Patients with so-called ‘visual snow’ describe a persistent disturbance in the entire visual field resembling the ‘static’ or ‘snow’ of a badly-tuned analogue television. The symptoms are continuous and can persist over years. Although many primary care providers, ophthalmologists, neuro-ophthalmologists and neurologists have seen patients with such complaints, the problem remains undefined."
Source : Brain, Volume 137, Issue 5, Pages 1419–1428
The cause of visual snow is unknown. It's often, but not always, associated with Migraineplugin-autotooltip__plain plugin-autotooltip_bigMigraine
"Chronic migraine has a great detrimental influence on a patient’s life, with a severe impact on socioeconomic functioning and quality of life. Chronic migraine affects 1–2% of the general population, and about 8% of patients with migraine; it usually develops from episodic migraine at an annual conversion rate of about 3%.", and with a variety of other visual disturbances - and also with the hearing disorder Tinnitusplugin-autotooltip__plain plugin-autotooltip_bigTinnitus
"Tinnitus is the perception of noises in the head and/or ear which have no external source. It derives from the Latin word for ringing and those living with the condition may have to endure a ringing, buzzing, hissing, whistling or other noise. The sensation can be constant or intermittent and it can vary in volume..
Current research suggests that the syndrome is not an eye problem as such, but appears to be a malfunction in the brain's visual system, specifically in the right lingual gyrus and the left cerebellar anterior lobe.
There are currently no successful treatments.
Further info : VisualSnowSyndrome.com