Spaceflight-Associated Neuro-ocular Syndrome (SANS): a review of proposed mechanisms and analogs

Abstract

ABSTRACT Introduction Over the last decade, many neuro-ocular findings have been documented following long-duration spaceflight (LDSF) including optic disc edema, choroidal folds, hyperopic refractive shift, and cotton wool spots. These are currently classified under the term Spaceflight-Associated Neuro-Ocular Syndrome (SANS). SANS is unique to space flight with no direct terrestrial analog. The exact pathogenesis is a subject of much debate and poses questions about the long-term impact of SANS on future human spaceflight missions. Areas Covered In this review, we explore the current understanding of SANS including the different proposed etiologies and comparable terrestrial analogs. A systematic but selective review of literature published about SANS and related ocular diseases was conducted. Databases searched include PubMed and Scopus. This information was used to generate a review on potential mechanisms and analogs related to SANS. Expert Opinion This review discusses the current status and future directions for SANS research, the role private space companies play in increasing access to space flight, and the possibility of future high-quality human spaceflight research in microgravity. We hope that the work on SANS can inspire technological innovation, increase our knowledge of terrestrial disorders, and possibly creating downstream spin-off technologies that have wider applications beyond space flight alone.