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Journal of Glaucoma:
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Charles Bonnet Syndrome in Glaucoma Patients With Low Vision

Nesher, Ronit MD*; Nesher, Gideon MD†; Epstein, Esther MD*; Assia, Ehud MD*

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*Department of Ophthalmology, Sapir Medical Center, Kfar Saba, Israel; and Department of Internal Medicine, Shaare Zedek Medical Center, Jerusalem, Israel

Received February 20, 2001; accepted for publication June 13, 2001.

Address correspondence and reprint requests to Ronit Nesher, MD, Director of Glaucoma Service, Department of Ophthalmology, Sapir Medical Center, Kfar Saba, 44261 Israel.

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Purpose: To characterize the nature and frequency of Charles Bonnet syndrome in glaucoma patients with low vision.

Patients and Methods: All patients attending the glaucoma clinic during a period of 10 months who had visual acuity of 20/80 or less in both eyes were included in this study. Each patient was questioned about the occurrence of visual hallucinations. Those who responded positively had a thorough interview relating to the characteristics of the hallucinations. Medical history and social history were taken, followed by a complete ocular examination.

Results: Eighty-nine patients met the inclusion criteria. Eleven patients (12.3%), eight men and three women, admitted to having experienced visual hallucinations. Except for one case, the patients did not disclose this experience previously. Eight patients had one repeatable hallucination, and three patients experienced more than one sight. The visions were usually sharp, and the figures were occasionally incomplete. Most hallucinations were chromatic. Frequency of hallucinations varied between daily and weekly, and duration was mostly a few minutes. In addition to glaucoma, nine of the eleven patients had other ocular findings that could have contributed to the reduction of vision.

Conclusion: Visual hallucinations are not rare in glaucoma patients with low vision. Patients tend to conceal their experience of visual hallucinations, but a discussion of these phenomena with the patient and assurance of their harmless nature will reduce his or her anxiety and concerns.

The eponym Charles Bonnet syndrome (CBS) refers to the occurrence of formed visual hallucinations in older persons with normal cognition and insight. In 1760, the Swiss naturalist first described the syndrome in his grandfather, who had dense cataracts. Charles Bonnet syndrome has since been described in association with various pathologies leading to deterioration of vision at all levels of the visual system, such as in ocular pathology (e.g., cataract 1 and age-related maculopathy 2–4), optic nerve pathology in glaucoma 5,6 and temporal arteritis, 7 or secondary to pituitary tumor 8 and cortical damage. 9

The prevalence of CBS associated with these ocular pathologies is not clear. Several studies have reported CBS to be rather prevalent (approximately 12% to 13%) in patients with age-related macular degeneration. 2,4 Glaucoma may also lead to severe deterioration in vision, therefore one would expect to frequently encounter CBS among patients with glaucoma. However, aside from isolated descriptions of glaucoma patients with visual hallucinations, 5,6 this phenomenon is not well documented, and its prevalence is unknown.

We thus sought to study the prevalence of CBS in glaucoma patients with decreased vision who were attending an outpatient clinic in a tertiary care medical center, and to characterize the nature of these phenomena.

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The population screened consisted of patients visiting the Glaucoma Clinic at the Department of Ophthalmology, Sapir Medical Center, during a period of 10 months. All patients with visual acuity of 20/80 or less in both eyes were included in this cross-sectional study. Each patient was questioned about whether he or she had experienced the occurrence of certain formed sights that were unreal. Those who responded positively were asked to describe their experiences in detail. Patients were included in the study only when the interviewer was convinced that the sight perceived by the patient was not a distorted figure, an entoptic phenomenon, a dream, or an unclear shadow of an actual object.

A thorough interview was then carried out relating the characteristics of the hallucination. The size, color, clearness, state of motion, content, frequency of appearance and duration, and area of appearance in the visual field were all documented. Data were collected regarding age, sex, ethnic origin, level of education, living situation, medical history, neurologic and psychiatric history, and substance abuse. The cognitive status of the patients was crudely estimated by an abbreviated Mini-Mental test. 10 Each patient underwent a complete ocular examination that included Snellen visual acuity measurement, applanation tonometry, slit lamp examination of the anterior segment, and a dilated fundus examination.

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Eighty-nine patients met the inclusion criteria. Eleven patients (12.3%) admitted to having experienced visual hallucinations, and their characteristics are described in Table 1. Eight of these patients were male and three patients were female, and the mean age was 74 years (range, 60–96 years). The number of years of formal education varied from none to 15 years (mean, 7 years). None of the patients was taking a medication with hallucinatory potential. Except for one patient who was living in a nursing home, all patients were living either with a spouse (eight patients) or their family (two patients). Although almost all patients lived with a spouse or family member and half of patients experienced these hallucinations over a period of 1 year or more, only one patient (patient 11) had previously shared this experience of visual hallucinations with another person. In fact, when the patients were questioned about this experience, often the spouse that was present in the room immediately rejected such a possibility and was surprised to hear differently. However, most patients seemed to be relieved once they could finally share this experience without feeling ashamed and insecure about it.

Table 1
Table 1
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The type of glaucoma and the additional relevant ocular findings for each patient are elaborated in Table 2. Except for two patients, all had at least one additional major ocular finding that could have contributed to the reduction of vision. Four patients had cataracts and three patients had suffered from central vein occlusion. A maculopathy was present in five eyes. Other vision-reducing findings were anterior ischemic optic neuropathy in one eye and a corneal opacity in another.

Table 2
Table 2
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All patients were aware of the unreal nature of their hallucinations and rejected the possibility that they had misinterpreted a blurred image because of low vision. The contents of the visual hallucinations of each patient are described in Table 3. Though most patients had one repeatable sight, three experienced more than one sight. Patient 1 had four different hallucinations, each of which he was able to describe in detail. Although the visions were sharp for most patients, the figures were not always complete. Patient 1 saw only the head of an old man, patient 3 noted that the woman's face was blurred, and patient 5 described only the upper part of the body of the people that he saw. In some cases the sight was still, whereas in others the figures or objects were moving. However, in most cases there was no interaction between the vision and the patient except for two patients. Patient 3 described a vision of a woman dancing in front of him and approaching him fondly (to the dismay of his wife), and patient 9 saw a balloon moving away from him when climbing the stairs.

Table 3
Table 3
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The size, color, frequency, and duration of the hallucinations are described in Table 4. The frequency of the hallucinations varied between daily and weekly, though three patients had a single episode. The figures and objects seen by the patients were not always of normal size. Some described abnormally large figures whereas others noted abnormally small, even “dwarf-like” figures. Although most hallucinations were chromatic, some were monochromatic or achromatic. For most patients the length of time of a single hallucination was estimated as 1 or 2 minutes. One patient estimated the time in seconds, and only one patient claimed that the vision lasted 30 to 60 minutes.

Table 4
Table 4
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Twelve percent of our glaucoma patients with low vision admitted that they had experienced visual hallucinations. These results are in agreement with the report of an 11% prevalence of CBS among patients attending low vision clinics, 5 and a prevalence of 12% and 13% among patients with age-related macular degeneration 2,4 screened for visual hallucinations.

Formed visual hallucinations are not rare among patients with vision abnormalities. However, reports of their occurrence in the ophthalmologic literature are scarce. 4,11,12 Presumably, many of the patients are referred to psychogeriatric units for evaluation. Studies discussing CBS relate to patients recruited at these clinics, 13 and are published in neurologic, 14 geriatric, 15 and psychiatric 16 journals. Even studies surveying patients with low vision who were recruited in ophthalmology departments have been published in psychiatric literature 5,17; thus, many ophthalmologists are unaware of the relatively high prevalence of this phenomena among their patients with low vision.

Several neurologic diseases such as epilepsy, 18 Parkinsons disease, 19 and dementia 20 have been associated with visual hallucinations, but none of these was detected in our patients. Likewise, cerebral strokes have been associated with visual hallucinations. 9 Among our patients, only patient 3 suffered repeated strokes and an association between that occurrence and the hallucinations can be argued in that particular case.

Several ocular pathologies have also been described in association with visual hallucinations. 1–6 In our group of patients, five had macular pathology in addition to advanced glaucoma. It is impossible to estimate the relative contribution of the maculopathy to the overall low vision state in these patients. Dense cataracts were present in two patients. In one of these patients (patient 9), hallucinations ceased after the removal of the cataract and improvement in visual acuity.

An impaired cognition should be excluded before making a diagnosis of CBS. Many studies have incorporated psychologic tests into their routine evaluation of patients with complex visual hallucinations. 15 In our study we used an abbreviated form of the Mini-Mental State Examination. 10 None of our patients had impaired cognition.

The content and characteristics of the hallucinations in CBS were described by Schultz et al. 21 In their 60 patients, visual hallucinations were present for a few seconds and no motion occurred. The images were sharp, appeared and vanished suddenly, and were only present when the eyelids were open. In our group of patients, hallucinations were present for a longer period and images were in motion in some cases.

The pathogenesis of visual hallucinations in mentally healthy persons is unclear. Sensory deprivation has been implicated as a possible cause. 12 The reaction of the visual cortex to the sudden or progressive lack of visual stimulation results in release phenomena (i.e., the perception of nonexisting images). 22 Sensory deprivation is thought to be more prevalent in patients with decreased social contacts and low extroversion. 23 Thus, living alone has been implicated as a predisposing factor for the development of visual hallucinations. This factor was not relevant in our group of eleven patients because 10 were living with a spouse or family member.

An alternative approach to explaining the pathogenesis of CBS has regarded the condition as an irritative (ictal) phenomenon 18 secondary to epilepsy or cerebral space-occupying lesions. However, none of our patients had evidence of such lesions or a history of epilepsy.

Recently it has been suggested that different abnormal perceptions originate in different specialized cortical areas. 24,25 The functional magnetic resonance imaging has been instrumental in investigating this association. 26 In particular, the technology associated the ventral extrastriate region of the human brain with color perception and suggested that in some patients with CBS, a phasic increase in activity in this area was associated with chromatic hallucinations often reported as vivid. 27

Treatment for CBS is rarely needed unless patients are disturbed by the frequent occurrence of sights. Treatment with classic neuroleptics, antidepressants, or benzodiazepines is generally ineffective. Successful therapy has been observed with melperone 28 and carbamazepine. 29 Recently there have been reports of successful elimination of the hallucinations with cisapride, a potent 5-hydroxytryptophan antagonist. 30 In our group of patients, the occurrence of hallucinations was of no concern after the physicians explained their source and nature. Thus, no patient required treatment.

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Our study suggests that CBS is not rare in glaucoma patients with low vision. Because patients tend to conceal this phenomena and rarely consult their ophthalmologists about these experiences, we recommend that all patients with low vision be questioned about occurrence of visual hallucinations. Undoubtedly, a discussion of these phenomena with the patients and assurance of their harmless nature will reduce the anxiety and shame associated with having visual hallucinations.

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1. Berrios GE, Brook P. The Charles Bonnet syndrome and the problem of visual perceptual disorders in the elderly. Age Aging W 1982; 11:17–23.

2. Holroyd S, Rabins PV, Finkelstein D, et al. Visual hallucinations in patients with macular degeneration. Am J Psychiatry 1992; 149:170–6

3. Abraham HD. Visual hallucinations in macular degeneration. Am J Psychiatry 1993; 150:1758.

4. Brown GC, Murphy RP. Visual symptoms associated with choroidal neovascularization. Photopsias and the Charles Bonnet syndrome. Arch Ophthalmol 1992; 110:1251–6.

5. Teunisse RJ, Cruysberg JR, Verbeek A, et al. The Charles Bonnet syndrome: a large prospective study in the Netherlands. A study of the prevalence of the Charles Bonnet syndrome and associated factors in 500 patients attending the university department of ophthalmology at Nijmegen. Br J Psychiatry 1995; 16:254–7

6. Lepore FE. Spontaneous visual phenomena with visual loss: 104 patients with lesions of retinal and neural afferent pathways. Neurology 1990; 40:444–7.

7. Sonnenblick M, Nesher R, Rozenman Y, et al. Charles Bonnet syndrome in temporal arteritis. J Rheumatol 1995; 22:1596–7.

8. Ram Z, Findler G, Gutman I, et al. Visual hallucinations associated with pituitary adenoma. Neurosurgery 1987; 20:292–6.

9. Kolmel HM. Complex hallucinations in the hemianopic field. J Neurol Neurosurg Psychiatry 1985; 48:29–38.

10. Koenig HG. An abbreviated Mini-Mental State Exam for medically ill older adults. J Am Geriatr Soc 1996; 44:215–16.

11. Nadarajah J. Visual hallucinations and macular degeneration: an example of the Charles Bonnet syndrome. Aust N Z J Ophthalmol 1998; 26:63–5.

12. Siatkowski RM, Zimmer B, Rosenberg PR. The Charles Bonnet syndrome. Visual perceptive dysfunction in sensory deprivation. J Clin Neuroophthalmol 1990; 10:215–8.

13. Norton L, Munir M. Visual perceptual disorders resembling the Charles Bonnet syndrome. A study of 434 consecutive patients referred to a psychogeriatric unit. Fam Pract 1987; 4:27–35.

14. Manford M, Andermann F. Complex visual hallucinations. Clinical and neurobiological insights. Brain 1998; 121:1819–40.

15. Pliskin NH, Kiolbasa TA, Towle VL et al. Charles Bonnet syndrome: an early marker of dementia? J Am Geriatr Soc 1996; 44:1055–61.

16. Fernandez A, Lichtshein G, Vieweg WV. The Charles Bonnet syndrome: a review. J Nerv Ment Dis 1997; 185:195–200.

17. Lalla D, Primeau F. Complex visual hallucinations in macular degeneration. Can J Psychiatry 1993; 38:584–6.

18. Sowa MV, Pituck S. Prolonged spontaneous complex visual hallucinations and illusions as ictal phenomena. Epilepsia 1989; 30:524–6.

19. Diederich NJ, Goetz CG, Raman R, et al. Poor visual discrimination and visual hallucinations in Parkinson's disease. Clin Neuropharmacol 1998; 21:289–95.

20. Schultz G. Melzack R. Visual hallucinations and mental state. A study of 14 Charles Bonnet syndrome hallucinators. J Nerv Ment Dis 1993; 181:639–43.

21. Schulz G, Needham W, Talyor R, et al. Properties of complex hallucinations associated with deficits in vision. Perception 1996; 25:715–26.

22. Cogan DG. Visual hallucinations as release phenomena. Graefe Arch Clin Exp Ophthalmol 1973; 188:139–45.

23. Teunisse RJ, Cruysberg JR, Hoefnagels WH, et al. Social and psychological characteristics of elderly visually handicapped patients with the Charles Bonnet syndrome. Compr Psychiatry 1999; 40:315–9.

24. Zeki S. Cerebral akinetopsia (visual motion blindness). A review. Brain 1991; 114:811–24.

25. McKeefry DJ, Zeki S. The position and topography of the human color center as revealed by functional magnetic resonance imaging. Brain 1997; 120:2229–42.

26. Howard R., David A, Woodruff P, et al. Seeing visual hallucinations with functional magnetic resonance imaging. Dement Geriatr Cogn Disord 1997; 8:73–7.

27. Ffytche DH, Howard RJ, Brammer MJ, et al. The anatomy of conscious vision: an fMRI study of visual hallucinations. Nat Neurosci 1998; 1: 738–42.

28. Batra A, Bartels M, Wormstall H. Therapeutic options in Charles Bonnet syndrome. Acta Psychiatr Scand 1997; 96:129–33.

29. Bhatia MS, Khastgir U, Malik SC. Charles Bonnet syndrome. Br J Psychiatry 1992; 161:409–10.

30. Ranen NG, Pasternak RE, Rovner BW. Cisapride in the treatment of visual hallucinations caused by vision loss: the Charles Bonnet syndrome. Am J Geriatr Psychiatry 1999; 7: 264–6.

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Sensory deprivation; Vision; Visual hallucinations

© 2001 Lippincott Williams & Wilkins, Inc.


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