Investigating the Pathogenesis of Spaceflight Associated Neuroocular Syndrome with Headmounted Visualization Engineering of Pupil Reactivity

Spaceflight associated neuro-ocular syndrome (SANS) refers to a collection of neuro-ophthalmic imaging and clinical findings observed in astronauts during and after long-duration spaceflight (LDSF) [1]. These findings include optic disc edema (ODE), posterior globe flattening, hyperopic refractive error shifts, and chorioretinal folds. Given its risk and consequence on vision and the neuro-ophthalmic system, NASA has deemed that mitigation of SANS is a top priority for a planetary mission to Mars [2]. While a physiological barrier to deep-space exploration, the pathogenesis of SANS is not well understood. Initially termed "Vision Impairment and Intracranial Pressure", it was initially thought that cephalad fluid shifts during spaceflight led to increased intracranial pressure (ICP) and subsequent SANS findings such as ODE. However, there are several discrepancies between terrestrial elevations of ICP and SANS including lumbar puncture opening pressure values in SANS astronauts post-flight which have been normal or only mildly elevated. However, given its invasive nature, lumbar punctures are not available during spaceflight [1].