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Show Clinical Correspondence Section Editors: Robert Avery, DO Karl C. Golnik, MD Caroline Froment, MD, PhD An-Guor Wang, MD Acute Onset of Charles Bonnet Syndrome After Unilateral Central Retinal Artery Occlusion in the Background of Tense Orbit Ourania Fydanaki, MD, PhD, Varajini Joganathan, MD, MSc C harles Bonnet is a well-known syndrome (CBS) in the ophthalmological community and includes visual hallucinations in patients with normal cognitive status and psychological and intellectual background (1). The patients understand the unreal nature of their hallucinations, which include a wide range from simple patterns to people, animals, and objects (1). It presents often in patients with bilateral low visual acuity (2), whereas macula pathology and glaucoma are among the most common ocular etiologies (1,2). We would like to share our observation and a learning opportunity about our patient: a 52-year-old patient with left orbital cellulitis secondarily a tooth extraction. Visual acuity on presentation was 6/6 in the right eye and light perception for the left eye, accompanied with left relative afferent pupillary defect and intraocular pressure of 45 mm Hg for the same eye. The patient was diagnosed with left orbital compartment syndrome, and urgent canthotomy and cantholysis was performed. According to urgent computed tomography (CT) of head and orbits, left maxilla and ethmoidal sinuses were occupied, and urgent drainage was performed on the same day. Dilated funduscopy revealed left central retinal artery occlusion (CRAO). The patient was hospitalized for 10 days for intravenous antibiotics accordingly. Twenty-four hours after the loss of vision of the left eye, while visual acuity remained stable to light perception, the patient reported weird circular patterns, like bubbles, seen with the left eye only. Within 48 hours, the patterns became more complex and the patient could see 4 figures and few cats around her, when the right eye was closed. No previous psychiatric history was recorded for the patient. The patient was aware that she was experiencing visual hallucinations. She was explained about the CBS and reassured about the benign nature of it. These symptoms lasted only for 3 days and there was no recurrence, while visual acuity remained stable to perception of light for the left eye. Central retinal artery occlusion is a rare cause of CBS and has been reported in previous cases (1,3). The time of Ophthalmology Department, University Hospital Southampton NHS Foundation Trust, Hampshire, United Kingdom. The authors report no conflicts of interest. Address correspondence to Ourania Fydanaki, MD, PhD, Department of Opthalmology, University Hospital Southampton NHS Foundation Trust, Tremona Road, Southampton, Hampshire SO16 6YD, Southampton, United Kingdom; E-mail: raniafida@yahoo.gr e356 presentation of CBS after CRAO is not defined and little evidence has been provided, with case reports only. Tan et al presented 2 cases of CRAO with acute presentation of CBS occurring 2 and 6 days after the vascular incidence (3). In our case, the Charles Bonnet symptoms started early and within 24 hours of the CRAO event. Τhe pathophysiology of CBS is not fully defined. It has been suggested that CBS risk is related more with the dynamic decrease of vision in sight-impaired patients or the acute decline of vision, rather than the low visual acuity itself (4). One of the most prevalent theories suggests that the acute visual impairment is a result of the hyperactivation of visualrelated cortex, due to changes in neurotransmission during the early recovery period (1,3,5). The above theory could explain our case, in which the recovery period was short, with only 3 days of symptoms, and the cessation of the visual hallucinations indicated the end of it. However, in previous CRAO cases, symptoms of 2–4 weeks’ duration were reported (3). In conclusion, we suggest that CBS can occur within the first 24 hours after a unilateral CRAO, even with normal visual acuity to the contralateral eye. The visual hallucination in these patients tends to be temporary and restricted to the recovery period. General ophthalmologists should be aware of the possible subsequent CBS in patients with CRAO, reassure their patients and their families about the nature of the visual hallucinations, and refer to appropriate specialists, such as eye clinic, low-vision aid service, or clinical psychologist, for further management if needed. REFERENCES 1. Pang L. Hallucinations experienced by visually impaired: Charles Bonnet Syndrome. Optom Vis Sci. 2016;93:1466–1478. 2. Teunisse RJ, Cruysberg JR, Verbeek A, Zitman FG. 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;166:254–257. 3. Tan CS, Sabel BA, Goh KY. Visual hallucinations during visual recovery after central retinal artery occlusion. Arch Neurol. 2006;63:598–600. 4. Shiraishi Y, Terao T, Ibi K, Nakamura J, Tawara A. Charles Bonnet syndrome and visual acuity—the involvement of dynamic or acute sensory deprivation. Eur Arch Psychiatry Clin Neurosci. 2004;254:362–364. 5. Nan L, Yanbin H, Jingping Z. Acute reversible Charles Bonnet Syndrome following eye patch placement. Neuroophthalmology. 2013;37:35–37. Fydanaki and Joganathan: J Neuro-Ophthalmol 2022; 42: e356 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. |
