92%). A funduscopic exam was performed in all 52 cases and was normal in 46 cases (88%). The macular SD-OCT was normal in all of the 19 cases that it was performed (100%). A Humphrey visual field was performed in 50 cases and was normal in 43 (86%). A visually evoked potential (VEP) was normal in 18 of the 19 cases where it was obtained (95%). The full-field electroretinography (ffERG) was obtained in 28 cases and was normal in 25 (89%). The multifocal electroretinography (mfERG) was normal in 11 of 12 cases (92%). Only four patients accounted for all of the abnormal electrophysiological tests. In the 37 cases that had an MRI, 29 were normal (78%). Only one patient revealed a lesion in the visual pathway (right optic nerve enhancement in an optic neuritis patient).Conclusions: Patients with VS and VSS, if typical in presentation and with normal testing, do not require a workup beyond a thorough history, neuro-ophthalmologic examination, and automated perimetry. If this testing is abnormal, then ancillary testing is required.

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“…VSS is not notorious in its pathogenesis, although visual disturbances recur. The appearance and persistence of visual phenomena may psychologically disturb the patient [2,5,8]. This frightening condition prompts urgent referral to eye care professionals.…”

Section: Introductionmentioning

confidence: 99%

Visual snow: a neuro-ophthalmic syndrome

Albano¹,

Guerriero²,

Alessio³

2022

Med Hypothesis Discov Innov Optom

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Background: The visual snow syndrome (VSS) is a rare disease characterized by persistent positive visual phenomena that are enigmatic and may be underestimated. It manifests as the perception of tiny, simultaneous, diffuse, and mobile dots frequently throughout the visual field. Although it affects brain networks, ocular examination is also indicated. This paper was aimed to review recent studies on VSS to identify the best clinical approach. Methods: In this narrative review, PubMed/Medline, Directory of Open Access Journals, and Embase were searched using the following terms: “Visual snow”, “Persistent aura”, “Persistent positive visual phenomena”, “Visual aura”, “Migraine”, “TV static”, “Migraine aura status”, and “Visual disturbance”. We searched relevant publications from January 2014 to January 2021 to find the best clinical approach. Results: VSS may be reconstituted as a distinct entity, although the symptoms may be consistent with typical migraine visual aura. For approximately two-thirds of patients, symptoms worsen and reduce their ability for activities of daily living. It often causes psychogenic detriment of the patient and their capacity to function socially and vocationally. Comprehensive history-taking and ocular examination are required to rule out other causes. However, all ocular and radiological findings may be normal. Conclusions: VSS is a neuro-ophthalmic disorder characterized by continuous chronic and recurrent visual disturbances that involve the entire visual field and may respond to empiric antimigraine or anti-seizure treatments. It may reduce the ability for activities of daily living; therefore, proper diagnosis by eye care professionals is necessary to determine its diagnosis and management.

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Visual snow syndrome: a review on diagnosis, pathophysiology, and treatment

Cited by 28 publications

References 43 publications

Abnormal Connectivity and Brain Structure in Patients With Visual Snow

Abnormal Connectivity and Brain Structure in Patients With Visual Snow

Diagnostic Evaluation of Visual Snow

Visual snow: a neuro-ophthalmic syndrome

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