Charles Bonnet Syndrome associated with unilateral vision loss: A new diagnostic perspective

To increase recognition of Charles Bonnet Syndrome (CBS) beyond its conventional association with 'significant vision loss', which is indicated in the current literature as a diagnostic criterion.

Clinical observation of CBS associated with unilateral visual loss following enucleation due to choroidal melanoma. Comprehensive visual assessments were performed. The cognitive function was assessed with the Montreal Cognitive Assessment (MoCA)-BLIND. The phenomenology, occurrence and impact of visual hallucinations were evaluated using the University of Miami Parkinson's Disease Hallucinations Questionnaire (UM-PDHQ). A critical literature review of CBS cases associated with vision loss in one eye only was conducted.

In this case and in an additional nine reported cases in the literature, CBS hallucinations occurred following unilateral vision loss despite preserved visual function in the fellow eye. These hallucinations are phenomenologically consistent with those observed after severe bilateral vision loss, indicating that both conditions can lead to the development of CBS.

CBS should be screened in all patients who have experienced any degree of vision loss.