Bedisha Biswas, B.Optom

Student, Pailan College of Management and Technology, MAKAUT, India


Visual hallucinations involve seeing things that are not there which is a sensory misperception in the absence of an actual external stimulus, experienced by patients. Do you ever wonder if these visual hallucinations are happening due to any visual or neurological problem?

Many people in the world are suffering from visual hallucinations but did not consult with their doctors out of fear and embarrassment, as hallucinations are associated with mental illness. Visual hallucinations may occur in neurological diseases, metabolic disorders, psychiatric conditions, Alzheimer’s, CBS, illicit drug use, delirium, and the use of certain medications.

Figure 1: Example of typical Phantom Vision Syndrome
(Created by Author)

What is Charles Bonnet Syndrome?

Charles Bonnet Syndrome (CBS) or ‘Phantom vision’ is a complicated condition where visual hallucinations occur due to damage in the visual pathway along with vision loss. Among patients attending ophthalmology clinics Worldwide, the incidence of CBS ranges from 0.4 to 14%. (1)

Visual hallucinations include flashing lights, people, faces, animals, landscapes, ballerinas, geometrical patterns, houses, coloured balls etc. No other sensory modalities were affected.(1,2)

Figure 2: How Charles Bonnet Syndrome affects the vision
(Picture Courtesy: [last accessed 17th Oct 2022, 17:45AEST])

No Age Limit

CBS can affect people of any age (mostly elderly people), having any visual pathologies where vision impairment occurred. One can have CBS if she/he has macular degeneration, diabetic retinopathy, glaucoma, hemianopia field loss or other retinal disorders etc. Visual hallucinations have not been noted by those with congenital blindness.


The exact aetiology of CBS is not clear. There are two hypotheses which are accepted as possible explanations for the pathogenesis of the CBS hallucinations.

Figure 3: Hypothesis of CBS
(Created by Author)

It’s assumed that a decrease in visual acuity due to resistance of visual information to the brain leads to CBS. Lack of visual data inflowing through the eyes, the brain tries to fill the void and recalls the preserved images or imagination for the patient to see, which causes the visual hallucinations of CBS.


There is no such test available to diagnose CBS. The diagnosis for CBD is generally made on the basis of the available medical history and  evaluating the other sources of visual hallucinations including mental stress or health problems, whether any medication is taken or not and other neurological (brain) problems.(3)


There are no such treatment options available to cure this condition. But we can manage this situation with some techniques to reinforce the condition for the patient to cope with their daily life.(4-6) Those are as followings –

  • Talk about the hallucination with the doctor, therapist or a family member or a friend.
  • Treating pathological eye disorders with appropriate medication and care.
  • Prescribing glasses with BCVA.
  • Special tints, antiglare glasses to enhance the visual quality.
  • Low Vision Aids (LVA) to decrease their sensory deprivation, thereby suppressing visual. hallucinations in CBS.
  • Eye exercises, like moving the eyes in an up-and-down or side-to-side motion, sometimes helps reduce the experiences of visual hallucinations as it engages the eyes and stimulates the brain.
  • Other things like changing environment, relaxing, or engaging with pets or some interesting activities sometimes help to reduce those episodes.

Figure 4: Management of CBS
(Picture Courtesy:[last accessed 17th Oct 2022, 17:45AEST])

Over time, the more one hallucinates, the more she/he will learn to manage them. Mostly, the hallucinations slow down considerably. (4)


Charles Bonnet syndrome is a rare clinical condition that is unmarked to many medical practitioners. In the elderly population, the clinician should be aware that CBS may be an early sign of dementia where necessary evaluation and treatment might be needed accordingly. Enhancing visual function, understanding the patient’s mental health, addressing social isolation, and initiating pharmacological therapy are all important options to consider for CBS patients.(5,6) If one have these kinds of symptoms, they should consult with an eye-care specialist for early evaluation, but not any wizard.



  1. Schadlu AP, Schadlu R, Shepherd III JB. Charles Bonnet syndrome: a review. Current opinion in ophthalmology. 2009 May 1;20(3):219-22.
  2. Voit M, Jerusik B, Chu J. Charles Bonnet Syndrome as Another Cause of Visual Hallucinations. Cureus. 2021 Jan 26;13(1).
  3. Teeple RC, Caplan JP, Stern TA. Visual hallucinations: differential diagnosis and treatment. Primary Care Companion to the Journal of Clinical Psychiatry. 2009;11(1):26.
  4. Prabhaharan B. Charle’s bonnet’s syndrome: Are medication necessary. TNNMC Journal of Medical & Surgical Nursing. 2021;9(2):43-4.
  5. Menon GJ, Rahman I, Menon SJ, Dutton GN. Complex visual hallucinations in the visually impaired: the Charles Bonnet Syndrome. Survey of ophthalmology. 2003 Jan 1;48(1):58-72.
  6. Eperjesi F, Akbarali N. Rehabilitation in Charles Bonnet syndrome: a review of treatment options. Clinical and Experimental Optometry. 2004 May 1;87(3):149-52.