Binasal Visual Field Defects Due to Sickle Cell Maculopathy

A 26-year-old African American man with sickle cell disease noticed blurry vision in both eyes after a recent complicated hospital admission for sickle cell crisis. Anterior and posterior segment examination of each eye was normal, but visual field testing revealed binasal scotomas. Optical coherence tomography of the macula demonstrated severe thinning of the temporal inner retina, suggesting previous bilateral occlusions of terminal retinal arterioles involving the temporal macula, an uncommon complication of sickle cell disease. This case is a reminder that retinal pathology should always be considered as a potential cause of unexplained visual field defects and highlights the role of macular OCT in evaluation of these patients,

Photo and Video Essay Section Editors: Melissa W. Ko, MD Dean M. Cestari, MD Peter Quiros, MD Binasal Visual Field Defects Due to Sickle Cell Maculopathy Jason M. Kwok, MD, Trishal Jeeva-Patel, MD, Edward A. Margolin, MD FIG. 1. Visual fields (Automated 24-2 algorithm) demonstrating binasal paracentral scotomas in the left and right eyes. Abstract: A 26-year-old African American man with sickle cell disease noticed blurry vision in both eyes after a recent complicated hospital admission for sickle cell crisis. Anterior and posterior segment examination of each eye was normal, but visual field testing revealed binasal scotomas. Optical coherence tomography of the macula demonstrated severe thinning of the temporal inner retina, suggesting previous bilateral occlusions of terminal retinal arterioles involving the temporal macula, an uncommon complication of sickle cell disease. This case is a reminder that retinal pathology should always be considered as a potential cause of unexDepartment of Ophthalmology and Vision Sciences (JMK, TJ-P, EAM), University of Toronto, Toronto, Canada; and Division of Neurology (EAM), Department of Medicine, University of Toronto, Toronto, Canada. The authors report no conflicts of interest. Address correspondence to Edward A. Margolin, MD, Ophthalmology and Vision Sciences, University of Toronto Faculty of Medicine, 801 Eglinton Avenue West, Suite 301, Toronto, ON M5N 1E3, Canada; E-mail: [e-mail] e434 plained visual field defects and highlights the role of macular OCT in evaluation of these patients. Journal of Neuro-Ophthalmology 2022;42:e434–e436 doi: 10.1097/WNO.0000000000001299 © 2021 by North American Neuro-Ophthalmology Society A 26-year-old African American man with a history of hemoglobin SS sickle cell disease noticed blurry vision in both eyes. He was recently admitted to the intensive care unit (ICU) for acute chest syndrome secondary to multiple pulmonary emboli due to sickle cell crisis. He required ventilatory support for 11 days and treatment with vasopressors for systemic hypotension; he also received an exchange transfusion to treat the underlying sickle cell disease. After extubation, he noticed persistent blurry vision in both eyes. MRI of the brain with contrast was performed but was unrevealing. He denied any ocular history and had a normal ophthalmologic examination before this hospital Kwok et al: J Neuro-Ophthalmol 2022; 42: e434-e436 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Photo and Video Essay admission. His medications included rivaroxaban, folic acid, melatonin, and multivitamins. On examination 2 months after the ICU discharge, visual acuity was 20/40 in both eyes. Intraocular pressures were normal, and there was no relative afferent pupillary defect. Slit-lamp examination and dilated fundus examination were normal, with no signs of sickle cell retinopathy. Both optic nerves appeared pink with a cup-to-disc ratio of 0.3 in each eye. Fundus autofluorescence testing was normal. Formal visual fields (Automated 24-2 algorithm) demonstrated nasal paracentral scotomas in each eye (Fig. 1). Optical coherence tomography (OCT) of the retinal nerve fiber layers was normal. An OCT of the macula was performed showing preferential thinning of the inner retina temporal to the fovea in both eyes suggesting previous retinal arterial occlusions involving the temporal macula (Fig. 2A, B). A diagnosis of bilateral temporal macular ischemia secondary to sickle cell disease was made. This patient has binasal paracentral visual field defects after a complicated hospital admission due to sickle cell disease. Although he had a normal ophthalmological examination at bedside, confrontational visual fields might have been useful in revealing binasal nature of his defects, which never occur secondary to chiasmal and/or retrochiasmal pathology. As both optic nerves seemed normal several months after the onset of blurry vision on ophthalmoscopy and peripapillary OCT was normal in each eye as well, bilateral anterior visual pathway lesions were equally unlikely to be the cause of this visual field defects. Thus, other causes of visual field defects were considered with retinal pathology being a potential culprit because it can produce bilateral visual field defects that do not respect either vertical or horizontal midline when optic nerves seem normal and neuro-imaging of the retrochiasmal pathway is unre- markable. In this case, an OCT of the macula was instrumental in making a correct diagnosis by demonstrating severe thinning of the temporal inner retina in each eye that corresponded to nasal visual field defects. Retinal arterial occlusions typically occur secondary to an embolic source and result in the edema of the affected retinal territory in the acute period, clinically appearing as retinal whitening. After the resolution of retinal edema, the retina often seems normal. Thus, resolved retinal arterial occlusive events are difficult to diagnose on ophthalmoscopy. Severe thinning of the inner retina, however, is a permanent sequela of retinal arterial occlusion. The inner retina is supplied by the branches of central retinal artery, thus the hallmark of any retinal arterial occlusion is thinning of the inner retina in the territory corresponding to the involved artery, with preservation of the outer retinal structures that derive their blood supply by diffusion from the rich choroidal circulation that is supplied by the branches of short posterior ciliary arteries. These findings can be detected on macular OCT, as illustrated in Figure 2A, B. The etiology of bilateral retinal artery occlusions in this case of sickle cell maculopathy, instead of an embolus in the retinal arterial circulation that is the most common cause of retinal arterial occlusions, is most likely decreased perfusion of the arterioles supplying temporal macula, which is a watershed zone in the retina. This was in turn secondary to severe hypotension this patient suffered while in the ICU that was exacerbated by the sludging of the blood flow in the most distal arterioles due to sickle cell disease (1). Macular ischemia is a known complication of sickle cell disease characterized by localized thinning of the temporal macula secondary to sickling red blood cells in the perifoveal vessels (1–3). If ischemia is severe, it can result in scotomas, impaired color vision, and loss of contrast sensitivity (4). The predilection of the temporal macula to retinal infarction can result in corresponding nasal visual field defects (5). FIG. 2. OCT macula of the left (A) and right (B) eyes demonstrating bilateral thinning of the temporal macula (arrows). OCT, optical coherence tomography. Kwok et al: J Neuro-Ophthalmol 2022; 42: e434-e436 e435 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Photo and Video Essay The binasal scotomas seen in our patient matched the areas of retinal thinning in the temporal macula thus explaining his blurry vision. This case highlights the entity of ischemic temporal maculopathy in patients with sickle cell disease and is a reminder that formal visual fields should be performed in all patients complaining of blurry vision without other obvious pathology that can account for their symptoms and that retinal pathology should always be considered as a potential etiology of visual field defects. It also highlights the utility of macular OCT in neuroophthalmology practice that can help detect subtle macular disease that cannot be appreciated on fundus examination. STATEMENT OF AUTHORSHIP Category 1: a. Conception and design: E. A. Margolin, T. Jeeva-Patel, and J. M. Kwok; b. Acquisition of data: E. A. Margolin, T. Jeeva-Patel, and J. M. Kwok; c. Analysis and interpretation of data: E. A. Margolin, T. Jeeva-Patel, and J. M. Kwok. Category 2: a. Drafting the e436 manuscript: E. A. Margolin, T. Jeeva-Patel, and J. M. Kwok; b. Revising it for intellectual content: E. A. Margolin, T. Jeeva-Patel, and J. M. Kwok. Category 3: a. Final approval of the completed manuscript: E. A. Margolin, T. Jeeva-Patel, and J. M. Kwok. REFERENCES 1. Acacio I, Goldberg MF. Peripapillary and macular vessel occlusions in sickle cell anemia. Am J Ophthalmol. 1973;75:861–866. 2. Witkin AJ, Rogers AH, Ko TH, Fujimoto JG, Schuman JS, Duker JS. Optical coherence tomography demonstration of macular infarction in sickle cell retinopathy. Arch Ophthalmol. 2006;124:746–747. 3. Chalam KV, Shah VA. Macular infarction a presentation of sickle cell crisis. Eye. 2004;18:1277–1278. 4. Martin GC, Dénier C, Zambrowski O, Grévent D, Bruère L, Brousse V, de Montalembert M, Brémond-Gignac D, Robert MP. Visual function in asymptomatic patients with homozygous sickle cell disease and temporal macular atrophy. JAMA Ophthalmol. 2017;135:1100–1105. 5. Cusick M, Toma HS, Hwang TS, Brown JC, Miller NR, Adams NA. Binasal visual field defects from simultaneous bilateral retinal infarctions in sickle cell disease. Am J Ophthalmol. 2007;143:893–896. Kwok et al: J Neuro-Ophthalmol 2022; 42: e434-e436 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.