Traumatic Globe Luxation With Chiasmal Avulsion

Background: To describe an unusual case of traumatic globe luxation with optic chiasmal avulsion and review the existing literature on this rare condition for further discussion of mechanisms, diagnosis, and management. Methods: Case report and review of existing case reports and case series identified through literature search. Results: A 28-year-old woman, with no previous medical history, had left globe luxation and optic chiasm avulsion after being stabbed directly into the left orbit with the use of the stiletto high heel of a shoe. Automated visual field testing detected a temporal hemianopia in the unaffected eye despite normal central visual acuity. Chiasmal avulsion was demonstrated by MRI. Conclusions: This case suggests that perimetry and MRI should always be considered in traumatic globe luxation to localize the site of injury. Temporal hemianopia in the fellow eye indicates a concomitant chiasmal injury.

Original Contribution Traumatic Globe Luxation With Chiasmal Avulsion Sandy Wenting Zhou, MD, MMed (Ophth), Audrey Yuan Ching Pang, MB BChir (Cambridge), MMed (Ophth), FAMS (Ophth), FRCOphth (London), Eugenie Wei Ting Poh, MBBS, MRCSEd, MMed (Ophth), FRCSEd (Ophth), FAMS (Ophth), Chee Fang Chin, MBChB, MMed, FRCSEd (Ophth), FAMS (Ophth) Background: To describe an unusual case of traumatic globe luxation with optic chiasmal avulsion and review the existing literature on this rare condition for further discussion of mechanisms, diagnosis, and management. Methods: Case report and review of existing case reports and case series identified through literature search. Results: A 28-year-old woman, with no previous medical history, had left globe luxation and optic chiasm avulsion after being stabbed directly into the left orbit with the use of the stiletto high heel of a shoe. Automated visual field testing detected a temporal hemianopia in the unaffected eye despite normal central visual acuity. Chiasmal avulsion was demonstrated by MRI. Conclusions: This case suggests that perimetry and MRI should always be considered in traumatic globe luxation to localize the site of injury. Temporal hemianopia in the fellow eye indicates a concomitant chiasmal injury. Journal of Neuro-Ophthalmology 2019;39:41-43 doi: 10.1097/WNO.0000000000000671 © 2018 by North American Neuro-Ophthalmology Society FIG. 1. Appearance of patient after she was assaulted. disinserted. No globe perforation was seen. The left pupil was dilated and nonreactive and left fundus appeared normal. Examination of the patient's right eye was normal. Computed tomography of the orbits showed severe proptosis of the left eye with a retrobulbar hematoma (Fig. 2). The medial and lateral rectus muscles were disinserted. The optic nerve appeared stretched, but avulsion A 28-year-old previously healthy woman was evaluated in the emergency department after being stabbed in her left orbit with a stiletto high heel of a shoe. She had no loss of consciousness or other injuries. Visual acuity was no light perception in the left eye and 20/20 in the right eye. There were full-thickness lacerations of the left upper and lower eyelids. The left eye was severely proptotic and luxated, with three quarters of the globe protruding out of the orbit (Fig. 1). The medial rectus was Department of Ophthalmology, Tan Tock Seng Hospital, National Healthcare Group Eye Institute, Singapore. The authors report no conflicts of interest. Address correspondence to Chee Fang Chin, Department of Ophthalmology, Tan Tock Seng Hospital, National Healthcare Group Eye Institute, 11 Jalan Tan Tock Seng, Singapore 308433; E-mail: [e-mail] Zhou et al: J Neuro-Ophthalmol 2019; 39: 41-43 FIG. 2. Axial computed tomography shows severe proptosis of the left eye with a retrobulbar hematoma. 41 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Original Contribution FIG. 3. Axial T2 MRI shows normal signal of the canalicular and prechiasmal right optic nerve (arrow). On the left, there is increased signal (arrowhead) indicating absence of optic nerve at its junction with the optic chiasm. could be identified. A left lateral canthotomy was performed to relieve pressure from the retrobulbar hemorrhage. MRI of the orbits revealed discontinuity of the left optic nerve just proximal to the optic chiasm (Fig. 3). Asymmetrical T2 signal changes were present at both ends of the left optic canal, suggesting presence of cerebrospinal fluid in the canal. This was consistent with complete avulsion of the left optic nerve. Before surgery, the patient noticed a visual field defect in her right eye. Visual acuity and color vision were intact in the right eye but confrontational visual field testing detected a temporal hemifield defect. Despite our best efforts, repositioning of the left eye into the orbit was unsuccessful, and the left eye was enucleated. Postoperatively, automated (Humphrey) visual field testing showed a temporal hemianopia in the right eye (Fig. 4A). After 3 days of intravenous methylprednisolone (1 g/day), repeat testing revealed a residual superotemporal defect (Fig. 4B). There was no change in the field defect at last follow-up. Traumatic globe luxation/enucleation generally is associated with optic nerve avulsion. The most common site of avulsion is the orbital apex (55%), followed by the anterior chiasm (33%) and the optic nerve head (11%) (1). In our patient, the optic nerve was torn at the chiasm. We postulate direct and indirect mechanisms of damage: 1) direct: shearing forces on the chiasm led to structural damage to the decussating fibers; and 2) indirect: traction caused edema and microvascular ischemia of the optic chiasm, interfering with the function of the crossing fibers. Reports with injuries similar to our patient are summarized in Table 1. FIG. 4. Automated visual fields performed at initial presentation (A) and 3 days following (B) treatment with intravenous methylprednisolone. 42 Zhou et al: J Neuro-Ophthalmol 2019; 39: 41-43 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Original Contribution TABLE 1. Reports of traumatic globe luxation with chiasmal injury Report/ Year Age/ Years Sex Mechanism Visual Acuity Arkin et al (2) 25 M Assault: Finger injury NLP Parmar et al (3) 24 M Assault: finger injury NLP Kotlus et al (4) 31 F Selfenucleation NLP Sean et al (5) 45 F Blunt trauma: Fell onto a mounted door stop NLP CT Findings MRI Findings Surgical Contralateral Eye, Treatment (VA & HVF or GVF) Repositioning Empty optic canal except for cuff of remaining dura of the optic nerve closely adherent to the periosteum Enucleation N/A Swelling of the left side of the chiasm Enucleation Subacute cortical Complete optic nerve avulsion 3 mm anterior infarction involving both cerebral to the optic chiasm; hemispheres with hyperintense signal gyriform signal surrounding the hyperintensity intracranial optic nerve N/A Enucleation Complete optic nerve avulsion; globe enucleation, retained retrobulbar foreign body Marked proptosis, and a severed optic nerve with its free end lying within the orbit VA: 20/20; GVF: Superotemporal wedge defect VA; 20/20 GVF: Complete temporal defect VA: LP VA: N/A AVF: Superotemporal defect AVF, automated visual field; CT, computed tomography; F, female; GVF, Goldmann visual field; HVF, Humphrey visual field; LP, light perception; M, male; N/A, not available; NLP, no light perception; VA, visual acuity. MRI remains the gold standard in evaluating the optic nerve and chiasm. If a chiasmal lesion is suspected, thinsection T1 and T2 scans with and without contrast should be obtained in the axial, coronal, and sagittal planes. Treatment of traumatic optic neuropathy is controversial; to date, there is no strong evidence supporting steroid treatment. Spontaneous improvement is also recognized. Yet following steroid therapy, our patient showed improvement, but it is debatable whether this was spontaneous or related to our treatment. STATEMENT OF AUTHORSHIP Category 1: a. Conception and design: C. F. Chin and S. W. Zhou; b. Acquisition of data: S. W. Zhou, A. Y. C. Pang, and E. W. T. Poh; c. Analysis and interpretation of data: S. W. Zhou and E. W. T. Poh. Category 2: a. Drafting the manuscript: S. W. Zhou and C. F. Chin; b. Revising it for intellectual content: S. W. Zhou and Zhou et al: J Neuro-Ophthalmol 2019; 39: 41-43 C. F. Chin. Category 3: a. Final approval of the completed manuscript: C. F. Chin. REFERENCES 1. Krauss H, Yee R, Foos R. Autoenucleation. Surv Ophthalmol. 1984;29:179-187. 2. Arkin MS, Rubin PA, Bilyk JR, Buchbinder B. Anterior chiasmal optic nerve avulsion. AJNR Am J Neuroradiol. 1996;17:1777- 1781. 3. Parmar B, Edmunds B, Plant G. Traumatic enucleation with chiasmal damage: magnetic resonance image findings and response to steroids. Br J Ophthalmol. 2002;86:1317-1318. 4. Kotlus BS, Lo MW. Subarachnoid haemorrhage and vasospastic stroke after self-enucleation. Ophthalmol Plast Reconstr Surg. 2007;23:425-427. 5. Paul S, Lucarelli MJ, Griepentrog GJ. Traumatic enucleation with chiasmal damage. Ophthalmology. 2017;124:767. 43 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.