Hallucinations linked to vision loss from macular degeneration are caused by abnormally heightened activity in the visual cortex of the brain, according to new Australian research.
That means they are nothing to particularly worry about and do not need special treatment.
Macular degeneration causes progressive deterioration of the central region of the retina, affecting the centre of the field of vision but not peripheral vision.
Many people with this condition also develop Charles Bonnet Syndrome(CBS), in which they experience hallucinations as the brain adjusts to the significant vision loss. These range from flashes of light or simple shapes to complex visions of people, animals or entire scenes.
To test a theory that this is linked to “excitability” in the brain, a team from the Queensland Brain Institute at the University of Queensland stimulated the peripheral visual fields of study participants and found that those who suffered hallucinations showed significantly heightened activity in parts of their visual system.
They don’t yet know how or why, but they know it occurs, and straight away that could help reduce misdiagnosis.
“Once people realise it’s not a brain disorder as such, they tend to have a neutral or even positive experience of their hallucinations. Unlike the hallucinations in people with schizophrenia, for example, individuals with Charles Bonnet Syndrome are aware their hallucinations aren’t real,” [said author David Painter.]
Read full, original post: Potential mechanism for retina-linked hallucinations discovered