Spaceflight associated neuro-ocular syndrome (SANS) and the neuro-ophthalmologic effects of microgravity: a review and an update

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Abstract

Prolonged microgravity exposure during long-duration spaceflight (LDSF) produces unusual physiologic and pathologic neuro-ophthalmic findings in astronauts. These microgravity associated findings collectively define the “Spaceflight Associated Neuro-ocular Syndrome” (SANS). We compare and contrast prior published work on SANS by the National Aeronautics and Space Administration’s (NASA) Space Medicine Operations Division with retrospective and prospective studies from other research groups. In this manuscript, we update and review the clinical manifestations of SANS including: unilateral and bilateral optic disc edema, globe flattening, choroidal and retinal folds, hyperopic refractive error shifts, and focal areas of ischemic retina (i.e., cotton wool spots). We also discuss the knowledge gaps for in-flight and terrestrial human research including potential countermeasures for future study. We recommend that NASA and its research partners continue to study SANS in preparation for future longer duration manned space missions.

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Most cited references 75

Record: found
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Article: not found

Effects of Spaceflight on Astronaut Brain Structure as Indicated on MRI

Donna R. Roberts, Moritz Albrecht, Heather Collins … (2017)

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Record: found
Abstract: found
Article: not found

Ischemic optic neuropathy.

Sohan Hayreh (2009)

Ischemic optic neuropathy is one of the major causes of blindness or seriously impaired vision, yet there is disagreement as to its pathogenesis, clinical features and especially its management. This is because ischemic optic neuropathy is not one disease but a spectrum of several different types, each with its own etiology, pathogenesis, clinical features and management. They cannot be lumped together. Ischemic optic neuropathy is primarily of two types: anterior (AION) and posterior (PION), involving the optic nerve head (ONH) and the rest of the optic nerve respectively. Furthermore, both AION and PION have different subtypes. AION comprises arteritic (A-AION - due to giant cell arteritis) and, non-arteritic (NA-AION - due to causes other than giant cell arteritis); NA-AION can be further classified into classical NA-AION and incipient NA-AION. PION consists of arteritic (A-PION - due to giant cell arteritis), non-arteritic (NA-PION - due to causes other than giant cell arteritis), and surgical (a complication of several systemic surgical procedures). Thus, ischemic optic neuropathy consists of six distinct types of clinical entities. NA-AION is by far the most common type and one of the most prevalent and visually crippling diseases in the middle-aged and elderly. A-AION, though less common, is an ocular emergency and requires early diagnosis and immediate treatment with systemic high dose corticosteroids to prevent further visual loss, which is entirely preventable. Controversy exists regarding the pathogenesis, clinical features and especially management of the various types of ischemic optic neuropathy because there are multiple misconceptions about its many fundamental aspects. Recently emerging information on the various factors that influence the optic nerve circulation, and also the various systemic and local risk factors which play important roles in the development of various types of ischemic optic neuropathy have given us a better understanding of their pathogeneses, clinical features and management. This knowledge should help us not only to manage them better but also to reduce their incidence. For example, clinically, the evidence that about 40% of NA-AION eyes experience spontaneous improvement in visual acuity and that systemic steroid therapy during early stages in both NA-AION and NA-PION has a significant beneficial effect for visual outcome are encouraging developments. This review discusses the current concepts on various issues related to various types of ischemic optic neuropathy.

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Effect of gravity and microgravity on intracranial pressure.

Justin S Lawley, Lonnie G. Petersen, Erin J Howden … (2017)

Astronauts have recently been discovered to have impaired vision, with a presentation that resembles syndromes of elevated intracranial pressure on Earth. Gravity has a profound effect on fluid distribution and pressure within the human circulation. In contrast to prevailing theory, we observed that microgravity reduces central venous and intracranial pressure. This being said, intracranial pressure is not reduced to the levels observed in the 90 deg seated upright posture on Earth. Thus, over 24 h in zero gravity, pressure in the brain is slightly above that observed on Earth, which may explain remodelling of the eye in astronauts.

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Author and article information

Contributors

Andrew G. Lee: aglee@houstonmethodist.org

Journal

Journal ID (nlm-ta): NPJ Microgravity

Journal ID (iso-abbrev): NPJ Microgravity

Title: NPJ Microgravity

Publisher: Nature Publishing Group UK (London )

ISSN (Electronic): 2373-8065

Publication date (Electronic): 7 February 2020

Publication date PMC-release: 7 February 2020

Publication date Collection: 2020

Volume: 6

Electronic Location Identifier: 7

Affiliations

[1 ]ISNI 0000 0004 0445 0041, GRID grid.63368.38, Department of Ophthalmology, , Houston Methodist Hospital, ; Houston, TX USA

[2 ]ISNI 0000 0001 2160 926X, GRID grid.39382.33, Baylor College of Medicine and The Baylor Center for Space Medicine, ; Houston, TX USA

[3 ]ISNI 000000041936877X, GRID grid.5386.8, Departments of Ophthalmology, Neurology, and Neurosurgery, , Weill Cornell Medical College, ; New York, NY USA

[4 ]ISNI 0000 0001 1547 9964, GRID grid.176731.5, Department of Ophthalmology, , The University of Texas Medical Branch, ; Galveston, TX USA

[5 ]ISNI 0000 0004 0434 9816, GRID grid.412584.e, Department of Ophthalmology, , The University of Iowa Hospitals and Clinics, ; Iowa City, IA USA

[6 ]ISNI 0000 0001 2291 4776, GRID grid.240145.6, UT MD Anderson Cancer Center, ; Houston, TX USA

[7 ]Colonel (R) US Army, Moab, UT USA

[8 ]Coastal Eye Associates, Webster, TX USA

[9 ]ISNI 0000 0004 0613 2864, GRID grid.419085.1, Space Flight Associated Neuro-ocular Syndrome (SANS) Clinical Lead, Clinical Services, , NASA Johnson Space Center, ; Houston, TX USA

[10 ]ISNI 0000 0000 9206 2401, GRID grid.267308.8, Department of Diagnostic and Interventional Imaging, , University of Texas Health Science Center at Houston, ; Houston, TX USA

[11 ]ISNI 0000 0004 0613 2864, GRID grid.419085.1, U.S. Navy Detailed to NASA Johnson Space Center, ; Houston, TX USA

[12 ]ISNI 0000 0001 2160 926X, GRID grid.39382.33, Department of Emergency Medicine, , Baylor College of Medicine, ; Houston, TX USA

Article

Publisher ID: 97

DOI: 10.1038/s41526-020-0097-9

PMC ID: 7005826

PubMed ID: 32047839

SO-VID: aace472e-7a3f-4cc8-bd2f-8c0562e34aac

License:

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.