BACKGROUND More than ever research into changes in the eye caused by long-term space flight is becoming the focus of the international and national space agencies National Aeronautics and Space Administration (NASA), European Space Agency (ESA) and German Aerospace Center (DLR). In addition to space radiation-induced cataract formation considerable eye changes, summarized under space flight-associated neuro-ocular syndrome (SANS), can occur. OBJECTIVE This article gives an overview of the current state of research and future directions in the field of research concerned with ocular alterations in SANS and presents the relevance for terrestrial ophthalmological research. METHODS An analysis of existing publications on SANS in PubMed and reports on the risk of SANS published by the NASA of the USA was carried out. RESULTS The reasons for the development of the eye changes in space have not been clarified. Factors such as the increase in intracranial pressure, fluid shifts, hypercapnia and genetic factors are the subject of intensive research efforts. A terrestrial model for the induction of papilledema could be established (bed rest studies with -6° head-down tilt as a space analogue). Countermeasures for the development of eye changes, such as intermittent artificial gravity, are the subject of current research studies. CONCLUSIONS Research into SANS as part of bed rest studies will provide further important insights in the future for space research and also for terrestrial research. Clinical research projects can be derived from space research.