Das Visual-Snow-Syndrom: Symptome und ophthalmologische Befunde

Abstract

The symptom "visual snow" describes the continuous perception of tiny flickering dots within the whole visual field of both eyes. The diagnosis of a visual snow syndrome requires the appearance of typical additional visual symptoms and the exclusion of ophthalmological or neurological causes, or pharmacological influences. Three male and four female subjects between 13 and 36 years of age referred with visual snow were investigated and asked about their symptoms. A complete ophthalmological investigation, including binocular fundoscopy, was performed in all patients. Furthermore, best corrected visual acuity, perimetry, binocular functions, colour vision (D15-test), full-field ERG, pattern-reversal VEP and SD-OCT images of macula and optic nerve (RNFL) were analysed. Visual acuity of at least 1.0 and normal findings for all further investigations were observed in all patients. The following additional visual symptoms were identified: illusionary palinopsia (n = 6), disturbance of night vision (n = 5), positive light phenomena (n = 7). A history of migraine with aura was reported in five patients. The intake of hallucinogenic drugs or centrally active pharmaceuticals was denied by all patients. The findings of available or initiated neurological investigations were normal. The visual snow syndrome has to be regarded as a diagnosis of exclusion. Visual function parameters are not impaired. Apart from eye diseases, a persistent migraine aura as well as neurological diseases or the intake of hallucinogenic drugs must be excluded as possible causes of visual snow and palinopsia.

Visual Snow Syndrome as a Network Disorder: A Systematic Review

“…Ophthalmological or radiological routine findings are without pathological findings in most cases ( 4 , 11 , 16 , 17 , 39 ). There are some case reports of patients with positive visual phenomena similar to those in VS, which turned out to be caused by ocular pathology, such as birdshot retinopathia ( 16 , 40 ), but also diseases leading to an extensive visual impairment like in a patient described by Mehta et al who had advanced macular atrophy with cystic retinal degeneration and developed Charles-Bonnet syndrome with VS in addition ( 16 ).…”

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

“…Unfortunately, the study by Yildiz et al It is understood that objective electrophysiological parameters would be extremely useful to assay benefits of treatment in visual snow. At present, results of electrophysiological studies seem to be differing [11][12][13]17,18 && ,25 && ] which might, however, partly be related to different examination protocols, for example, when assessing habituation. Larger studies are awaited to elucidate the field.…”

“…Irrespective of this semantic debate, visual snow syndrome criteria base on purely subjective descriptions of visual symptoms. Ophthalmic and neurological examination is typically normal [11], including perimetry [5,12,13,17], optical coherence tomography [17], electroretinography [11][12][13]17] as well as -until recently -visual evoked potentials (VEP) [11][12][13]17].…”

Das Visual-Snow-Syndrom in der augenärztlichen Praxis

“…Migräne, Epilepsie, zerebrale Läsionen) oder pharmakologische Ursachen. Als typische zusätzliche Symptome wurden in Fallstudien die illusionäre Palinopsie (84%), entoptische Phänomene (76%), Photophobie (72%), Störungen des Dämmerungssehens (63%) sowie positive Lichtphänomene beschrieben (53%) [2, 3].…”