Abstract
Ophthalmic abnormalities including unilateral and bilateral optic disc edema, optic nerve sheath distention, globe flattening, choroidal folds, and hyperopic shifts have been observed in astronauts during and after long-duration spaceflight. An increased understanding of factors contributing to this syndrome, termed spaceflight-associated neuro-ocular syndrome, is currently a top priority for the ESA and NASA, especially since this medical obstacle could impact the visual health of astronauts as well as the success of future missions, including continued trips to the International Space Station, a return to the moon, or a future human mission to Mars. Currently, the exact mechanisms causing this neuro-ocular syndrome are not fully understood. In the present paper, we propose a hypothetical framework by which optic disc edema in astronauts may result, at least partly, from the forcing of perioptic cerebrospinal fluid into the optic nerve and optic disc along perivascular spaces surrounding the central retinal vessels, related to long-standing microgravity fluid shifts and variations in optic nerve sheath anatomy and compliance. Although this hypothesis remains speculative at the present time, future research in this area of investigation could not only provide exciting new insights into the mechanisms underlying microgravity-induced optic disc swelling but also offer opportunities to develop countermeasure strategies.
摘要
宇航员在历经长期太空飞行和重返地球后的眼部异常改变, 包括单侧或双侧视盘水肿、视神经鞘扩张、眼球扁平化、脉络膜皱褶、远视偏移。对于这种被称为航天相关的神经-眼综合征的发病机制研究, 是目前欧洲航天局和美国国家航空航天局的首要任务, 尤其是此医学难题会影响宇航员的视觉健康以及未来航天任务的顺利完成, 包括继续前往国际空间站、重返月球和人类未来的火星计划。目前, 引起这种神经-眼综合症的发病机制还未完全明确。本文提出了一种关于宇航员视盘水肿发病机制的假说, 其中可能的因素是眼球后的脑脊液沿着视网膜中央血管的周围间隙流入了视神经和视盘, 这与长期微重力环境下的流体移动和视神经鞘的解剖结构及顺应性的变化有关。虽然这项假说目前尚未被证实, 但今后关于此方面的研究不仅可为微重力环境下视盘水肿的发病机制提供令人振奋新的观点, 而且为制定及应对的决策提供机会。
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PW is the inventor of a pending patent application pertaining biomarkers for spaceflight-associated neuro-ocular syndrome. The other authors declare that they have no conflict of interest.
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Wostyn, P., Mader, T.H., Gibson, C. et al. The escape of retrobulbar cerebrospinal fluid in the astronaut’s eye: mission impossible?. Eye 33, 1519–1524 (2019). https://doi.org/10.1038/s41433-019-0453-8
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DOI: https://doi.org/10.1038/s41433-019-0453-8
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