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 Table of Contents  
CASE REPORT
Year : 2022  |  Volume : 60  |  Issue : 2  |  Page : 186-188

Indirect Traumatic Optic Neuropathy with Associated Charles Bonnet Syndrome


1 Department of Ophthalmology, Westmead Hospital, Sydney, Australia
2 Department of Neuro Ophthalmology, Arunodaya Deseret Eye Hospital, Gurgaon, Haryana, India

Date of Submission20-Mar-2021
Date of Acceptance01-Oct-2021
Date of Web Publication30-Jun-2022

Correspondence Address:
Aditya Sethi
Department of Pediatric Ophthalmology and Neuro Ophthalmology, Arunodaya Deseret Eye Hospital, Sector 55, Gurgaon, Haryana
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/tjosr.tjosr_28_21

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  Abstract 


We report a case of an 84-year-old female who presented following a fall from standing height. There was immediate loss of vision in the right eye. On day 3 of admission, the patient described seeing hallucinations in the right eye. She described seeing children playing in the garden while sitting in the hospital bed. She was found to have an indirect traumatic optic neuropathy with an associated Charles Bonnet syndrome. The patient underwent conservative management and on 2 weeks follow-up her right eye vision improved to hand motions. To our knowledge, there is no reported case of this kind in the literature.

Keywords: Charles bonnet syndrome, indirect traumatic optic neuropathy, trauma, traumatic optic neuropathy


How to cite this article:
Girgis S, Sethi A, Sethi S, Sethi V, Sethi R, Sethi A. Indirect Traumatic Optic Neuropathy with Associated Charles Bonnet Syndrome. TNOA J Ophthalmic Sci Res 2022;60:186-8

How to cite this URL:
Girgis S, Sethi A, Sethi S, Sethi V, Sethi R, Sethi A. Indirect Traumatic Optic Neuropathy with Associated Charles Bonnet Syndrome. TNOA J Ophthalmic Sci Res [serial online] 2022 [cited 2022 Nov 30];60:186-8. Available from: https://www.tnoajosr.com/text.asp?2022/60/2/186/349522




  Introduction Top


Traumatic optic neuropathy (TON) is defined as a condition in which there is acute injury to the optic nerve from direct or indirect trauma resulting in vision loss. Charles Bonnet syndrome is defined as visual hallucinations in a patient without mental illness.[1]

We report a case of a patient who presented following a fall from standing height and was found to have an indirect TON with an associated Charles Bonnet syndrome. To our knowledge, there is no reported case of this kind in the literature.


  Case Report Top


An 84-year-old female was referred after falling while at the shopping centre. Her daughter had witnessed the fall and reported that the patient had a head strike and a single vomit. The patient had a past medical history of atrial fibrillation and hypertension and was taking aspirin and lercanidipine. The patient lived alone at home, mobilized independently and was independent of her activities of daily living.

The injuries sustained on impact were immediate loss of vision in the right eye, a right lateral wall orbital fracture, multiple facial fractures, a small amount of subarachnoid hemorrhage and pneumocephalus. Trauma surgery, neurosurgery, maxillofacial surgery, and ophthalmology teams were involved in the patient's care.

On presentation, the examination on the right eye demonstrated a visual acuity of light perception and a relative afferent pupillary defect with 270° of subconjunctival haemorrhage. The intraocular pressure was 7 mmHg, the ocular movements were intact in the cardinal directions and the fundus was unremarkable in the right eye. The left eye had a visual acuity of 6/18 with an intraocular pressure of 10 mmHg and an otherwise normal slit-lamp examination.

The patient's computerized tomography facial bones demonstrated a right lateral orbital wall fracture [Figure 1], on reporting it was deemed that the fracture was not impinging on the optic nerve. A magnetic resonance imaging (MRI) with orbital views was then performed to find a cause for the vision loss and an incidental right carotid-cavernous fistula (CCF) was found [Figure 2]. Interventional Neuroradiologist subsequently performed a digital subtraction angiography, which reported that the CCF was not contributing to the vision loss and was likely long standing. Significantly, the MRI demonstrated hyperintensity at the intra-canalicular portion of the optic nerve [Figure 3] and a diagnosis of Indirect TON was made.
Figure 1: Computerized tomography facial bones demonstrate a fracture in the lateral wall of the orbit with no impingement on the right optic nerve

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Figure 2: Magnetic resonance imaging brain demonstrated a right carotid cavernous fistula

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Figure 3: Magnetic resonance imaging with orbital views demonstrated hyperintensity of the intra-canalicular portion of the right optic nerve

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On day 3 of admission, the patient described seeing hallucinations in the right eye. She described seeing children playing in the garden while sitting in the hospital bed. The neurologist was contacted and in the context of light perception vision in the right eye and no mental health disease, a diagnosis of Charles Bonnet Syndrome was made. The patient underwent conservative management and on 2 weeks follow-up her right eye vision improved to hand movements.


  Discussion Top


The mechanism of optic nerve injury in Indirect TON has been the topic of much discussion. The mechanisms of Direct TON include optic nerve avulsion, optic nerve transection from an orbital or midfacial fracture, optic nerve sheath haemorrhage and orbital haemorrhage.[2] In Indirect TON, there are two mechanisms that are described in the literature to explain vision loss. One being the shearing injury of the optic nerve axons, on sudden deceleration of the skull, the eye continues forward and the optic nerve axons are stretched and shear, causing optic nerve damage.[3] Second, when there is a traumatic event, there is optic nerve swelling, the increased intraluminal pressure in the context of a fixed bony space of the optic canal, causes secondary ischaemic of the optic nerve.[4] The clinical features of TON are sudden vision loss and a relative afferent pupillary defect. The extra-ocular muscles are intact, the intraocular pressures are normal, and the fundus is unremarkable.[5]

The literature describes three ways to manage indirect TON: conservative management, surgical decompression and corticosteroids. International optic nerve trauma study[6] demonstrated that visual acuity increased by three or more lines in 32% of the patients that underwent surgery, 57% of that had conservative management and 52% of that had corticosteroids. This established that there was no statistically significant improvement in visual acuity when the patient underwent conservative management when compared to surgery or corticosteroids.[6]

The specific cause of hallucinations in Charles Bonnet syndrome is unknown. However, the literature attributes it to deafferentation. Deafferentation is defined as a lack of visual input into the brain, resulting in a release phenomenon.[7],[8] This is analogous to the phantom limb symptoms in amputee patients. One study established the deafferentation theory by demonstrating that of 13 normally sighted patients who were blind folded for 5 days, ten patients reported hallucinations after an average of just 1 day.[9]


  Conclusion Top


This case demonstrates that Charles Bonnet syndrome can be associated with indirect TON in the context of low impact trauma. These patients have poor visual prognosis[10] and should be referred to the appropriate local services.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Self-funding.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Jan T, Del Castillo J. Visual hallucinations: Charles bonnet syndrome. West J Emerg Med 2012;13:544-7.  Back to cited text no. 1
    
2.
Sarkies N. Traumatic optic neuropathy. Eye (Lond) 2004;18:1122-5.  Back to cited text no. 2
    
3.
Anderson RL, Panje WR, Gross CE. Optic nerve blindness following blunt forehead trauma. Ophthalmology 1982;89:445-55.  Back to cited text no. 3
    
4.
Yu-Wai-Man P. Traumatic optic neuropathy – Clinical features and management issues. Taiwan J Ophthalmol 2015;5:3-8.  Back to cited text no. 4
[PUBMED]  [Full text]  
5.
Miller NR, Walsh FB, Hoyt WF, editors. Walsh and Hoyt's clinical neuro-ophthalmology, vol. 2. 6th ed. Baltimore: Lippincott Williams & Wilkins; 2005.  Back to cited text no. 5
    
6.
Levin LA, Beck RW, Joseph MP, Seiff S, Kraker R. The treatment of traumatic optic neuropathy: The International Optic Nerve Trauma Study. Ophthalmology 1999;106:1268-77.  Back to cited text no. 6
    
7.
Jackson ML, Ferencz J. Cases: Charles Bonnet syndrome: Visual loss and hallucinations. CMAJ 2009;181:175-6.  Back to cited text no. 7
    
8.
Fernandez A, Lichtshein G, Vieweg WV. The Charles Bonnet syndrome: A review. J Nerv Ment Dis 1997;185:195-200.  Back to cited text no. 8
    
9.
Merabet LB, Maguire D, Warde A, Alterescu K, Stickgold R, Pascual-Leone A. Visual hallucinations during prolonged blindfolding in sighted subjects. J Neuroophthalmol 2004;24:109-13.  Back to cited text no. 9
    
10.
Carta A, Ferrigno L, Salvo M, Bianchi-Marzoli S, Boschi A, Carta F. Visual prognosis after indirect traumatic optic neuropathy. J Neurol Neurosurg Psychiatry 2003;74:246-8.  Back to cited text no. 10
    


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  [Figure 1], [Figure 2], [Figure 3]



 

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