Binocular Diplopia Caused by an Epiretinal Membrane With Foveal Displacement

A 73-year-old woman presented with 3 years of monocular visual distortion and progressive binocular diplopia. She was found to have a comitant left hypertropia due to an epiretinal membrane causing inferior foveal drag. Displacement of the fovea from an epiretinal membrane is a likely under-recognized cause ocular cause of a comitant binocular diplopia.

Photo Essay Section Editors: Melissa W. Ko, MD Dean M. Cestari, MD Binocular Diplopia Caused by an Epiretinal Membrane With Foveal Displacement Doria M. Gold, MD, Yasha S. Modi, MD, Floyd A. Warren, MD, Janet C. Rucker, MD FIG. 1. Fundus photographs of the right and left eyes. Ophthalmoscopic views of (A) the normal right eye and (B) downward macular displacement in the left eye. An enlarged view (C) shows an epiretinal membrane with trace inner retinal striae. Infrared imaging of the right eye (D) and left eye (E) shows the foveal positions relative to the optic discs indicated by horizontal tangent (black) lines and relative fovea centralis positions (black arrows). Abstract: A 73-year-old woman presented with 3 years of monocular visual distortion and progressive binocular diplopia. She was found to have a comitant left hypertropia due to an epiretinal membrane causing inferior foveal drag. Displacement of the fovea from an epiretinal membrane is a likely underrecognized cause ocular cause of a comitant binocular diplopia. Journal of Neuro-Ophthalmology 2020;40:110-111 doi: 10.1097/WNO.0000000000000824 © 2019 by North American Neuro-Ophthalmology Society A 73-year-old woman with a medical history of hypertension, hypothyroidism, diabetes mellitus, and breast cancer now in remission after radiation therapy several years Departments of Neurology (DMG), Ophthalmology (YSM), and Neurology and Ophthalmology (FAW, JCR), NYU Langone Health, New York, New York. The authors report no conflicts of interest. Y. S. Modi is a consultant to Allergan, Alimera Sciences and Genentech. The remaining authors report no conflicts of interest. Address correspondence to Doria M. Gold, MD, Departments of Neurology and Ophthalmology, NYU Langone Health, 222 E. 41st Street, 14th Floor New York, NY 10017; E-mail: [e-mail] 110 ago developed monocular visual distortion and progressive binocular diplopia. The patient reported 3 years of visual blurring, macropsia, and metamorphopsia in her left eye. There was additional gradual development of vertical binocular diplopia. Symptoms were present both at distance and at near. Her oncologist ordered an MRI of the brain with and without intravenous contrast; this was notable only for microvascular disease. Examination revealed bestcorrected visual acuities of 20/20-1 in both eyes; there were distorted images when viewing with the left eye. Color vision and visual fields were normal. Pupils were equally reactive without an afferent defect. Ocular ductions were full without nystagmus. She noted distortion of lines on Amsler grid testing with the left eye. The patient had a comitant 2prism diopter left hypertropia in all gaze directions and head tilt positions. On funduscopic examination, optic discs were normal; however, there was an epiretinal membrane in her left eye causing foveal ectopia due to inferior dragging of the fovea (Fig. 1 A-E). She was fitted with a 1-diopter base-down prism in the left spectacle lens with resolution of diplopia. Downward displacement of the left fovea relative to the optic disc causes adjustment of foveal fixation. This results in a left hypertropia. As seen on the OCT infrared photograph, Gold et al: J Neuro-Ophthalmol 2020; 40: 110-111 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Photo Essay the fovea centralis is typically superior to a tangent line drawn to the inferior border of the optic disc (Fig. 1D). In our patient, the fovea centralis of the left eye is dragged downward relative to the inferior border of the optic disc by the epiretinal membrane (Fig. 1E). Although we cannot fully exclude the common entity of the sagging eye syndrome as a possible cause of our patient's diplopia, the dragged fovea centralis and the fact that our patient lacked the supraduction defect and excyclotorsion in the hypotropic eye (both characteristic of the sagging eye syndrome) make the epiretinal membrane a more likely etiology (1). Diplopia attributed to epiretinal membranes has been attributed to foveal drag, resulting in competing central and peripheral fusion. Contrary to our experience with this patient, this phenomenon has been reported to be poorly responsive to prism therapy that targets central fusion. There have, however, been cases described of diplopia attributed to epiretinal membranes that did respond to prism therapy. This was the case in 2 separate series by Burgess et al and Bixenman and Joffe, as well as Barton (225). Furthermore, when looking at patients with confirmed an epiretinal membrane, Veverka et al (6) identified 15/25 patients who did not have symptomatic diplopia but did have evidence of retinal misregistration. DePool suggested that if there is sufficient central scotoma causing central suppression, prism therapy might result in alignment peripherally (2). Alternatively, as Bixenman and Joffe consider, a lesser degree of retinal distortion could re-establish a normal association between central and peripheral fusion (5). One might speculate that, just as different patients have different fusional amplitudes, it is possible that the capacity of an individual to fuse peripherally, the degree of distortion caused by the epiretinal membrane, the specific location of the epiretinal membrane, and the direction of foveal drag may influence a patient's ability to fuse peripherally in the presence of a prism. This patient's symptoms of metamorphopsia and blurring are classic for an epiretinal membrane; in this case, the Gold et al: J Neuro-Ophthalmol 2020; 40: 110-111 membrane caused significant foveal drag (2-4,6). Both the degree of drag and the distorted images seen by the left eye exceeded the patient's fusional capacity. Perhaps, the location of the epiretinal membrane and the mild metamorphopsia allowed for symptomatic correction. Displacement of the fovea from an epiretinal membrane is one ocular cause of a comitant binocular diplopia that is likely under-recognized (2-6). STATEMENT OF AUTHORSHIP Category 1: a. Conception and design: Yasha S. Modi, Janet C. Rucker, and Doria M. Gold; b. Acquisition of data: Doria M. Gold, Janet C. Rucker, and Yasha S. Modi; c. Analysis and interpretation of data: Doria M. Gold, Yasha S. Modi, Floyd A. Warren, and Janet C. Rucker. Category 2: a. Drafting the manuscript: Doria M. Gold; b. Revising it for intellectual content: Doria M. Gold, Yasha S. Modi, Floyd A. Warren, and Janet C. Rucker. Category 3: a. Final approval of the completed manuscript: Doria M. Gold, Yasha S. Modi, Floyd A. Warren, and Janet C. Rucker. REFERENCES 1. Chaudhuri Z, Demer JL. Sagging eye syndrome: connective tissue involution as a cause of horizontal and vertical strabismus in older patients. JAMA Ophthalmol. 2013;131:619-625. 2. De Pool ME, Campbell JP, Broome SO, Guyton DL. The draggedfovea diplopia syndrome: clinical characteristics, diagnosis, and treatment. Ophthalmology. 2005;112:1455-1462. 3. Barton JJS. "Retinal diplopia" associated with macular wrinkling. Neurology 2004;63:925-927. 4. Burgess D, Roper-Hall G, Burde RM. Binocular diplopia associated with subretinal neovascular membranes. Arch Ophthalmol. 1980;98:311-317. 5. Bixenman WW, Joffe L. Binocular diplopia associated with retinal wrinkling. J Pediatr Ophthalmol Strabismus. 1984;21:215-219. 6. Veverka KK, Hatt SR, Leske DA, Brown WL, Iezzi R Jr, Holmes JM. Causes of diplopia in patients with epiretinal membranes. Am J Ophthalmol. 2017;179:39-45. 111 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.