Journal of Neuro-Ophthalmology, June 2015, Volume 35, Issue 2

Retracting Globe: Enophthalmos and Retraction Due to an Accessory Extraocular Muscle

Donald R. Pettit, PhD NASA Johnson Space Center, Houston, Texas The authors report no conflicts of interest. REFERENCES 1. Mader TH, Gibson CR, Pass AF, Lee AG, Killer HE, Hansen H-C, Dervay JP, Barratt MR, Tarver WJ, Sargsyan AE, Kramer LA, Riascos R, Bedi DG, Pettit DR. Optic disc edema in an astronaut after repeat long-duration space flight. J Neuroophthalmol. 2013;33:249-255. 2. Jacks AS, Miller NR. Spontaneous retinal venous pulsation: aetiology and significance. J Neurol Neurosurg Psychiatry. 2003;74:7-9. 3. Fry WE, Variations in the intraneural course of the central retinal vein. Arch Ophthalmol. 1930;4:180-187. 4. Fry WE. The pathology of papilloedema: an examination of forty eyes with special reference to compression of the central vein of the retina. Am J Ophthalmol. 1931;14:874-883. 5. Mader TH, Gibson CR, Pass AF, Kramer LA, Lee AG, Fogarty J, Tarver WJ, Dervay JP, Hamilton DR, Sargsyan A, Phillips JL, Tran D, Lipsky W, Choi J, Stern C, Kuyumjian R, Polk JD. Optic disc edema, globe flattening, choroidal fold, and hyperopic shifts observed in astronauts after long-duration space flight. Ophthalmology. 2011;118:2058-2069. Retracting Globe: Enophthalmos and Retraction Due to an Accessory Extraocular Muscle We read with interest the report of Liao and Hwang of an accessory lateral rectus muscle in a patient with normal ocular motility (1). Accessory extraocular muscles are rare anatomic anomalies. They may represent vestigial structures homologous to the retractor bulbi muscle in amphibians, reptiles, and lower mammals (2) or a distur-bance in mesodermal development of extraocular muscles (2-4). We recently evaluated a patient with an accessory extraocular muscle with clinical and radiologic findings dif-fering from the case of Liao and Hwang. A 26-year-old woman was referred for evaluation of right enophthalmos worse with eye movement present for 3 years and worsening since ptosis surgery 1 year ago. There was associated headache but no other visual or neurologic complaints. Visual acuity was 20/25 right eye and 20/20, left eye. There was limited abduction of the right eye, and the patient reported diplopia in right gaze. The right eye was 4-mm enophthalmic in primary position, and the enophthalmos increased to 7 mm in right superolateral gaze (Fig. 1). The rest of the examination was normal. Multidetector 2-mm axial noncontrast CT images were obtained with bone and soft tissue technique and coronal isovoxel reformatted images with the patient in primary position and right and left gaze (Fig. 2). Imaging sequen-ces showed a thin elongated structure isodense to normal extraocular muscle, extending from the annulus of Zinn to FIG. 1. Extraocular movements demonstrate right enophthalmos that increases with abduction and elevation of the right eye. Letters to the Editor: J Neuro-Ophthalmol 2015; 35: 226-231 227 Letters to the Editor Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. the posterior globe, inferior, and medial to the optic nerve insertion. On right gaze, the eyes were disconjugate with limited abduction of the right eye. On left gaze, the eyes maintained a conjugate position and the accessory extra-ocular muscle approximated the nasal aspect of the optic sheath. Given the clinical and neuroimaging findings, the patient was diagnosed with an accessory extraocular muscle. The prevalence of accessory extraocular muscles is un-known, but English-language PubMed search revealed 22 reported cases. Most accessory extraocular muscles arise from the orbital apex (14/22 cases) with others arising from an extraocular muscle. Half of that arise from the apex (7/14) insert onto the sclera of the posterior globe in varied locations: inferomedial (2 cases) (3,5), superolateral (2 cases) (1,6), inferior (1 case) (7), and inferolateral (2 cases) (4,8). Two patients had retraction of the globe (3,7), 3 had enoph-thalmos (4,6,9), and 1 was asymptomatic (1). In addition, all patients with accessory extraocular muscle attaching to the sclera had some component of restricted ocular motility, except the case reported by Liao and Hwang (1). There is not always a clear anatomic correlation between clinical and neuroimaging findings, although such was the case in our patient. Her marked enophthalmos was the greatest in right superolateral gaze, opposite to the infer-omedial insertion of the accessory extraocular muscle. In comparison, the other 2 cases of inferomedial insertion were associated with restricted elevation on abduction (5) and globe retraction with superior and inferior eye movement (3). In addition, the 2 cases of inferomedial insertion were associated with restricted elevation on abduction (5) and globe retraction with superior and inferior eye movement (3). In addition, the 2 cases of globe retraction associated with an accessory extraocular muscle showed differing radi-ology findings. One patient experienced globe retraction with adduction and the accessory muscle attached to the posterior sclera inferiorly (7). Retraction of the eye in the second pa-tient occurred with vertical eye movements and the accessory muscle attached to inferomedial posterior sclera (3). Strabismus is the most common indication for surgery and usually performed in patients with anterior scleral or direct extraocular muscle insertion of the accessory muscle. There are no reports of improvement in enophthalmos with eye muscle surgery. Cristy A. Ku, PhD Department of Ophthalmology, West Virginia University Eye Institute, Morgantown, West Virginia Christopher W. Bailey, DO Department of Radiology, West Virginia University, Morgantown, West Virginia FIG. 2. Noncontrast orbital computed tomography. Axial (A) and coronal (B) scans show the accessory extraocular muscle (arrow) located inferomedial to the optic nerve and extending from the orbital apex attaching to the sclera inferomedially. Axial images in right (C) and left (D) gaze reveal limited abduction of the right eye and increased right enophthalmos in right gaze. In (C) and (D), the white line extends from the medial to lateral orbital rim. 228 Letters to the Editor: J Neuro-Ophthalmol 2015; 35: 226-231 Letters to the Editor Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Thomas D. Roberts, MD Department of Radiology, West Virginia University, Morgantown, West Virginia Jeffery P. Hogg, MD Department of Radiology, West Virginia University, Morgantown, West Virginia Jennifer A. Sivak-Callcott, MD Department of Ophthalmology, West Virginia University Eye Institute, Morgantown, West Virginia Supported by Research to Prevent Blindness, Unrestricted Grant, West Virginia University. The authors report no conflicts of interest. REFERENCES 1. Liao YJ, Hwang JJ. Accessory lateral rectus in a patient with normal ocular motor control. J Neuroophthalmol. 2014;34:153-154. 2. Lueder GT. Anomalous orbital structures resulting in unusual strabismus. Surv Ophthalmol. 2002;47:27-35. 3. Savino G, D'Ambrosio A, Tamburrelli C, Colosimo C, Dickmann A. Restrictive limitation of sursumduction caused by an anomalous muscular structure. Ophthalmologica. 1998;212:424-428. 4. DobbsMD, Mawn LA, Donahue SP. Anomalous extraocular muscles with strabismus. AJNR Am J Neuroradiol. 2011;32:E167-E168. 5. Lueder GT, Dunbar JA, Soltau JB, Lee BC, McDermott M. Vertical strabismus resulting from an anomalous extraocular muscle. J AAPOS. 1998;2:126-128. 6. Krasny A, Lutz S, Gramsch C, Diepenbruck S, Schlamann M. Accessory eye muscle in a young boy with external ophthalmoplegia. Clin Anat. 2011;24:948-949. 7. Ozkan SB, Ozsunar Dayanir Y, Gokce Balci Y. Hypoplastic inferior rectus muscle in association with accessory extraocular muscle and globe retraction. J AAPOS. 2007;11:488-490. 8. Valmaggia C, Zaunbauer W, Gottlob I. Elevation deficit caused by accessory extraocular muscle. Am J Ophthalmol. 1996;121:444-445. 9. Merino P, de Liano PG, Ruiz Y, Franco G. Atypical restrictive strabismus secondary to an anomalous orbital structure: differential diagnosis. Strabismus. 2012;20:162-165. Bilateral Intracranial Optic Nerve and Chiasmal Involvement in IgG4-Related Disease We read with great interest the reviews by Yamamoto et al (1) and Kashii (2) on IgG4-related disease (IgG4-RD). We recently evaluated a patient with this disease who experienced bilateral optic nerve involvement. A 36-year-old man presented with acute painful loss of vision and a droopy lid of the right eye. He had developed a right sixth nerve palsy 2 years earlier and brain magnetic resonance imaging (MRI) at that time showed abnormalities of the right cavernous sinus and sphenoid sinus. This prompted a biopsy of a "polyp" from the right sphenoid sinus, which showed an "inflammatory lesion." The patient improved over the next 2 months after treatment with sys-temic corticosteroids. He had a 15-year history of tobacco use, but his medical history was otherwise unremarkable. Visual acuity was hand motions, right eye and 20/20, left eye. There was a right relative afferent pupillary defect with complete ptosis and limitation of right eye movement in all gaze directions. Anterior and posterior segment examinations were normal in both eyes. Automated visual field testing was normal in the left eye. Brain MRI revealed a lesion involving the right cavernous sinus and right prechiasmal optic nerve (Fig. 1A). FIG. 1. A. Postcontrast T1 coronal magnetic resonance imaging shows enhancement of the right prechiasmal optic nerve (arrow), right cavernous sinus, and dura of the middle cranial fossa (arrowhead). B. Two months later, there is enhancement of the left prechiasmal optic nerve (arrow). Letters to the Editor: J Neuro-Ophthalmol 2015; 35: 226-231 229 Letters to the Editor Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.