Materiały źródłowe

• #1 Charles Bonnet Syndrome – StatPearls – NCBI BookshelfTwitterFacebookLinkedInGitHubNCBI Insights BlogTwitterFacebookYoutube

  https://www.ncbi.nlm.nih.gov/books/NBK585133/

  Charles Bonnet syndrome (CBS) is a phenomenon characterized by complex visual hallucinations in visually challenged patients but otherwise psychologically normal. […] CBS can manifest when there is a lesion at any level of the visual system, and typically patients manifest with a loss of central visual acuity. CBS is also associated with ARMD with a secondary decline in visual acuity. […] The current and most commonly accepted theory for the visual hallucinations seen in CBS is that visual sensory deafferentation results in disinhibitions of cortical regions affecting vision. […] Ultimately, this disinhibition leads to spontaneous firing of these vision-associated regions, resulting in hallucinations. […] The proposed theory for CBS is the phantom limb pain theory. Phantom limb pain theory explains a feeling of pain even when the limb has been removed. The patient feels pain even though the limb has been removed. Similarly, patients with CBS may have visual sensations despite being unable to see them. […] The pathophysiology of CBS first starts with any factor that leads to loss of vision. These factors which can affect any part of the visual pathway commonly include cataracts, glaucoma, diabetic retinopathy, age-related macular degeneration, and cerebral infarction affecting the visual cortex.

• #2 Charles Bonnet Syndrome – EyeWiki

  https://eyewiki.org/Charles_Bonnet_Syndrome

  Charles Bonnet Syndrome (CBS), named after the Swiss scientist who first described visual hallucinations in his grandfather in the 1970s, has three features: hallucinations, ocular pathology, and intact cognition. […] Deficits in any part of the visual pathway can cause CBS, yet the underlying mechanism of the hallucinations is unknown. Several theories have been proposed including phantom limb in the context of vision, reduced sensory input, perceptual release, and deafferentation. The theory of reduced sensory input is underpinned by the idea that dreams and hallucinations exist on the same continuum; reduced sensory input results in a state similar to sleep, causing the brain to create images. Reduced sensory input is somewhat related mechanistically to the theory of perceptual release, which suggests that normally filtered visual information is allowed to enter consciousness as a result of decreased visual input.

• #3 Charles Bonnet syndrome: a condition of the visually impaired – Dhooge – Annals of Eye Science

  https://aes.amegroups.org/article/view/6863/html

  In the 2018 revision of the International Classification of Diseases, the WHO has allocated a specific diagnose code for CBS. […] Based on this WHO definition, the principal diagnostic criteria include: (I) the presence of complex visual hallucinations; (II) partial or complete loss of vision; (III) the absence of mental or behavioural disorders.

• #4 Charles Bonnet Syndrome – StatPearls – NCBI BookshelfTwitterFacebookLinkedInGitHubNCBI Insights BlogTwitterFacebookYoutube

  https://www.ncbi.nlm.nih.gov/books/NBK585133/

  Charles Bonnet syndrome (CBS) is a phenomenon characterized by complex visual hallucinations in visually challenged patients but otherwise psychologically normal. […] CBS can manifest when there is a lesion at any level of the visual system, and typically patients manifest with a loss of central visual acuity. CBS is also associated with ARMD with a secondary decline in visual acuity. […] The current and most commonly accepted theory for the visual hallucinations seen in CBS is that visual sensory deafferentation results in disinhibitions of cortical regions affecting vision. […] Ultimately, this disinhibition leads to spontaneous firing of these vision-associated regions, resulting in hallucinations. […] The proposed theory for CBS is the phantom limb pain theory. Phantom limb pain theory explains a feeling of pain even when the limb has been removed. The patient feels pain even though the limb has been removed. Similarly, patients with CBS may have visual sensations despite being unable to see them. […] The pathophysiology of CBS first starts with any factor that leads to loss of vision. These factors which can affect any part of the visual pathway commonly include cataracts, glaucoma, diabetic retinopathy, age-related macular degeneration, and cerebral infarction affecting the visual cortex.

• #5 EyeRounds.org: Charles Bonnet Syndrome

  http://eyerounds.org/cases/302-Charles_Bonnet.htm

  Charles Bonnet Syndrome is relatively common, with an estimated prevalence of 10-40% in visually impaired patients. The visual hallucinations in CBS have been described with conditions of visual loss affecting any part of the visual system, including the eye, optic nerve, and brain, and may occur in almost any acquired disorder of the visual system. […] Visual hallucinations in the setting of CBS have a variety of manifestations. Some patients report simple images, such as lines, flashes of light, or patterns. Other patients may experience more complex visual hallucinations such as those of animals or people. […] One of the most important distinguishing features of visual hallucinations secondary to CBS is that the patient generally has insight into their condition and knows that the images are not real. Another characteristic of hallucinations unique to CBS includes that they predominately occur when the eyes are open, and tend to resolve when a patient closes their eyes or looks away. […] One study found that the hallucinations tend to be more prevalent in the setting of sensory deprivation, such as in low light situations, in social isolation, and general inactivity.

• #6 Charles Bonnet Syndrome (CBS) – Gene Vision

  https://gene.vision/charles-bonnet-syndrome-cbs/

  Charles Bonnet Syndrome (CBS) is characterised by visual hallucinations in people affected by sight loss from any cause, including inherited eye disorders. […] CBS is estimated to affect 0.4-30% of people with sight loss, though it is considered to be underreported due to patients’ fears of being categorised as mentally ill, and a relative lack of awareness amongst the medical profession. […] If the retina or any part of this pathway is damaged, the stream of electrical impulses to the visual cortex is reduced. It is believed that in CBS, the brain cells in the visual cortex responds paradoxically by firing more signals, causing visual hallucinations. […] The image of the hallucination depends on which area of visual cortex is stimulated. For example, a stimulation in an area specialised for faces will cause the hallucination to have faces.

• #7 The elephant in the room: understanding the pathogenesis of Charles Bonnet syndrome – PubMed

  https://pubmed.ncbi.nlm.nih.gov/31591762/

  Charles Bonnet syndrome (CBS) is a syndrome characterised by complex visual hallucinations in individuals who are cognitively normal, though often elderly and visually impaired. […] Our understanding of CBS pathogenesis has advanced little since it was first described, and much of the recent literature consists of case studies strikingly similar to the first published account of CBS. However, imaging studies have provided some indication as to the cortical areas implicated in the genesis of complex visual hallucinations, and the existence of similar hallucinatory syndromes in other sensory modalities suggests a common underlying mechanism. […] This review begins by describing what is currently known about CBS, focusing on epidemiology, clinical presentation and diagnosis. It then explores potential starting points for better understanding the pathogenesis of CBS, namely the existence of similar conditions in other sensory modalities and the reproduction of complex visual hallucinations in sensory deprivation scenarios.

• #8 Charles Bonnet Syndrome – EyeWiki

  https://eyewiki.org/Charles_Bonnet_Syndrome

  The most commonly accepted theory is deafferentation. In this context, deafferentation refers to the loss of afferent neurons responsible for vision transduction. This typically is due to a lesion in the visual pathway, which is always seen in CBS. The loss of the afferent fibers results in aberrant hyperexcitability in the visual cortex and can be attributed to a host of factors, including an increase in presynaptic release of neurotransmitters, an increase in the number of postsynaptic receptors, and a decrease in inhibitory neurotransmitter release; these changes give rise to visual hallucinations.

• #9 Charles Bonnet Syndrome: Complete Remission of Visual Hallucinations with Trazodone

  https://www.jneuropsychiatry.org/peer-review/charles-bonnet-syndrome-complete-remission-of-visual-hallucinations-with-trazodone-12999.html

  Charles Bonnet syndrome (CBS) is a neuro-ophthalmic condition that affects elderly people with visual impairment related to ophthalmological pathologies. […] Its mechanism involves spontaneous neuronal discharges of the visual cortex secondary to deafferentation of visual input. […] The etiology of CBS involves deafferentation of the visual system that leads to spontaneous neuronal discharges and consequently abnormal sensory perceptions. […] In CBS, spontaneous and/or stimulus-driven hyperexcitability of unimodal associative visual cortex underlies hallucinatory phenomena. […] The reason why only some individuals develop such hallucinations might be related to specific wiring conformation and/or presynaptic neurotransmitters concentrations and/or pre/post synaptic receptor avidities and densities. […] Trazodone is reported to block neuroplasticity through its 5-HT2C receptor antagonism, and perhaps the same “monoaminergic” effect could explain its efficacy in treating visual hallucinations.

• #10 Charles Bonnet Syndrome – Neuropedia

  https://neuropedia.net/articles/neurology/neuro-ophthalmology/charles-bonnet-syndrome/

  Charles Bonnet syndrome is a visual hallucination caused by the brain adapting to significant vision loss. […] Charles Bonnet Syndrome (CBS), also called phantom vision, is an illness where cognitively normal people experience simple or complex and consistent visual hallucinations, due to damage along the visual pathway. […] CBS can be caused by any factor affecting the visual pathway, extending from the visual cortex down to the eyes. […] The precise pathogenesis of CBS is still unknown. However, 2 main theories are suggested to explain the visual hallucinations experienced during CBS: The deprivation theory suggests that diminution in sensory input leads to the production of spontaneous images from the visual association cortex, resulting in visual hallucinations. […] The release theory suggests that a lesion of the visual pathway causes abnormal signals to be sent to the visual cortex. The hallucinations result from a combination of normal and abnormal signals at the level of the visual association cortex.

• #11 Charles Bonnet Syndrome – EyeWiki

  https://eyewiki.org/Charles_Bonnet_Syndrome

  The most commonly accepted theory is deafferentation. In this context, deafferentation refers to the loss of afferent neurons responsible for vision transduction. This typically is due to a lesion in the visual pathway, which is always seen in CBS. The loss of the afferent fibers results in aberrant hyperexcitability in the visual cortex and can be attributed to a host of factors, including an increase in presynaptic release of neurotransmitters, an increase in the number of postsynaptic receptors, and a decrease in inhibitory neurotransmitter release; these changes give rise to visual hallucinations.

• #12 Visual hallucinations in blindness | MedLink Neurology

  https://www.medlink.com/articles/visual-hallucinations-in-blindness

  Bonnet hallucinations are thought to result from a „release” mechanism associated with modality-specific sensory deprivation, ie, „phantom vision” akin to phantom limbs in patients with loss of somatosensory input after an amputation. […] The complex nature of Bonnet hallucinations indicates that they are generated in the visual association cortex. […] In support of a release mechanism for Bonnet hallucinations, sensory deprivation and a low level of arousal favor development of the hallucinations but are not required for their development. […] The specific pathophysiological mechanisms involved in Bonnet syndrome are still being investigated, but many authors have suggested a „release” mechanism associated with modality-specific sensory deprivation or deafferentation. […] Deafferentation produces an increase in excitability of the deafferentated neurons and an increase in spontaneous activity.

• #13 Charles Bonnet Syndrome Precipitated by Brimonidine Tartrate – The Journal of Medical Optometry (JoMO)

  https://journalofmedicaloptometry.com/volume2-issue1/charles-bonnet-syndrome-precipitated-by-brimonidine-tartrate/

  Charles Bonnet Syndrome (CBS) is a condition characterized by visual hallucinations in patients with vision loss and clear cognition. […] The pathophysiology of CBS starts with any eye disease that leads to vision loss. These conditions can include cataracts, glaucoma, diabetic retinopathy, age-related macular degeneration, or cerebral infarction affecting the visual cortex. […] The true mechanism of visual hallucinations that occur in CBS has not been established. The most popular theory is the deafferentation theory, also known as the sensory deprivation theory. The theory hypothesizes that reduced visual acuity or visual field defects decreases input to the visual cortex, which increases spontaneous neuronal discharge to the visual cortex. […] Functional MRI (fMRI) studies have supported the deafferentation theory by confirming the visual cortex activation that results in visual hallucinations in visually impaired patients.

• #14 Who is the Mystery Man? Charles Bonnet Syndrome in the Setting of Age-Related Macular Degeneration

  https://www.heraldopenaccess.us/openaccess/who-is-the-mystery-man-charles-bonnet-syndrome-in-the-setting-of-age-related-macular-degeneration

  The content of the hallucinations was associated with specific regional activation that correlated with the known specialized function of that area of the visual cortex. […] The duration of the hallucination ranges from less than one minute to continuous. […] The frequency is variable; most patients experience hallucinations multiple times a day or week. […] Patients with CBS typically do not have an abnormal mental status or other neurologic deficits. […] The differential diagnosis of visual hallucinations include migraine aura, epilepsy, neurodegenerative disease, especially dementia with Lewy bodies and Parkinson disease, drugs, alcohol intoxication or withdrawal, metabolic encephalopathy, delirium, peduncular hallucinosis, narcolepsy and psychiatric disease. […] In the absence of other neurologic abnormalities, and in the setting of known ocular disease (macular degeneration), further diagnostic evaluation may not be required.

• #15 Charles Bonnet Syndrome – Neuropedia

  https://neuropedia.net/articles/neurology/neuro-ophthalmology/charles-bonnet-syndrome/

  Charles Bonnet syndrome is a visual hallucination caused by the brain adapting to significant vision loss. […] Charles Bonnet Syndrome (CBS), also called phantom vision, is an illness where cognitively normal people experience simple or complex and consistent visual hallucinations, due to damage along the visual pathway. […] CBS can be caused by any factor affecting the visual pathway, extending from the visual cortex down to the eyes. […] The precise pathogenesis of CBS is still unknown. However, 2 main theories are suggested to explain the visual hallucinations experienced during CBS: The deprivation theory suggests that diminution in sensory input leads to the production of spontaneous images from the visual association cortex, resulting in visual hallucinations. […] The release theory suggests that a lesion of the visual pathway causes abnormal signals to be sent to the visual cortex. The hallucinations result from a combination of normal and abnormal signals at the level of the visual association cortex.

• #16 Visual release hallucinations (Charles Bonnet syndrome) – UpToDate

  https://www.uptodate.com/contents/visual-release-hallucinations-charles-bonnet-syndrome/print

  The Charles Bonnet syndrome (CBS) refers to symptoms of visual hallucinations that occur in patients with visual acuity loss or visual field loss. These are often called release hallucinations, reflecting the most widely accepted theory of their pathogenesis. […] Underlying conditions of vision loss associated with the CBS affect the eye, optic nerve, or brain and include a diverse set of pathologies, such as macular degeneration and stroke. […] The pathophysiology, causes, clinical features, diagnosis, and treatment of the CBS will be reviewed here.

• #17 Charles Bonnet Syndrome – StatPearls – NCBI BookshelfTwitterFacebookLinkedInGitHubNCBI Insights BlogTwitterFacebookYoutube

  https://www.ncbi.nlm.nih.gov/books/NBK585133/

  Charles Bonnet syndrome (CBS) is a phenomenon characterized by complex visual hallucinations in visually challenged patients but otherwise psychologically normal. […] CBS can manifest when there is a lesion at any level of the visual system, and typically patients manifest with a loss of central visual acuity. CBS is also associated with ARMD with a secondary decline in visual acuity. […] The current and most commonly accepted theory for the visual hallucinations seen in CBS is that visual sensory deafferentation results in disinhibitions of cortical regions affecting vision. […] Ultimately, this disinhibition leads to spontaneous firing of these vision-associated regions, resulting in hallucinations. […] The proposed theory for CBS is the phantom limb pain theory. Phantom limb pain theory explains a feeling of pain even when the limb has been removed. The patient feels pain even though the limb has been removed. Similarly, patients with CBS may have visual sensations despite being unable to see them. […] The pathophysiology of CBS first starts with any factor that leads to loss of vision. These factors which can affect any part of the visual pathway commonly include cataracts, glaucoma, diabetic retinopathy, age-related macular degeneration, and cerebral infarction affecting the visual cortex.

• #18 Charles Bonnet Syndrome | Low Vision Center At Mascoutah Eye CareOpen MenuClose MenuOpen MenuClose Menu

  https://www.mascoutaheyecare.com/eye-care-services/low-vision-optometrist/low-vision-eye-diseases/charles-bonnet-syndrome/

  Charles Bonnet Syndrome is caused by the way the brain reacts to vision loss. It begins in the weeks and months following a dramatic deterioration of sight. […] However, in those with vision impairment, the brain doesn’t receive as much information from the eyes as it used to, leading the brain to fill these gaps by creating new illusionary images. […] This condition is often compared to “phantom limb” experiences felt by people who have had a limb amputated. They may still feel their missing toes or fingers or may experience itching on an arm that is no longer there. This occurs when the nerves in the body are still active and send signals to the brain, leading the brain to interpret the signals as sensations coming from the missing limb. Similarly, when vision becomes severely impaired, the visual system begins firing off visual images.

• #19 When Blindness Induces Hallucinations

  https://www.retina-specialist.com/article/when-blindness-induces-hallucinations-1

  Charles Bonnet syndrome is a common although rather obscure and underresearched condition that is becoming ever more prevalent as the population ages and people live longer. It causes intricate, lifelike and recurring hallucinations in patients who have significant vision loss, especially in those diagnosed with macular degeneration, diabetic retinopathy or glaucoma. […] Medical experts have speculated about the causes of Charles Bonnet syndrome hallucinations, but the consensus is that the brain is reacting to a lack of visual input. As one experiences vision loss, the brain will continue to interpret visual data, even without corresponding visual input. Lacking that input, the brain will invent images, and visual brain cells will begin to fire spontaneously in order to compensate for lack of visual data. […] The same mechanism causes all of these conditions: the brain’s reaction to a lack of information from a sense or limb.

• #20 Charles Bonnet Syndrome: Evidence for a Generative Model in the Cortex? | PLOS Computational Biology

  https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1003134

  Several theories propose that the cortex implements an internal model to explain, predict, and learn about sensory data, but the nature of this model is unclear. […] CBS could be taken as indication that there is a generative model in the brain, specifically one that can synthesise rich, consistent visual representations even in the absence of actual visual input. The processes that lead to CBS are poorly understood. Here, we argue that a model recently introduced in machine learning, the deep Boltzmann machine (DBM), could capture the relevant aspects of (hypothetical) generative processing in the cortex. […] We show that homeostatic plasticity could serve to make the learnt internal model robust against e.g. degradation of sensory input, but overcompensate in the case of CBS, leading to hallucinations.

• #21 Charles Bonnet Syndrome: Evidence for a Generative Model in the Cortex? | PLOS Computational Biology

  https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1003134

  A neuron might track its current activity level by measuring its internal calcium levels, and several cellular mechanisms have been identified that could then implement its homeostatic adaptation. […] Hence, with visual input degraded due to eye disease or other defects in the visual pathways, homeostatic over compensation is a strong contender to be the neuronal cause underlying the emergence of hallucinations in CBS. […] The hypothesis we explored is that homeostatic regulation of neuronal firing rate in response to sensory deprivation underlies the emergence of hallucinations in CBS. […] The homeostatic mechanism as defined by Eq. 5 can be sufficient to restore the representations inferred over sensory input as to be suitable for classification. […] The emergence of hallucinatory representations coincided with a more rapid recovery of activity levels.

• #22 Charles Bonnet Syndrome: Evidence for a Generative Model in the Cortex? | PLOS Computational Biology

  https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1003134

  A neuron might track its current activity level by measuring its internal calcium levels, and several cellular mechanisms have been identified that could then implement its homeostatic adaptation. […] Hence, with visual input degraded due to eye disease or other defects in the visual pathways, homeostatic over compensation is a strong contender to be the neuronal cause underlying the emergence of hallucinations in CBS. […] The hypothesis we explored is that homeostatic regulation of neuronal firing rate in response to sensory deprivation underlies the emergence of hallucinations in CBS. […] The homeostatic mechanism as defined by Eq. 5 can be sufficient to restore the representations inferred over sensory input as to be suitable for classification. […] The emergence of hallucinatory representations coincided with a more rapid recovery of activity levels.

• #23 Azthena logo with the word Azthena

  https://www.news-medical.net/news/20151102/Charles-Bonnet-syndrome-an-interview-with-Dr-Dominic-ffytche.aspx

  Charles Bonnet syndrome is the name we give to the visual hallucinations associated with eye disease. The condition can occur as a result of any eye problem, including cataracts, diabetic retinal problems and glaucoma. There needs to be a moderate loss of vision for Charles Bonnet Syndrome to occur, which would be about half way down the chart at the opticians. […] Our brain scanning experiments, which we performed more than fifteen years ago now, have shown what happens in the brain when a person has a Charles Bonnet Syndrome hallucination. We found that there is a spontaneous increase in brain activity in particular regions of the visual cortex, the part of the brain that deals with vision, at the time of a hallucination and what a person sees in their hallucination depends on where the spontaneous increase occurs.

• #24 Charles Bonnet syndrome (CBS) – Macular Society

  https://www.macularsociety.org/macular-disease/macular-conditions/charles-bonnet-syndrome/

  Visual hallucinations can occur as a result of sight loss. […] When visual signals leave the eye they go to the back of the brain (the occipital lobe) to the primary visual receiving area. […] Scanning studies have revealed what happens in the brains of people while they hallucinate. […] With our eyes open, the visual brain expects to receive and process a flood of complex electrical signals. In people with eye disease or a break in the visual pathways, what was once a flood becomes a trickle. This leaves the visual areas of the brain with little to do. […] The idle visual brain cells, waiting for an appropriate trigger, begin to fire spontaneously. […] If this happens in the colour area, people experience hallucinations of colour; if in the object area, they see objects and so on.

• #25 Hallucinations & Macular Degeneration: What is Charles Bonnet Syndrome?

  https://www.brightfocus.org/resource/hallucinations-macular-degeneration-what-is-charles-bonnet-syndrome/

  The brain essentially creates these hallucinations because the normal amount of visual information coming from the eyes is reduced. […] In Charles Bonnet syndrome, the part of the brain responsible for vision substitutes illusions when it lacks input from the macula. […] As you lose vision, as the visual parts of the brain are no longer getting any input, they become hyperactive and excitable, and they start to fire spontaneously. […] When people have these simple geometrical hallucinations, the primary visual cortex is activated. […] When images are formed, a higher part of the visual cortex is involved in the temporal lobe. […] If there is an abnormal activity in the fusiform gyrus, they may hallucinate faces, and this is exactly what you find in some of these people. […] In the Charles Bonnet syndrome, you don’t go to those higher levels. You’re in these levels of inferior visual cortex where you have thousands and tens of thousands and millions of images, or figments, or fragmentary figments, all neurally encoded in particular cells or small clusters of cells. […] Instead of getting normal perception, you’re getting an anarchic, convulsive stimulation, or release, of all of these visual cells in the Infratemporal cortex.

• #26 Charles Bonnet Syndrome (CBS) – Gene Vision

  https://gene.vision/charles-bonnet-syndrome-cbs/

  Charles Bonnet Syndrome (CBS) is characterised by visual hallucinations in people affected by sight loss from any cause, including inherited eye disorders. […] CBS is estimated to affect 0.4-30% of people with sight loss, though it is considered to be underreported due to patients’ fears of being categorised as mentally ill, and a relative lack of awareness amongst the medical profession. […] If the retina or any part of this pathway is damaged, the stream of electrical impulses to the visual cortex is reduced. It is believed that in CBS, the brain cells in the visual cortex responds paradoxically by firing more signals, causing visual hallucinations. […] The image of the hallucination depends on which area of visual cortex is stimulated. For example, a stimulation in an area specialised for faces will cause the hallucination to have faces.

• #27 Visual release hallucinations – Wikipedia

  https://en.wikipedia.org/wiki/Visual_release_hallucinations

  Due to cone photoreceptor damage located in the macula, there is a significant reduction of visual input to the visual association cortex, stirring endogenous activation in the color areas and thus leading to colored hallucinations. […] The Deep Boltzmann Machine (DBM) is a way of utilizing an undirected probabilistic process in a neural framework. […] By using the DBM, researchers show that when sensory input is absent, neuron excitability is influenced, thus potentially triggering complex hallucinations. […] In periods of drowsiness, CBS related hallucinations are more prone to arise. […] Particularly in CBS, a shortage of acetylcholine at cortical locations should correspond to the onset of hallucinations.

• #28 What are the Challenges to Developing Treatments for Charles Bonnet Syndrome? – NHSJS

  https://nhsjs.com/2025/what-are-the-challenges-to-developing-treatments-for-charles-bonnet-syndrome/

  First, Carpenter et al believe that cortical hyperexcitability, extensive activity in the cerebral cortex, may be a factor for some CBS patients. When the cerebral cortex, which is responsible for cognitive function, sensory perception and various other functions, is excited, it leads to an imbalance in the inhibitory signals of the brain which can lead to the visual stimuli being interpreted as hallucinations. Conversely, they also have found information regarding the responsibilities of visual sensory inputs, which are vision stimulus, and contain inhibitory pathways that ensure proper visual perception and preventative measures of overload and distortion of visual information that is to be processed. CBS can cause these sensory inputs to suppress, which impact the feedforward and feedback connections in the brain which are dependent on the sensory inputs. These connections are incredibly complex and interconnected which also have fine-tuned functions that each influence each other to modify signal processing. Therefore, with the reduction of sensory input in the feedback input in the feedforward connections, it leads to receival of feedback signals from other areas of the brain that can possibly lead to CBS hallucinations in patients leading to a lack of acetylcholine, a neurotransmitter responsible for muscle contraction, memory, learning and attention. This finding is plausible because a lack of acetylcholine neurotransmitter leads to Alzheimer’s disease. This shows how CBS hallucinations experienced by patients from this cause can be induced by similar neurotransmitters regardless of the type of hallucination condition.

• #29 Charles Bonnet Syndrome: Complete Remission of Visual Hallucinations with Trazodone

  https://www.jneuropsychiatry.org/peer-review/charles-bonnet-syndrome-complete-remission-of-visual-hallucinations-with-trazodone-12999.html

  Charles Bonnet syndrome (CBS) is a neuro-ophthalmic condition that affects elderly people with visual impairment related to ophthalmological pathologies. […] Its mechanism involves spontaneous neuronal discharges of the visual cortex secondary to deafferentation of visual input. […] The etiology of CBS involves deafferentation of the visual system that leads to spontaneous neuronal discharges and consequently abnormal sensory perceptions. […] In CBS, spontaneous and/or stimulus-driven hyperexcitability of unimodal associative visual cortex underlies hallucinatory phenomena. […] The reason why only some individuals develop such hallucinations might be related to specific wiring conformation and/or presynaptic neurotransmitters concentrations and/or pre/post synaptic receptor avidities and densities. […] Trazodone is reported to block neuroplasticity through its 5-HT2C receptor antagonism, and perhaps the same “monoaminergic” effect could explain its efficacy in treating visual hallucinations.

• #30 What are the Challenges to Developing Treatments for Charles Bonnet Syndrome? – NHSJS

  https://nhsjs.com/2025/what-are-the-challenges-to-developing-treatments-for-charles-bonnet-syndrome/

  Findings also mention patients that experience CBS hallucinations had abnormalities, which were basilar and posterior cerebral arteries of the brain. The basilar artery is divided into branches of posterior cerebral arteries that then direct blood supply to the thalamus and occipital lobes of the brain. These abnormalities have a significant effect on hallucinations due to the processes of blood flow and responsibilities of these different areas of the brain corresponding to vision. As we process visual stimuli in our retina, they are sent to the thalamus responsible for directing various sensory stimuli to the different parts of the brain associated with each type of stimuli which are then sent to the occipital lobe which processes these visual stimuli into interpreting the images that our eyes see. An abnormality in the arteries that provide function to these parts of the brain can hinder accurate interpretation of visual stimuli which is what leads to these hallucinations to occur in patients. These compiled studies emphasize the neurological etiology of what causes CBS to be supported by how the occipital lobe and its counterparts play a crucial role in the onset of the condition for many patients. However, these theories don’t consider the overlooked brain activity occurring in other patients, ophthalmological factors or also the external factors that can also induce this condition.

• #31 What are the Challenges to Developing Treatments for Charles Bonnet Syndrome? – NHSJS

  https://nhsjs.com/2025/what-are-the-challenges-to-developing-treatments-for-charles-bonnet-syndrome/

  Findings also mention patients that experience CBS hallucinations had abnormalities, which were basilar and posterior cerebral arteries of the brain. The basilar artery is divided into branches of posterior cerebral arteries that then direct blood supply to the thalamus and occipital lobes of the brain. These abnormalities have a significant effect on hallucinations due to the processes of blood flow and responsibilities of these different areas of the brain corresponding to vision. As we process visual stimuli in our retina, they are sent to the thalamus responsible for directing various sensory stimuli to the different parts of the brain associated with each type of stimuli which are then sent to the occipital lobe which processes these visual stimuli into interpreting the images that our eyes see. An abnormality in the arteries that provide function to these parts of the brain can hinder accurate interpretation of visual stimuli which is what leads to these hallucinations to occur in patients. These compiled studies emphasize the neurological etiology of what causes CBS to be supported by how the occipital lobe and its counterparts play a crucial role in the onset of the condition for many patients. However, these theories don’t consider the overlooked brain activity occurring in other patients, ophthalmological factors or also the external factors that can also induce this condition.

• #32 Charles Bonnet syndrome: a condition of the visually impaired – Dhooge – Annals of Eye Science

  https://aes.amegroups.org/article/view/6863/html

  The risk of CBS seems to correlate with the extent of vision loss, rather than the underlying ophthalmic diagnosis. […] In addition, recent loss of visual acuity also seems to be a risk factor for the development of CBS. […] Subhi et al. report various diseases along the visual pathway that result in CBS including cataract, age related macular degeneration (AMD), and glaucoma. […] In addition, neurological diseases that cause a visual field defect may also result in CBS. […] A major difficulty in studying the collective data on CBS lies within the variable definition, or lack thereof, of this syndrome. […] Indeed, in the meta-analysis of Subhi et al., a clear definition of CBS was absent in six out of the 11 studies. […] The criteria as proposed by Teunisse et al. also do not include visual impairment as a vital component of the syndrome, when in fact they found a clear association between visual impairment and CBS.

• #33 Charles Bonnet syndrome: a condition of the visually impaired – Dhooge – Annals of Eye Science

  https://aes.amegroups.org/article/view/6863/html

  The risk of CBS seems to correlate with the extent of vision loss, rather than the underlying ophthalmic diagnosis. […] In addition, recent loss of visual acuity also seems to be a risk factor for the development of CBS. […] Subhi et al. report various diseases along the visual pathway that result in CBS including cataract, age related macular degeneration (AMD), and glaucoma. […] In addition, neurological diseases that cause a visual field defect may also result in CBS. […] A major difficulty in studying the collective data on CBS lies within the variable definition, or lack thereof, of this syndrome. […] Indeed, in the meta-analysis of Subhi et al., a clear definition of CBS was absent in six out of the 11 studies. […] The criteria as proposed by Teunisse et al. also do not include visual impairment as a vital component of the syndrome, when in fact they found a clear association between visual impairment and CBS.

• #34 Charles Bonnet syndrome: a condition of the visually impaired – Dhooge – Annals of Eye Science

  https://aes.amegroups.org/article/view/6863/html

  The risk of CBS seems to correlate with the extent of vision loss, rather than the underlying ophthalmic diagnosis. […] In addition, recent loss of visual acuity also seems to be a risk factor for the development of CBS. […] Subhi et al. report various diseases along the visual pathway that result in CBS including cataract, age related macular degeneration (AMD), and glaucoma. […] In addition, neurological diseases that cause a visual field defect may also result in CBS. […] A major difficulty in studying the collective data on CBS lies within the variable definition, or lack thereof, of this syndrome. […] Indeed, in the meta-analysis of Subhi et al., a clear definition of CBS was absent in six out of the 11 studies. […] The criteria as proposed by Teunisse et al. also do not include visual impairment as a vital component of the syndrome, when in fact they found a clear association between visual impairment and CBS.

• #35 What is Charles Bonnet syndrome, the eye condition that causes hallucinations?

  https://theconversation.com/what-is-charles-bonnet-syndrome-the-eye-condition-that-causes-hallucinations-122322

  The causes of blindness that lead to Charles Bonnet syndrome are usually macular degeneration, glaucoma, diabetes, stroke and injury – but any disease that leads to blindness may cause Charles Bonnet syndrome. […] Hallucinations may disappear if the cause of vision loss can be corrected (for example, if severe cataracts were causing blindness and the patient has a cataracts operation). […] Unfortunately though, generally the causes of vision loss that lead to Charles Bonnet syndrome can’t be treated.

• #36 Charles Bonnet Syndrome – StatPearls – NCBI BookshelfTwitterFacebookLinkedInGitHubNCBI Insights BlogTwitterFacebookYoutube

  https://www.ncbi.nlm.nih.gov/books/NBK585133/

  Charles Bonnet syndrome (CBS) is a phenomenon characterized by complex visual hallucinations in visually challenged patients but otherwise psychologically normal. […] CBS can manifest when there is a lesion at any level of the visual system, and typically patients manifest with a loss of central visual acuity. CBS is also associated with ARMD with a secondary decline in visual acuity. […] The current and most commonly accepted theory for the visual hallucinations seen in CBS is that visual sensory deafferentation results in disinhibitions of cortical regions affecting vision. […] Ultimately, this disinhibition leads to spontaneous firing of these vision-associated regions, resulting in hallucinations. […] The proposed theory for CBS is the phantom limb pain theory. Phantom limb pain theory explains a feeling of pain even when the limb has been removed. The patient feels pain even though the limb has been removed. Similarly, patients with CBS may have visual sensations despite being unable to see them. […] The pathophysiology of CBS first starts with any factor that leads to loss of vision. These factors which can affect any part of the visual pathway commonly include cataracts, glaucoma, diabetic retinopathy, age-related macular degeneration, and cerebral infarction affecting the visual cortex.

• #37 Charles Bonnet syndrome: a condition of the visually impaired – Dhooge – Annals of Eye Science

  https://aes.amegroups.org/article/view/6863/html

  The risk of CBS seems to correlate with the extent of vision loss, rather than the underlying ophthalmic diagnosis. […] In addition, recent loss of visual acuity also seems to be a risk factor for the development of CBS. […] Subhi et al. report various diseases along the visual pathway that result in CBS including cataract, age related macular degeneration (AMD), and glaucoma. […] In addition, neurological diseases that cause a visual field defect may also result in CBS. […] A major difficulty in studying the collective data on CBS lies within the variable definition, or lack thereof, of this syndrome. […] Indeed, in the meta-analysis of Subhi et al., a clear definition of CBS was absent in six out of the 11 studies. […] The criteria as proposed by Teunisse et al. also do not include visual impairment as a vital component of the syndrome, when in fact they found a clear association between visual impairment and CBS.

• #38 Charles Bonnet Syndrome – Rare Awareness Rare Education

  https://rareportal.org.au/rare-disease/charles-bonnet-syndrome/

  Charles Bonnet syndrome (CBS) is a vision-related condition, in which individuals see images that are not actually present (phantom images) due to decreasing or loss of vision. CBS is a distinct clinical condition, as recognised by the World Health Organization (WHO), and is not due to psychosis, dementia, or other neurodegenerative issues. […] The cause of the phantom visions is not well understood, but it is thought to be due to the brain reacting to the decrease in or loss of vision. […] CBS is often described in individuals with conditions that affect their vision, such as age-related macular degeneration (ARMD), glaucoma, cataracts, and retinal abnormalities. The syndrome though is not restricted to eye disease but can be elicited when there is any form of damage along the visual pathways from the optic nerve to the visual cortex, such as due to brain injuries, brain tumour, and stroke.

• #39 Visual hallucinations in blindness | MedLink Neurology

  https://www.medlink.com/articles/visual-hallucinations-in-blindness

  High-frequency bursts of synchronized though nonepileptic neural activity in areas of deafferentated cortex may be necessary for these hallucinations. […] Presumably, a generative model exists in the brain that can synthesize consistent visual representations even without actual visual input. […] The development of visual hallucinations in patients with hemianopia after stroke is inversely correlated with lesion size and specifically requires a relatively small lesion that includes loss of the striate cortex but that spares Brodmann areas 19, 20, and 37.

• #40 Visual hallucinations in blindness | MedLink Neurology

  https://www.medlink.com/articles/visual-hallucinations-in-blindness

  High-frequency bursts of synchronized though nonepileptic neural activity in areas of deafferentated cortex may be necessary for these hallucinations. […] Presumably, a generative model exists in the brain that can synthesize consistent visual representations even without actual visual input. […] The development of visual hallucinations in patients with hemianopia after stroke is inversely correlated with lesion size and specifically requires a relatively small lesion that includes loss of the striate cortex but that spares Brodmann areas 19, 20, and 37.

• #41 EyeRounds.org: Charles Bonnet Syndrome

  http://eyerounds.org/cases/302-Charles_Bonnet.htm

  Charles Bonnet Syndrome is relatively common, with an estimated prevalence of 10-40% in visually impaired patients. The visual hallucinations in CBS have been described with conditions of visual loss affecting any part of the visual system, including the eye, optic nerve, and brain, and may occur in almost any acquired disorder of the visual system. […] Visual hallucinations in the setting of CBS have a variety of manifestations. Some patients report simple images, such as lines, flashes of light, or patterns. Other patients may experience more complex visual hallucinations such as those of animals or people. […] One of the most important distinguishing features of visual hallucinations secondary to CBS is that the patient generally has insight into their condition and knows that the images are not real. Another characteristic of hallucinations unique to CBS includes that they predominately occur when the eyes are open, and tend to resolve when a patient closes their eyes or looks away. […] One study found that the hallucinations tend to be more prevalent in the setting of sensory deprivation, such as in low light situations, in social isolation, and general inactivity.

• #42 Visual release hallucinations – Wikipedia

  https://en.wikipedia.org/wiki/Visual_release_hallucinations

  Due to cone photoreceptor damage located in the macula, there is a significant reduction of visual input to the visual association cortex, stirring endogenous activation in the color areas and thus leading to colored hallucinations. […] The Deep Boltzmann Machine (DBM) is a way of utilizing an undirected probabilistic process in a neural framework. […] By using the DBM, researchers show that when sensory input is absent, neuron excitability is influenced, thus potentially triggering complex hallucinations. […] In periods of drowsiness, CBS related hallucinations are more prone to arise. […] Particularly in CBS, a shortage of acetylcholine at cortical locations should correspond to the onset of hallucinations.

• #43 UT Health Austin | Visual Release Hallucinations (Charles Bonnet…

  https://uthealthaustin.org/conditions/charles-bonnet-syndrome

  Visual release hallucinations occur most often among the elderly population as they are the most likely age group to have optical conditions such as macular degeneration that affect eyesight. […] Charles Bonnet syndrome is most common in individuals 70-85 years or older. […] Visual impairment or vision loss, involving either one or both eyes, can cause condition onset.

• #44 Visual release hallucinations – Wikipedia

  https://en.wikipedia.org/wiki/Visual_release_hallucinations

  Due to cone photoreceptor damage located in the macula, there is a significant reduction of visual input to the visual association cortex, stirring endogenous activation in the color areas and thus leading to colored hallucinations. […] The Deep Boltzmann Machine (DBM) is a way of utilizing an undirected probabilistic process in a neural framework. […] By using the DBM, researchers show that when sensory input is absent, neuron excitability is influenced, thus potentially triggering complex hallucinations. […] In periods of drowsiness, CBS related hallucinations are more prone to arise. […] Particularly in CBS, a shortage of acetylcholine at cortical locations should correspond to the onset of hallucinations.

• #45 Charles Bonnet Syndrome: Symptoms and Treatment | Doctor

  https://patient.info/doctor/charles-bonnet-syndrome-pro

  The phenomenon is seen in patients with moderate or severe visual impairment. It can occur spontaneously as the vision declines or it may be precipitated, in predisposed individuals, by concurrent illness such as infections elsewhere in the body. […] It is not clear why CBS develops or why some individuals appear to be predisposed to it. It is particularly noted in patients with advanced macular degeneration. It has been suggested that reduced or absent stimulation of the visual system leads to increased excitability of the visual cortex (deafferentation hypothesis). This release phenomenon is compared to phantom limb symptoms after amputation. […] Some researchers have questioned whether CBS may, in some patients, be an early stage of dementia with Lewy bodies. This condition is certainly in the list of differential diagnoses.

• #46 Azthena logo with the word Azthena

  https://www.news-medical.net/news/20151102/Charles-Bonnet-syndrome-an-interview-with-Dr-Dominic-ffytche.aspx

  The answer to that is that it’s the brains normal response to vision being lost through eye problems. When you have eye disease, much less information carried by neural signals is travelling from the eye to the brain. The brain responds by becoming more excitable and it’s this excitability that causes the spontaneous increases of activity and hence, the hallucinations.

• #47 Visual hallucinations in blindness | MedLink Neurology

  https://www.medlink.com/articles/visual-hallucinations-in-blindness

  Bonnet hallucinations are thought to result from a „release” mechanism associated with modality-specific sensory deprivation, ie, „phantom vision” akin to phantom limbs in patients with loss of somatosensory input after an amputation. […] The complex nature of Bonnet hallucinations indicates that they are generated in the visual association cortex. […] In support of a release mechanism for Bonnet hallucinations, sensory deprivation and a low level of arousal favor development of the hallucinations but are not required for their development. […] The specific pathophysiological mechanisms involved in Bonnet syndrome are still being investigated, but many authors have suggested a „release” mechanism associated with modality-specific sensory deprivation or deafferentation. […] Deafferentation produces an increase in excitability of the deafferentated neurons and an increase in spontaneous activity.

• #48 Visual hallucinations in blindness | MedLink Neurology

  https://www.medlink.com/articles/visual-hallucinations-in-blindness

  High-frequency bursts of synchronized though nonepileptic neural activity in areas of deafferentated cortex may be necessary for these hallucinations. […] Presumably, a generative model exists in the brain that can synthesize consistent visual representations even without actual visual input. […] The development of visual hallucinations in patients with hemianopia after stroke is inversely correlated with lesion size and specifically requires a relatively small lesion that includes loss of the striate cortex but that spares Brodmann areas 19, 20, and 37.

• #49 Charles Bonnet Syndrome – Neuropedia

  https://neuropedia.net/articles/neurology/neuro-ophthalmology/charles-bonnet-syndrome/

  Charles Bonnet syndrome is a visual hallucination caused by the brain adapting to significant vision loss. […] Charles Bonnet Syndrome (CBS), also called phantom vision, is an illness where cognitively normal people experience simple or complex and consistent visual hallucinations, due to damage along the visual pathway. […] CBS can be caused by any factor affecting the visual pathway, extending from the visual cortex down to the eyes. […] The precise pathogenesis of CBS is still unknown. However, 2 main theories are suggested to explain the visual hallucinations experienced during CBS: The deprivation theory suggests that diminution in sensory input leads to the production of spontaneous images from the visual association cortex, resulting in visual hallucinations. […] The release theory suggests that a lesion of the visual pathway causes abnormal signals to be sent to the visual cortex. The hallucinations result from a combination of normal and abnormal signals at the level of the visual association cortex.

• #50 What are the Challenges to Developing Treatments for Charles Bonnet Syndrome? – NHSJS

  https://nhsjs.com/2025/what-are-the-challenges-to-developing-treatments-for-charles-bonnet-syndrome/

  The visual ventral stream process that enables object recognition through linking visual input to memories primarily made of the occipital and the temporal lobe is also a prevalent factor in patients experiencing hallucinations. Carpenter and Vale et al, both mention that groups of CBS patients exhibited increased blood flow and overactivity in the striatum, lateral temporal cortex, and thalamus. This increased blood flow is because all 3 of these brain regions work together to execute the function of the visual ventral stream. Specifically in this stream, the striatum controls reactions to what we interpret from visual stimuli in our occipital lobe, and the lateral temporal cortex is responsible for object and facial recognition and other types of complex processing. This helps explain how regions of the brain that aren’t associated with vision are connected to regions of the brain that executive visual functions.

• #51 What are the Challenges to Developing Treatments for Charles Bonnet Syndrome? – NHSJS

  https://nhsjs.com/2025/what-are-the-challenges-to-developing-treatments-for-charles-bonnet-syndrome/

  The visual ventral stream process that enables object recognition through linking visual input to memories primarily made of the occipital and the temporal lobe is also a prevalent factor in patients experiencing hallucinations. Carpenter and Vale et al, both mention that groups of CBS patients exhibited increased blood flow and overactivity in the striatum, lateral temporal cortex, and thalamus. This increased blood flow is because all 3 of these brain regions work together to execute the function of the visual ventral stream. Specifically in this stream, the striatum controls reactions to what we interpret from visual stimuli in our occipital lobe, and the lateral temporal cortex is responsible for object and facial recognition and other types of complex processing. This helps explain how regions of the brain that aren’t associated with vision are connected to regions of the brain that executive visual functions.

• #52 Charles Bonnet Syndrome | Macular Disease Foundation Australia

  https://www.mdfoundation.com.au/about-macular-disease/other-conditions/charles-bonnet-syndrome/

  When mentally healthy people with significant vision loss experience vivid, recurrent visions, it is called Charles Bonnet syndrome. […] The simplest explanation for CBS is that when vision is lost, your brain isnt receiving as many pictures. So your brain releases new fantasy pictures, or old pictures that it has stored, and you experience them as though they were real. […] Charles Bonnet syndrome is caused by failing eyesight. It is not a mental health problem. […] For most people, the best way to manage the condition is just knowing CBS is a result of their vision loss and not other health problems.

• #53 Charles Bonnet Syndrome – IALVS

  https://ialvs.com/ways-we-can-help/what-is-a-low-vision-exam/low-vision-eye-diseases/charles-bonnet-syndrome/

  Charles Bonnet syndrome (CBS) is a condition that can develop after a person experiences vision loss. It leads to visual hallucinations of all types– such as seeing a vase of flowers on a table that’s really empty or seeing a distorted face peering in the window. […] Charles Bonnet syndrome is not widely recognized, and many people fear that they may have dementia or a serious mental health problem. Really, visual hallucinations are a normal response of the brain when faced with vision loss. […] With healthy eyesight, the retina receives light that enters your eye and converts it into visual messages for the brain. The brain interprets the visual messages so you can see them. When a person suffers vision loss from a disease such as glaucoma, age-related macular degeneration, or diabetic retinopathy, the visual system can’t process new images. To compensate for the lack of visual data that’s being transmitted through your eyes, the brain creates images or recalls stored images and displays them for you to see. These “made-up images” are the visual hallucinations of Charles Bonnet syndrome.

• #54 Charles Bonnet Syndrome – Fighting Blindness incorporating The National League of the Blind

  https://www.fightingblindness.ie/living-with-sight-loss/eye-conditions/charles-bonnet-syndrome/

  First noted in 1760, Charles Bonnet Syndrome (CBS, also known as phantom vision syndrome) describes the condition in which visual hallucinations are experienced by people of any age living with significant sight loss. […] The underlying mechanism by which this condition presents is unknown, although a number of theories exist. Research has suggested that a more significant loss of vision may correspond to an increased susceptibility to developing this condition. […] At present, many research groups are trying to confirm the underlying cause of this condition. In finding out more about the cause, it may reveal ways in which these hallucinations can be cured or treated.

• #55 Charles Bonnet syndrome – Retina UK

  https://retinauk.org.uk/information-and-support/about-inherited-sight-loss/types-of-inherited-sight-loss/charles-bonnet-syndrome/

  These hallucinations are caused by failing eyesight and are a normal response the brain has to the loss of vision. They’re not caused by a mental health problem or dementia. […] Researchers who are investigating CBS have discovered it is not a mental health condition, but is in fact caused entirely by loss of sight. CBS is caused by your brain reacting to your loss of vision. It can sometimes try to fill the ‘gaps’. […] It is important you tell your doctor if you are experiencing hallucinations so that they can rule out any other conditions. It can also occur when another medical condition such as Parkinson’s disease, a stroke, or an accident affects parts of the brain that deal with sight. […] UK researchers have discovered that passing a weak electrical current between electrodes on a person’s scalp may lead to a reduction in frequency of the visual hallucinations experienced by some people living with sight loss. […] Prof Dominic Ffytche will provide an explanation of what Charles Bonnet Syndrome is, the science behind it, and share some potential coping strategies for people who experience visual hallucinations.

• #56 Charles Bonnet Syndrome (CBS) – Gene Vision

  https://gene.vision/charles-bonnet-syndrome-cbs/

  It is important to remember that CBS hallucinations only involve sight. If other senses (hearing, smelling, tasting or touching) are involved as well then it is not considered to be CBS. […] As it is widely believed that visual hallucinations in CBS stem from the hyperactivity of brain cells in the visual cortex, TDCS aims to minimise or eliminate these hallucinations by modulating this area of the brain. […] Further research into CBS is required in order to gain a deeper understanding of the cause and how best to manage symptoms.

• #57 Charles Bonnet Syndrome: Evidence for a Generative Model in the Cortex? | PLOS Computational Biology

  https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1003134

  A neuron might track its current activity level by measuring its internal calcium levels, and several cellular mechanisms have been identified that could then implement its homeostatic adaptation. […] Hence, with visual input degraded due to eye disease or other defects in the visual pathways, homeostatic over compensation is a strong contender to be the neuronal cause underlying the emergence of hallucinations in CBS. […] The hypothesis we explored is that homeostatic regulation of neuronal firing rate in response to sensory deprivation underlies the emergence of hallucinations in CBS. […] The homeostatic mechanism as defined by Eq. 5 can be sufficient to restore the representations inferred over sensory input as to be suitable for classification. […] The emergence of hallucinatory representations coincided with a more rapid recovery of activity levels.

• #58 Charles Bonnet Syndrome | Discover Causes, Symptoms & Treatments | Fight For Sight

  https://www.fightforsight.org.uk/a-z-eye-conditions/charles-bonnet-syndrome/

  One study will investigate the possibility that peripheral (‘side’) vision is more ‘suggestible’ than central vision. The second study will use a special type of MRI scan to measure the levels of chemicals in the visual areas of the brain to see whether they are abnormal in people with Charles Bonnet Syndrome.

• #59 Final Piece of the Puzzle: Charles Bonnet Syndrome | Conexiant

  https://vision-umbraco.euwest01.umbraco.io/issues-folder/2023/3/final-piece-of-the-puzzle-charles-bonnet-syndrome/

  We are now probing these mechanisms at both the University of Oxford and Anglia Ruskin University in Cambridge. […] When we put the results from both studies together alongside previous research from other teams we hope to build a more comprehensive picture of whats actually happening in the brains of people with CBS.

• #60 Final Piece of the Puzzle: Charles Bonnet Syndrome | Conexiant

  https://vision-umbraco.euwest01.umbraco.io/issues-folder/2023/3/final-piece-of-the-puzzle-charles-bonnet-syndrome/

  Jasleen Jolly discusses her ongoing research studies investigating the underlying mechanisms causing the hallucinations experienced in Charles Bonnet Syndrome. […] Additionally, our understanding of CBS and the underlying mechanisms are not that much further along from when I was first taught about it at university or even from the first descriptions of the syndrome by Charles Bonnet himself in 1760! […] As it occurs across all eye diseases and manifests in the same way (regardless of what is happening at the level of the eye), it is clearly happening further along in the visual pathway in the brain. […] One theory of particular interest to us is that CBS is a result of the imbalance between whats coming in from the visual system and whats coming from upstream. […] Given the low vision of patients with CBS, there isnt much feed-forward but the feedback is still occurring, which is being seen in the form of hallucinations.

• #61 Final Piece of the Puzzle: Charles Bonnet Syndrome | Conexiant

  https://vision-umbraco.euwest01.umbraco.io/issues-folder/2023/3/final-piece-of-the-puzzle-charles-bonnet-syndrome/

  Jasleen Jolly discusses her ongoing research studies investigating the underlying mechanisms causing the hallucinations experienced in Charles Bonnet Syndrome. […] Additionally, our understanding of CBS and the underlying mechanisms are not that much further along from when I was first taught about it at university or even from the first descriptions of the syndrome by Charles Bonnet himself in 1760! […] As it occurs across all eye diseases and manifests in the same way (regardless of what is happening at the level of the eye), it is clearly happening further along in the visual pathway in the brain. […] One theory of particular interest to us is that CBS is a result of the imbalance between whats coming in from the visual system and whats coming from upstream. […] Given the low vision of patients with CBS, there isnt much feed-forward but the feedback is still occurring, which is being seen in the form of hallucinations.

• #62 Visual hallucinations and eye disease: Why Charles Bonnet syndrome is important to eye care pra… – College of Optometrists

  https://www.college-optometrists.org/professional-development/college-journals/optometry-in-practice/volume-13,-issue-3/2012-09-visualhallucinationsandeyedisease_whycharl

  This paper outlines the demographics, clinical features, current theories of pathogenesis and management of Charles Bonnet Syndrome. […] CBS is often undiagnosed due to lack of voluntary patient disclosure and limited clinician awareness. […] This paper outlines the demographics, clinical features, current theories of pathogenesis and management of this intriguing phenomenon.

• #63 Charles Bonnet Syndrome – IALVS

  https://ialvs.com/ways-we-can-help/what-is-a-low-vision-exam/low-vision-eye-diseases/charles-bonnet-syndrome/

  Studies have shown that low vision rehabilitation may reduce the frequency of Charles Bonnet hallucinations in patients with this condition. Effective rehabilitation strategies include using personalized low vision devices to enable improved visual function for the type of vision loss that each person has experienced.

• #64 When Blindness Induces Hallucinations

  https://www.retina-specialist.com/article/when-blindness-induces-hallucinations-1

  Charles Bonnet syndrome is a common although rather obscure and underresearched condition that is becoming ever more prevalent as the population ages and people live longer. It causes intricate, lifelike and recurring hallucinations in patients who have significant vision loss, especially in those diagnosed with macular degeneration, diabetic retinopathy or glaucoma. […] Medical experts have speculated about the causes of Charles Bonnet syndrome hallucinations, but the consensus is that the brain is reacting to a lack of visual input. As one experiences vision loss, the brain will continue to interpret visual data, even without corresponding visual input. Lacking that input, the brain will invent images, and visual brain cells will begin to fire spontaneously in order to compensate for lack of visual data. […] The same mechanism causes all of these conditions: the brain’s reaction to a lack of information from a sense or limb.

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