Agony of the patients with ‘eye tinnitus’

THOUSANDS of patients who suffer headaches may in fact have a new, previously unrecognised vision problem dubbed ‘tinnitus for the eyes’. The distressing symptoms can persist for years, but until now patients have been told they are the result of a wide range of other conditions, including migraine.

Researchers call the condition visual snow disorder, as sufferers often say they ‘see’ through a fog that resembles the static of a badly tuned oldfashioned television.

Although many GPs, ophthalmologists and neurologists have patients with visual snow, it has not been seen as a stand-alone disorder.

A new study was based on an analysis of patients reporting visual snow at a number of centres, including the National Hospital for Neurology and Neurosurgery in London.

About 250 patients were included in the study, reported in the journal Brain. Researchers interviewed people in 11 European countries, as well as the United States and Australia.

The average age of patients was 30, and they had suffered visual snow for an average of nine years. One in four had been affected for as long as they could remember.

Participants had additional symptoms in common including difficulty in seeing at night and still seeing an object after it had disappeared from view. Headaches were also common, hence the misdiagnosis.

Some patients had been diagnosed with psychiatric problems, or were said to be suffering from a drug- induced ‘flashback’. It now seems that diagnosis was incorrect.

Researchers say the high prevalence of additional symptoms indicates that patients with visual snow have a real and unique syndrome. That is backed up by the presence of the symptoms in childhood and adolescence, and poor responses to conventional treatments, they add.

Curiously, it was discovered that patients had an increased risk of tinnitus, the perception of phantom sounds, typically a ringing in the ears. That, it is suggested, supports the idea that visual snow is a disorder of the brain rather than the eyes.

‘Visual snow might be for the visual system what tinnitus is for the auditory system,’ say researchers. They believe that making it a separate condition will lead to more research, a better understanding of the causes, and to specific treatments.

Dr Nicholas Silver, consultant neurologist at The Walton Centre NHS Trust in Liverpool, said: ‘This study has investigated a phenomenon that is widely reported in neurology and ophthalmology clinics.

‘The reported presence of persistent visual disturbances is often highly distressing to patients, particularly when symptoms are invisible to outsiders, and their doctors question whether these are genuine or psychological complaints.

‘Hopefully this study will lead to a greater understanding of the mechanisms of this distinct entity to allow more focused treatments.’