Prolonged microgravity exposure during long-duration spaceflight (LDSF) produces unusual physiologic and pathologic neuroophthalmic findings in astronauts. These microgravity associated findings collectively define the "Spaceflight Associated Neuroocular 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.npj Microgravity (2020) 6:7 ; https://doi.

An algorithm was created for use in high altitude missions, in the event of an emergency descent and traumatic landing for an unconscious and hypotensive pilot, to rule out most life threatening causes. Each endpoint includes disposition, allowing concise decision-making.Galdamez LA, Clark JB, Antonsen EL. Point-of-care ultrasound utility and potential for high altitude crew recovery missions. Aerosp Med Hum Perform. 2017; 88(2):128-136.

Purpose of review Several decades of long duration space flight missions by the National Aeronautics and Space Administration has revealed an interesting and unique constellation of neuro-ophthalmic findings now called spaceflight associated neuro-ocular syndrome (SANS). The unique space environment of microgravity produces novel physiological changes and derangements that present a challenge to astronauts in current and future long duration space missions. Although the precise mechanism of SANS is not fully understood, in this review, we examine recent developments that may to help explain possible causes and potential countermeasures. Recent findings The cause of SANS is still largely unknown. A growing body of evidence implicates multiple factors that contribute to the development of SANS including cephalad fluid shifts, increased intracranial pressure, venous/lymphatic stasis, inflammation, metabolism, axoplasmic stasis and radiation exposure. Summary The pathologic mechanism behind SANS may be multifactorial and may be amenable to different countermeasures for prevention and management of SANS.

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