The authors explore the clinical entity that is known as Spaceflight Associated Neuro-ocular Syndrome (SANS). Its clinical characteristics include optic disc oedema, hyperopic refractive shifts, globe flattening, and chorioretinal folds, may pose a health risk for future space exploration. Understanding SANS and countermeasures for its prevention is crucial for upcoming crewed space missions and warrants a multidisciplinary approach. This review examines the potential causes and countermeasures of SANS. The authors highlight future research directions for understanding the susceptibilities factors to SANS as well as how to use terrestrial analogues for testing future mitigation strategies.