Charles Bonnet syndrome

What is Charles Bonnet syndrome

Charles Bonnet syndrome is a condition where visual hallucinations are experienced by people with vision loss who don’t have a mental health issue. These hallucinations are sometimes called ‘phantom images’ or ‘phantom vision’. These phantom images co-exist with one’s usual visual experience. The hallucinations people with Charles Bonnet syndrome experience can be described as simple or complex. Simple hallucinations include shapes and patterns, while complex include images of people, vehicles, animals, and plants. Hallucination episodes can range from a few seconds to hours and may recur over the course of several days to years 1).

Most people who have Charles Bonnet syndrome have very poor vision, but researchers say the Charles Bonnet syndrome can also affect people who have only a slight loss of vision or even normal vision.

Charles Bonnet syndrome can affect people of any age, but it’s more likely to occur if you have significant vision loss later in life. You can have Charles Bonnet syndrome if you have macular degeneration, diabetic retinopathy or glaucoma.

Experts do not know what causes these images, but some think the brain invents fantasy pictures or releases old pictures that are stored there to compensate for not receiving images through the eyes.

There are many underlying diseases of vision loss that are associated with Charles Bonnet syndrome, such as macular degeneration and stroke. Hallucinations may resolve in instances where the the underlying vision issue can be corrected (such as with cataracts).

There is no single treatment for Charles Bonnet syndrome, although in many cases some reassurance may be enough to help you. Realizing that Charles Bonnet syndrome is not a mental health issue may help you live with it.

Some people are taught to block their hallucinations, while others may benefit from antipsychotic medications 2).

It can also help to know that for most people, the hallucinations stop within 12-18 months.

If you experience more disturbing images, to help manage the symptoms you could consider the following:

  • Visit your eye specialist so they can monitor your vision, prescribe the right spectacles and remove any cataracts.
  • Improve your lighting at home, reduce any glare and use a magnifier for close work. These simple changes have helped some people. Contact your local low-vision rehabilitation service provider for assistance.
  • Stimulate the brain and senses since this may reduce the likelihood of symptoms. Activities such as listening to a talking book, exercising — even doing some gardening — may help.
  • Socialize more or join a support group. Social isolation has been shown to increase the likelihood of experiencing phantom images.
  • Where possible, reduce stress and anxiety — for example through a hobby or creative activity — since stress tends to make the condition worse. Phantom images can become more intense and occur more often when you are stressed.
  • Talk to your doctor about medicines or electromagnetic stimulation. (This relatively new treatment increases or decreases brain cell activity depending on the symptoms being experienced).

Charles Bonnet syndrome causes

Experts do not know what causes Charles Bonnet syndrome, but some think the brain invents fantasy pictures or releases old pictures that are stored there to compensate for not receiving images through the eyes.

There are two principal ways of contracting Charles Bonnet syndrome:

  • The most common is as a result of a wide range of eye diseases.
  • Less common is a consequence of other clinical conditions (e.g., stroke) or various eye procedures.

Medical conditions such as stroke, epilepsy and brain tumor can trigger Charles Bonnet syndrome when they affect the visual regions of the brain. A complication of Multiple Sclerosis (MS) and various eye procedures/treatments can also elicit Charles Bonnet syndrome when they disrupt a region of the visual pathway.

Charles Bonnet syndrome and macular degeneration

One of the most consistent findings of Charles Bonnet syndrome in relation to eye disease is that age-related macular degeneration (ARMD) poses a significant risk. This link is not unexpected given that macular degeneration is one of the leading causes of blindness in the Western world. Current estimates suggest somewhere between 20 – 40% of people living with macular degeneration will develop Charles Bonnet syndrome and the figure is believed to jump to 60% in advanced cases.

Despite this strong correlation, precious few macular degeneration books (for the public) provide any coverage of Charles Bonnet syndrome. Further, the syndrome is mentioned in only ~25% of contemporary ophthalmology text books. This suggests that crucial information is not reaching the general layperson but perhaps more concerningly, future health professionals. This unfortunate state of affairs serves only to reproduce the maxim ‘out of sight, out of mind.’

Dry and wet forms of macular degeneration

Charles Bonnet syndrome risk applies to both the ‘dry’ and ‘wet’ forms of age-related macular degeneration (ARMD) although as the wet form can affect vision far more dramatically, it represents a more acute risk.

The ‘dry’ form of macular degeneration is the most common type of age-related macular degeneration (ARMD). It is a more slow moving form such that deterioration of the macular tends to be gradual. Charles Bonnet syndrome symptoms can appear weeks, months and even years after the initial age-related macular degeneration diagnosis.

The ‘wet’ form refers to where the blood vessels feeding the retina (a) start to abnormally sprout and branch out and can intrude into retinal layers and/or (b) burst and bleed into the eye. The leakage of blood into the retina needs to receive urgent attention as vision loss in this situation tends to be rapid. In this wet form of age-related macular degeneration, Charles Bonnet syndrome symptoms tend to appear much sooner.

There are two major treatments for the wet form of age-related macular degeneration which aim to inhibit the growth of new blood vessels. One is called Avastin and the other Lucentis.

It needs to be noted that Avastin – also known as Bevacizumab – has been occasionally reported to trigger Charles Bonnet syndrome. There are several clinical papers that discuss this and can be supplied upon request.

Recently, two studies have suggested there may be an increased risk of Charles Bonnet syndrome if someone living with macular degeneration is also taking a certain form of heartburn medication.

Recommendations

  • Routine screening for, and forewarning of Charles Bonnet syndrome during the initial consultations with the eye specialist could prevent much needless suffering and anxiety.
  • For those who may be already experiencing Charles Bonnet syndrome symptoms, the valuable reassurance that can be provided by the eye specialist (i.e., that they’re not losing their mind) can put to rest genuine fears and doubts.
  • For those yet to experience any signs of Charles Bonnet syndrome, the doctor’s forewarning can be readily drawn upon if something visually unusual occurs down the track.
  • That eye specialists planning to treat the ‘wet’ form of age-related macular degeneration with Avastin notify patients of the possible risks associated with the use of this procedure in order that an informed decision can be made.
  • Family doctors and other health care professionals being alert to the above also. This can provide an additional layer of (clinical) support.
  • Stress and anxiety can emerge from living with age-related macular degeneration. Stress has also been found to be a risk factor for inducing or exacerbating Charles Bonnet syndrome symptoms. Therefore, attempts to keep stress levels to a minimum is advised.

Charles Bonnet syndrome and dementia

The relationship between these two conditions is blurry. Because Charles Bonnet syndrome is not readily known by medical practitioners, its symptoms can sometimes be misread for dementia. But over and above this, there are some who claim that Charles Bonnet syndrome is a stepping stone to dementia. This is a controversial idea that has its supporters and detractors.

On the topic of Charles Bonnet syndrome and dementia, there are three aspects to be considered:

(i) Charles Bonnet syndrome is often presumed to be, or misdiagnosed as, dementia.

Charles Bonnet syndrome can be misread as a hallmark sign of dementia (or other clinical conditions associated with visual hallucinations). This is however sometimes due to clinical neglect. Many clinicians are unaware of Charles Bonnet syndrome as a genuine clinical entity in its own right.

There are unfortunate instances of Charles Bonnet syndrome-affected individuals being misdiagnosed and inappropriately placed on powerful psychotropic medications that often are counter-productive. Some have even been referred to institutional care.

(ii) The claim has been made that Charles Bonnet syndrome may be an early indicator of dementia.

To this day, this notion remains a matter of conjecture. Whilst there are a handful of researchers who suggest that Charles Bonnet syndrome lies on a continuum with dementia, others remains suspect of any clear links between the two conditions.

The Charles Bonnet syndrome Foundation currently remains in the latter camp given that:

  • Cases of subsequent dementia (post-Charles Bonnet syndrome diagnosis) are not common.
  • In one of the leading journal articles supporting the idea of Charles Bonnet syndrome as a marker for dementia 3), more than half of the subjects did not have initial insight into the unreality of what they saw. This calls into question whether these subjects actually had Charles Bonnet syndrome to begin with.
  • There have been instances where subjects were deemed to have Charles Bonnet syndrome even though their Mini-Mental State Examination (ie. test for mental processing ability) was only 18/30. This is questionable given that intact cognition tends to be a hallmark of the Charles Bonnet syndrome diagnosis.
  • Initial screening of individuals may have failed to pick up mental impairment (subtle and not so subtle).

(iii) It is certainly possible that both Charles Bonnet syndrome and dementia can co-exist in an individual.

In advancing years, it is not unusual for people to be living with multiple ailments/diseases. Therefore, it is conceivable that an individual can live with both conditions.

Living with both Charles Bonnet syndrome and a form of dementia would be a very difficult burden on both personal and family fronts affecting mobility, relationships, self-esteem etc. Whilst information is freely available for either of these two conditions, there is a dearth of information for those living with both and how they may interact with one another. There is an urgent need for research in this area.

Charles Bonnet syndrome and Stroke

When a stroke occurs in the visual regions of the brain, there is an increased chance of visual disturbances including Charles Bonnet syndrome 4).

There are two forms of stroke, which are also known as ‘brain attacks’. The most common form is whereby there is an interruption to blood flow in a specific region of the brain (infarct). The less common form is where there is a rupturing of a brain blood vessel. Some effects of a stroke are widely known such as partial to total paralysis to one side of the body. Less well known is that in ~20% of cases of stroke it leads to various visual or perceptual disturbances.

This includes:

  • visual field defects
  • visual neglect (neglecting one side of space)
  • impaired reading ability (alexia)
  • impaired ability to recognise visual objects (visual agnosia)
  • impaired ability to recognise colours (achromatopsia) or faces (prosopagnosia)
  • visual hallucinations/phantom images/Charles Bonnet syndrome.

Unlike most cases of Charles Bonnet syndrome due to eye disease, in many instances of stroke-induced Charles Bonnet syndrome, the affected person retains central vision (visual acuity) even though they may well experience some form of visual field loss.

Note that:

  • the effects of a stroke can be incredibly wide ranging and the above is just a small selection.
  • Charles Bonnet syndrome is a diagnosis of exclusion. Therefore, one must first exclude other possibilities including: Parkinson’s disease, dementia, delirium, psychosis, drug and alcohol withdrawal, side effect of prescribed medication, epilepsy.

Charles Bonnet syndrome and Brain tumor or surgery

Charles Bonnet syndrome can occur from damage anywhere along the visual system. This begins from the eye ball, through the central visual pathway and to the visual regions of the brain. Brain tumors and aneurysms (ballooning of a brain blood vessel) have been known to result in vision loss and sometimes, Charles Bonnet syndrome.

Furthermore, neurosurgical procedures (i.e., brain surgery) to remove a tumor or aneurysm have also been known to trigger Charles Bonnet syndrome 5). Interestingly, the Charles Bonnet syndrome phantom images seem to typically occur in the regions where visual field loss has occurred.

Charles Bonnet syndrome and Multiple Sclerosis

It has been reported that over 50% of people living with multiple sclerosis (MS) will experience at least one visual disturbance 6). A major cause of visual disturbance in multiple sclerosis (MS) is optic neuritis (swelling of the optic nerve). The range of visual disturbances include blurred or decreased vision, dilution of perceived colour and visual field loss. What is less well known is that visual disturbances experienced by those living with MS can also extend to Charles Bonnet syndrome.

Optic neuritis is a common complication of multiple sclerosis and can lead to acute vision loss. It has often been suggested that Charles Bonnet syndrome is more likely to occur as a result of sudden vision loss (e.g., the ‘wet’ form of macular degeneration) and therefore it need not be surprising that an instance of optic neuritis in someone living with MS might become more susceptible to Charles Bonnet syndrome.

There is very little literature when it comes to descriptions of visual hallucinations/phantom imagery in MS patients. Rather than this demonstrating the rarity of such visual phenomena, it may well be more a function of three factors:

  • Research neglect
  • Clinical neglect (many physicians are unaware of, or failing to screen for, Charles Bonnet syndrome)
  • Patient silence (patient reluctance to disclose their unusual visual experiences)

Note that vision loss due to optic neuritis in multiple sclerosis patients can be a temporary situation. Medical treatment often leads to a restoration of vision and the resolution of Charles Bonnet syndrome.

Charles Bonnet syndrome and Ophthalmic (eye) procedures

This is perhaps the least known area of Charles Bonnet syndrome risk. Whilst it is understood that various eye diseases can lead to Charles Bonnet syndrome, it is not well known that Charles Bonnet syndrome can occur after a variety of eye procedures and treatments.

The range of eye procedures includes:

  • Avastin treatment for the ‘wet’ form of macular degeneration 7)
  • Macular hole surgery
  • Laser Peripheral Iridotomy (LPI) for (angle-closure) glaucoma
  • Alphagan eye drops for glaucoma
  • Enucleation (eye removal) and even
  • Simple eye patching.

Avastin treatments are often successfully performed without incident but Charles Bonnet syndrome can be an unexpected consequence of the procedure. In patients who received the Avastin (injection) treatment and Charles Bonnet syndrome ensued, their symptoms began within hours to days of the treatment. The vast majority of them had experienced no Charles Bonnet syndrome prior to the procedure. In one instance where a patient had experienced Charles Bonnet syndrome prior to the injection, it was found that after the Avastin treatment their Charles Bonnet syndrome symptoms increased in frequency.

In cases of narrow-angle or angle-closure glaucoma, often laser peripheral iridotomy is employed.Laser Peripheral Iridotomy essentially involves a laser beam creating a hole at the base of the iris to improve fluid drainage. It is thereby hoped that this will lead to a lowering of eye pressure.

Eye patching is often a routine medical procedure used after various forms of (eye) surgery and also in emergency departments. There are many reported instances of Charles Bonnet syndrome beginning suddenly after patching of the eye. Often, once the eye patch is removed, the Charles Bonnet syndrome clears up within a couple of days.

The principal concern is that patients are not being forewarned that Charles Bonnet syndrome is a possible side-effect of these types of procedures. Charles Bonnet syndromeF believes that patients have the right to be forewarned that complications such as Charles Bonnet syndrome can arise from such recommended procedures. In the lead up to such eye procedures, pre-warning of the possibility of Charles Bonnet syndrome is not only a client’s right but would in many instances reduce anxiety and concern if Charles Bonnet syndrome later develops.

Note that the lifespan of Charles Bonnet syndrome in some of these above instances is short-lived. That is, in cases of Charles Bonnet syndrome caused by one of the above procedures, the symptoms can sometimes be temporary (or reversible) once the strong, initial effects of the treatment wear off or the relevant treatment is stopped.

Charles Bonnet syndrome prevention

It’s not certain why some people experience phantom images but others don’t.

You cannot prevent Charles Bonnet syndrome from developing, but you may notice a pattern of triggers that help you manage the condition. Poor lighting, early mornings, late afternoons, night time, being at home and being tired can all be triggers. If you notice a pattern, you may be able to do something about it.

Charles Bonnet syndrome symptoms

Hallucinations associated with Charles Bonnet syndrome can be simple, non-formed images such as lines, light flashes, patterns, or geometric shapes. It’s common to see geometric patterns and lines with Charles Bonnet syndrome. Complicated images of people and places are common too. People with Charles Bonnet syndrome report seeing pictures of animals, plants, buildings, day-to-day objects and even entire landscapes.

Images can be beautiful, funny, strange or disturbing. They might float in the air, or appear on a wall or ceiling. They might be moving or still. They could be colorful or just black and white. They are usually not disturbing and do not involve other senses.

Most people who experience Charles Bonnet syndrome know the hallucinations are not real and do not have an underlying psychological disease or dementia 8).

Phantom images can be experienced for a few days or for many years. They can come and go, lasting for just a few seconds or continuing for many hours.

The timing and frequency of hallucinations can vary widely. The hallucinations tend to occur upon awakening. They usually last several minutes, but can be seconds or hours. Typically, there is a distinctive pattern to the timing and frequency of the hallucinations. The degree and complexity of the hallucinations also vary among individuals, but no association has been found between the complexity of the hallucinations and the severity of visual loss 9).

Associated symptoms depend upon the underlying disorder producing the visual loss. For example, strokes involving the visual pathways produce vision loss and sometimes other neurologic deficits, while macular degeneration and diabetic retinopathy produce loss of vision loss without neurologic deficits.

If you have Charles Bonnet syndrome, you do not have a mental problem; rather, you have a problem with your vision.

Talk to your doctor, an ophthalmologist, or a healthcare worker if you start seeing phantom images. They might not have heard about the condition, so you may have to tell them about it.

Charles Bonnet syndrome diagnosis

Diagnosing Charles Bonnet syndrome will involve taking a comprehensive medical history and an eye examination as a minimum. It may also involve a physical examination and tests for other causes of hallucinations.

About one third of people with significant vision loss are thought to experience phantom visions, but many people with Charles Bonnet syndrome never tell anyone about their symptoms and so they never get a diagnosis. They worry that people might think they are insane, or their doctor might not take them seriously.

Currently there is no agreed upon set of signs or symptoms for the Charles Bonnet syndrome diagnosis.

You might be diagnosed with Charles Bonnet syndrome if you:

  • have vision impairment
  • have seen a complex visual hallucination or phantom images recently
  • know what you saw was not real (i.e., no delusions)
  • are not mentally ill
  • do not have hallucinations involving other senses, such as your hearing. The images are solely visual (i.e., they cannot be heard, smelled, tasted, felt or touched)
  • have no noticeable issues with thinking or memory.

Charles Bonnet syndrome treatment

While there is currently no single treatment that is effective for all cases of Charles Bonnet syndrome, there are steps that patients can take that might have a positive effect:

  • Optimal eye care and regular visits to the ophthalmologist
  • Low vision aids to help maximize any existing vision
  • Avoidance of conditions known to aggravate Charles Bonnet syndrome such as stress, anxiety, social isolation, and sensory deprivation
  • Reassurance that the hallucinated images are benign and that treatment is an option
  • Medications including olanzapine, quetiapine, carbamazepine, clonazepam, and donepezil
  • Certain rapid eye movements or blinking to help suppress the hallucination
  • Repetitive transcranial magnetic stimulation

Charles Bonnet syndrome treatment options

Whilst there is presently no one single treatment that is effective in most cases, there are a range of options available and any one of these can have a positive effect 10).

Visual: Medical

Optimal eye care is strongly recommended.

  • Ongoing visits to your eye specialist is advised to ensure monitoring of one’s existing eye condition(s).
  • Relevant surgical procedures which improve vision have been known to resolve Charles Bonnet syndrome (e.g., removal of cataract).

Visual: Low Vision services

  • Maximizing existing vision through appropriate visual aids and localized lighting can also be beneficial.

There are documented cases of reduced – even resolved – Charles Bonnet syndrome simply by the provision of improved spectacles/magnifiers, reducing glare or altering one’s home lighting. Contact your local low-vision rehabilitation service provider for assistance with this matter.

Behavioral

Challenging standard lifestyle habits can be beneficial. For example, if Charles Bonnet syndrome symptoms typically occur while seated, try standing up. If they occur indoors, spend time outside. If the room is dimly lit, introduce lighting or vice versa. Blinking and rapid eye scanning techniques have also sometimes been found to be effective.

Sensory deprivation appears to be a crucial factor in Charles Bonnet syndrome. Visual input reaching the brain is significantly reduced due to vision loss. On top of this, many Charles Bonnet syndrome-affected persons are living lifestyles where they are further deprived of sensory stimulation. This includes rarely venturing outdoors, reduced social encounters or sitting alone in a living room that is dimly lit.

Opportunities to stimulate the senses is recommended

This could include: listening to talking books, engaging with others, playing music, undertaking some creative task, physical exercise, communing with nature or some tactile activity (e.g., knitting, gardening or even tapping the table). All these types of activities stimulate the brain and in doing so, may reduce the likelihood of Charles Bonnet syndrome.

Social isolation

Social isolation has been mentioned as a predisposing factor in Charles Bonnet syndrome. Attempts to counter isolation and engage people in social opportunities needs to be encouraged. This could be specifically through a Charles Bonnet syndrome self help group and/or general opportunities to socialize with others. If the person is home-bound, then visitors to the home or use of telephone/Skype services could also be beneficial.

Stress or anxiety tends to aggravate Charles Bonnet syndrome. That is, phantom images can become more pronounced or frequent when one is stressed.

Consider (re-) incorporating healthy behaviors/activities into your daily life that can induce a sense of calm or relaxation.

This could include:

  • movement to music,
  • hydrotherapy,
  • an (re-) introduced hobby or
  • creative endeavor.

Psycho-social

Understanding what one is dealing with

The initial experience of Charles Bonnet syndrome can be one of great fear and anxiety. When such strange visual things start happening, many naturally fear the worst. Perhaps the most commonly expressed thought is: “Am I losing my mind?” It is this understandable concern that often terrifies the affected person. As a result, up to 65% of all people living with Charles Bonnet syndrome never mention their symptoms to anyone. This means many suffer in silence – and sometimes for years on end.

What you know is that once an alternate explanation is provided to account for your strange visual experiences, about two thirds (67%) will feel almost immediate relief. Reassurance of the benign nature of the phantom images can be enormously liberating for the Charles Bonnet syndrome-affected person.

What can help put the person at ease includes:

  • An explanation of Charles Bonnet Syndrome
  • Supplying a medical name for their symptoms that is not associated with mental (or memory) disturbance
  • Openly discussing the issue
  • Being supportive, empathic and non-judgmental

These factors often allow people to feel comfortable enough to disclose their Charles Bonnet syndrome experiences. Truly understanding what one is dealing with often helps dissolve fear and openly talking with loved ones can remove the associated stigma and isolation.

Adjustment to vision loss

Sometimes people who have lost sight can struggle to adjust to their new situation. Everyday tasks that were once straightforward can become quite confronting and taxing. Certain activities suddenly become out of reach (eg. driving, reading, fine detail tasks). All this can have a profound effect upon the person in terms of how they view themselves and their place in the world. Exploring suitable outlets to make sense of all these changes in life circumstances can be beneficial. Ask your eye specialist or low vision rehabilitation service provider about what services are available in your local area. They may be offered at little or no cost.

Managing Charles Bonnet syndrome images

Consider trying to relate to, or engage with, the images differently. Reacting to the phantom images in habitual ways (e.g., fear, annoyance, frustration) can lock one into the experiences. Attempt to develop fresh ways to respond to the imagery.

Pharmacological

In instances where none of the above is found to be of assistance, pharmacological treatment could be explored. There have been numerous instances of total relief from Charles Bonnet syndrome as a result of prescribed medication. Having said that, it also needs to be noted that current medications used to treat Charles Bonnet syndrome include anticonvulsant and antipsychotic drugs. Whether these are the optimal treatment for Charles Bonnet syndrome remains a matter of conjecture.

Any of the following outcomes is possible from such prescribed medications:

  • Rapidly resolves Charles Bonnet syndrome
  • Has no effect on Charles Bonnet syndrome
  • Actually makes the Charles Bonnet syndrome symptoms worse or
  • Leads to unforeseen side effects.

Presently, there is no pharmaceutical drug that has been found to be effective in most, let alone all, cases. Therefore, exercising caution with this option is advisable.

For those keen to explore a prescribed medication, please ensure your medical practitioner presents you with the possible pros and cons of this approach so an informed decision can be made.

Electromagnetic

A more recent mode of treatment is known as repetitive transcranial magnetic stimulation (rTMS). It’s quite a mouthful to read but is a relatively harmless procedure which attempts to modulate brain activity. This procedure currently has wide application including treating depression, stroke rehabilitation and pain management.

It principally involves the use of an electromagnetic coil placed over a specific region of the head, which (depending on the specific condition) endeavors to either increase or decrease brain cell activity in that region.

Modern brain imaging equipment tend to indicate that the visual region of the brain in Charles Bonnet syndrome-affected persons is over-active (especially during the experience of Charles Bonnet syndrome imagery). There is preliminary evidence suggesting that the application of a low frequency (1 Hz) to this area can reduce brain activity. This ‘dampening’ of brain activity can lead to a reduction in, or resolution of, Charles Bonnet syndrome imagery. Early studies suggest that these effects can last up to a week beyond the stimulation period.

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