Charles-Bonnet syndrome occurs in patients with loss of vision (usually due to ocular pathology) who experience visual hallucinations.
Although numerous causes are seen (any cause of gradual ocular visual failure can theoretically produce Charles Bonnet syndrome, as can other locations for visual loss e.g. optic chiasm, radiation and occipital lobes) the most common cause is macular degeneration 1; representing how prevalent this condition is. Not surprisingly, therefore, elderly patients are most commonly affected 1.
Patients typically experience hallucinations when awake with eyes open, typically in the evenings or at night 1. The hallucinations themselves are not stereotyped (i.e. they vary from day to day), and patients have insight into the fact that these are not real, and tend not to be distressed by them 1.
Imaging of the brain is two-fold. Firstly, in patients with ocular pathology, to exclude other causes of visual hallucinations (e.g. peduncular hallucinosis, Lewy body dementia etc). In those without ocular pathology, a lesion along the optic tracts/occipital cortex should be sought.