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Purpose: Complex visual hallucinations are rarely seen in neurooncology. They are commonly observed alongside psychotic symptoms in schizophrenia or dementia, in Parkinson's or Lewy-body disease, after opioid medications or anesthesia, and, in particular, they appear with visual impairments., Methods: Here we report two normal-sighted and mentally healthy patients with unusual visual hallucinations after the resection and irradiation of brain metastases, the main features of which were persistent colorful and meaningful images with hallucinatory perseveration., Results: These cases demonstrate the occurrence of complex visual hallucinations after resection of visual cortices as an effect of deafferentation, so-called visual release hallucinations or phantom images, similar to phantom pain after amputation of a limb., Conclusion: This case serves to heighten awareness in the radiooncology practitioner of the occurrence of visual release hallucinations (Charles Bonnet syndrome) related to multidisciplinary treatment of brain metastases., (© 2024. The Author(s).)

Complex visual hallucinations can occur in visually impaired individuals with no underlying psychiatric disorder. This phenomenon is known as Charles Bonnet syndrome (CBS). It is more common in elderly patients who are suffering from impaired vision due to ocular or neurological disease processes, resulting in sensory deprivation. We report a case of CBS in an elderly female with marked ptosis, which was exacerbated following a knee replacement surgery under general anaesthesia. Her CBS symptoms persisted until surgical correction of the ptosis, with a rapid and dramatic resolution of her hallucinations. Although CBS is typically a chronic condition, unusually in this case it was acute and reversible.

Throughout the lifespan, the cerebral cortex adapts its structure and function in response to changing sensory input [1, 2]. Whilst such changes are typically adaptive, they can be maladaptive when they follow damage to the peripheral nervous system, including phantom limb pain and tinnitus [3, 4]. An intriguing example occurs in individuals with acquired ocular pathologies-most commonly age-related macular degeneration (MD) [5]-who lose their foveal vision but retain intact acuity in the peripheral visual field. Up to 40% of ocular pathology patients develop long-term hallucinations involving flashes of light, shapes, or geometric patterns and/or complex hallucinations, including faces, animals, or entire scenes, a condition known as Charles Bonnet Syndrome (CBS) [6, 7, 8]. Though CBS was first described over 250 years ago [9, 10], the neural basis for the hallucinations remains unclear, with no satisfactory explanation as to why some individuals develop hallucinations, while many do not. An influential but untested hypothesis for the visual hallucinations in CBS is that retinal deafferentation causes hyperexcitability in early visual cortex. To assess this, we investigated electrophysiological responses to peripheral visual field stimulation in MD patients with and without hallucinations and in matched controls without ocular pathology. Participants performed a concurrent attention task within intact portions of their peripheral visual field, while ignoring flickering checkerboards that drove periodic electrophysiological responses. CBS individuals showed strikingly elevated visual cortical responses to peripheral field stimulation compared with patients without hallucinations and controls, providing direct support for the hypothesis of visual cortical hyperexcitability in CBS., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Charles Bonnet Syndrome describes the triad of complex visual hallucinations secondary to ophthalmic pathology in psychologically normal people. We present a rare case of acute-onset Charles Bonnet Syndrome following cardiac surgery that resulted in profound loss of visual acuity in both eyes with characteristic visual hallucinations that were initially mistaken for delirium. Computed tomography of the brain revealed bilateral occipital infarcts, providing the substrate for Charles Bonnet Syndrome. A high index of suspicion should be maintained in cognitively intact patients with visual loss who are also experiencing visual hallucinations to ensure prompt diagnosis and management of this often overlooked condition.

Introduction: Charles Bonnet syndrome (CBS) is a condition that causes visual hallucinations in patients without any mental illnesses. CBS is characterized by the presence of vivid, complex and recurrent visual hallucinations, and do not occur in the setting or as part of delirium or other psychological illnesses. The condition is present in patients who have visual loss due to age-related macular degeneration (AMD), cataracts and/or other ocular diseases that influence vision., Case Report: A 81-year-od woman reported to ophthalmologist complaining of visual hallucinations that consisted of white pigeons. Hallucinations were present for two years and she was well aware that hallucinations were unreal. Mental illnesses were excluded by the psychiatrist. Complete ophthalmologic examination was performed, and finding revealed visual acuity of 0.3 (right eye) and 0.5 (left eye), in both eyes cataracts and AMD (wet form). Optical coherence tomography confirmed the fundoscopic finding of AMD. The patient rejected treatment of cataracts and AMD due to old age, and hallucinations persisted., Conclusion: CBS should be considered in patients with visual hallucinations and ocular diseases that influence vision. It is essential to distinguish CBS from mental illnesses, since patients with CBS are fully aware that hallucinations are not real. Awareness of CBS could help physicians upon referring patients to ophthalmologists instead of psychiatrists, and therefore avoid patients being misdiagnosed.

Charles Bonnet syndrome is a condition manifesting as visual hallucinations associated with vision impairment in patients without the underlying n euro psychiatric pathologies. As the incidence of age-related macular degeneration is on the rise, we can anticipate increasingly frequent cases of Charles Bonnet syndrome in our patients. The aim of the paper is to present a case of a 75-year-old patient who developed visual hallucinations secondarily to severe bilateral vision impairment due to exudative age-related macular degeneration. Patients with advanced age-related macular degeneration and no history of neuropsychiatric disorders may present with visual hallucinations.