The optic nerve in spaceflight: novel concepts in the pathogenesis of optic disc edema in microgravity

Spaceflight-associated neuro-ocular syndrome (SANS) encompasses a unique constellation of neuro-ocular findings in astronauts, including optic disc edema (ODE), globe flattening, chorioretinal folds, and hyperopic refractive shift. Although there are numerous neuro-ocular findings in SANS, the purpose of this review is to describe the novel, emerging concepts of the pathogenesis for the ODE specifically in SANS.