Vision impairment often comes as one enters more advanced years of life. The loss of vision can have a wide-ranging ripple effect: the ability to drive and read, through to loss of confidence in being able to manage the everyday tasks of life.
But what if something was added to your visual world that made you begin to question your own sanity?
This is the reality for 30 to 40 per cent of vision-impaired Australians who begin to 'see' imagery superimposed over their usual impoverished visual experience.
The imagery experienced can range from coloured blobs and geometric patterns to figures, buildings and even full landscapes. This condition is known as Charles Bonnet syndrome(CBS).
CBS is a fascinating perceptual disorder characterised by vivid phantom images being 'seen' by sane, vision-impaired people.
The person understands that what they 'see' is not real but are astonished at how detailed they appear.
The syndrome primarily affects people living with some form of eye disease (eg. macular degeneration, glaucoma, cataract) and an episode of the imagery can last seconds, minutes or even longer.
It was first clinically noted in 1760, but more than 260 year later, the syndrome continues to lurk in the clinical shadows. So why have so few heard of this condition if it affects so many people with vision loss?
Two factors have regrettably dovetailed to ensure CBS remains a hidden phenomenon. One is that medical and health care professionals are not screening for, or forewarning of, CBS with their patients.
The other is that patients are often so fearful of the implications of disclosing their unusual visual experiences that they tend to keep them a closely guarded secret. Some seriously question their sanity.
If clinical staff began to openly discuss CBS with their patients, it could allay much of the needless anxiety that patients endure. They could be reassured that CBS is not a mental illness nor a sign of cognitive or memory decline.
Rather, it is a curious side-effect of vision loss comparable to phantom limb syndrome: when a person loses a limb, they often later report experiencing sensations as if that lost limb was still there.
While there is no universal cure for CBS, there are various strategies that can be employed to reduce - or even sometimes resolve - the imagery.
This includes maximising one's remaining vision (for example, by reducing glare) and exploring fresh ways to relate to (and possibly challenge) the imagery.
For more information, visit www.charlesbonnetsyndrome.org or the helpline: 1300 121 123.
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