Beyond Charles Bonnet Syndrome: A Scoping Review of Psychotic Symptoms in Vision Loss

Despite ongoing discussions regarding the connection between overt psychosis and the impairment of visual function, the discourse primarily centers on the potential neurobiological association between major psychotic disorders and congenital blindness. Specific neurological lesions are associated with psychotic symptoms, including visual hallucinations. Defining and assessing psychotic-like symptoms remains problematic and the negative effects of vision loss on the development of psychotic-like symptoms have not been adequately studied. In this scoping review, we present a clear picture of this complex relationship, with conclusions that will assist the differential diagnosis of psychotic symptoms in the ophthalmological patient. A literature search was undertaken on primary studies and reviews about psychotic symptoms in eye disease outside the context of the Charles Bonnet syndrome and established dementia. Seven reviews and nine primary studies or case series were included in the article. Nearly all reviews and two primary studies centered on visual hallucinations (VH) and only three primary studies expanded the scope to include other psychotic symptoms. There are considerable gaps in our knowledge concerning the characteristics of psychotic symptoms in patients with eye disease, primarily due to the lack of willingness to examine the possibility that a significant number of psychotic symptoms other than VH exist. Furthermore, the lack of a consensus on a set of criteria for Charles Bonnet syndrome is hampering research that would assist clinical management and the field, overall. A shift in the field of psychiatric research to the study of other psychotic symptoms, including non-hallucinatory changes to typical visual perception, has been noted but remains in the very early stages. Building on this new knowledge base with the addition of psychotic symptoms in newly established visual disorders, will help both fields.