Bilateral Optic Disc Edema in Multisystem Inflammatory Syndrome in Children (MIS-C) Associated With COVID-19: The Value and Limitations of Optical Coherence Tomography: Response

Letters to the Editor Bilateral Optic Disc Edema in Multisystem Inflammatory Syndrome in Children (MIS-C) Associated With COVID-19: The Value and Limitations of Optical Coherence Tomography: Response W e are grateful to Deekshitha Umasankar, BSc, and Lauren Elizabeth Church, MSc, for their insightful letter commenting on the use of optical coherence tomography (OCT) in the assessment of patients with spaceflightassociated neuro-ocular syndrome and patients with elevated intracranial pressure. As they point out, OCT offers us the ability to follow optic nerve morphology noninvasively, which can be of particular importance in the pediatric population, in which minimizing procedure-associated distress is of great importance. Peripapillary retinal nerve fiber layer (pRNFL) thickness, optic nerve volume, and the angle of deformation of Bruch membrane (1) all may change with modulations in intracranial pressure and can help differentiate low-grade papilledema from congenital pseudopapilledema or from other forms of disc edema that occur in the absence of elevated intracranial pressure (ICP). In patients with idiopathic intracranial hypertension (IIH), optic nerve head volume parameters, such as central thickness, seem to correlate well with changes in ICP, whereas the mean pRNFL does not (2). Furthermore, new observations, such as the perivascular hyporeflective regions postulated to represent dilated glymphatic channels (3), offer even greater insights into the pathophysiology of papilledema. With our ability to detect elevated ICP with funduscopy, and now to follow it quantitatively with OCT, some have argued that lumbar puncture is not necessary to diagnose IIH (4) when the clinical picture is strongly suggestive of the diagnosis. Nevertheless, we would like to emphasize that the parameters on OCT cannot be used to determine an exact ICP nor the underlying etiology. As such, even in the Comments on “Embolic Abducens Palsy and Central Retinal Artery Occlusion (CRAO) in a Patient With COVID-19” W e read with interest the clinical correspondence entitled “Embolic Abducens Palsy and Central Retinal Artery Occlusion (CRAO) in a Patient with COVID-19” (1), it was a case report by Larochelle et al on multiple systemic embolic injuries in a 68-year-old Caucasian man diagnosed with COVID-19. It was highlighted that this patient had central retinal artery occlusion (CRAO) in the right eye secondary to occlusive thrombus in the internal carotid artery (ICA). CRAO is a blinding ocular emergency and a harbinger of ischemic cerebrovascular stroke. It is the ocular equivalent of an ischemic stroke. As ophthalmologists in the hyperbaric oxygen therapy for central retinal e358 pediatric population, neuroimaging and lumbar puncture (LP) are still usually required for accurate diagnosis. In our case, we chose to defer LP because the child's headache and disc edema were spontaneously and rapidly improving, but in the absence of that improvement, we would have felt compelled to sample the cerebrospinal fluid to differentiate an infectious meningitis from secondary inflammation or idiopathic intracranial hypertension. We hope that the shared utility of technologies, such as OCT, in the fields of Neuro-Ophthalmology and Space Medicine will lead to further collaboration between our 2 disciplines in the future. Marc Dinkin, MD, Cristiano Oliveira, MD Department of Ophthalmology, Weill Cornell Medicine, New York Hospital, New York, New York, Department of Neurology, Weill Cornell Medicine, New York, New York; and Department of Neurology, Weill Cornell Medicine, New York, New York The authors report no conflicts of interest. REFERENCES 1. Kupersmith MJ, Sibony P, Mandel G, Durbin M, Kardon RH. Optical coherence tomography of the swollen optic nerve head: deformation of the peripapillary retinal pigment epithelium layer in papilledema. Invest Ophthalmol Vis Sci. 2011;52:6558– 6564. 2. Vijay V, Mollan SP, Mitchell JL, Bilton E, Alimajstorovic Z, Markey KA, Fong A, Walker JK, Lyons HS, Yiangou A, Tsermoulas G, Brock K, Sinclair AJ. Using optical coherence tomography as a surrogate of measurements of intracranial pressure in idiopathic intracranial hypertension. JAMA Ophthalmol. 2020;138:1264– 1271. 3. Wostyn P, De Winne F, Stern C, Mader TH, Gibson CR, De Deyn PP. Potential involvement of the ocular glymphatic system in optic disc edema in astronauts. Aerosp Med Hum Perform. 2020;91:975–977. 4. Moss HE, Margolin EA, Lee AG, Van Stavern GP. Should lumbar puncture be required to diagnose every patient with idiopathic intracranial hypertension? J Neuroophthalmol. 2021;41:379– 384. artery occlusion (HORA) study, we are gathering global data on the incidence and correlation of CRAO with COVID-19. Our tertiary CRAO referral center has treated 15 acute CRAO cases with hyperbaric oxygen therapy (HBOT) under COVID-19 local outbreak, but there were no cases tested positive for SARS-CoV-2 before or after the CRAO episode; the mean follow-up period was 5 months. Ocular manifestation of COVID-19 has long been a hot debate and research topic, and there were only 3 case reports for COVID-19–related CRAO (2–4) and 1 case of COVID-19–related ophthalmic artery occlusion (OAO) (5) after comprehensive search over PubMed, MEDLINE, EMBASE, Cochrane library, and Google Scholar with the terms [“central retinal artery occlusion” OR “CRAO”] AND [“COVID” OR “coronavirus”] as of January 16, 2021. The CRAO case presented by Larochelle et al in the Letters to the Editor: J Neuro-Ophthalmol 2023; 43: e356-362 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.