The ocular surface during spaceflight: Post-mission symptom report, extraterrestrial risks, and in-flight therapeutics.

Ocular health is critical for overall astronaut health requirements given its essential role for mission performance and safety. The ocular surface is a vital structure to the visual system and is essential for ocular protection and the refraction of light for focused vision. Data from the 2024 NASA Lifetime Surveillance of Astronaut Health identified that Space Shuttle and International Space Station (ISS) astronauts (N = 257) queried during post-flight eye exams reported symptoms of eye irritation (34 %), dry eyes (14 %), and foreign body sensation (21 %).

Does Long-Duration Exposure to Microgravity Lead to Dysregulation of the Brain and Ocular Glymphatic Systems?

Spaceflight-associated neuro-ocular syndrome (SANS) has been well documented in astronauts both during and after long-duration spaceflight and is characterized by the development of optic disc edema, globe flattening, choroidal folds, and hyperopic refractive error shifts. The exact mechanisms underlying these ophthalmic abnormalities remain unclear. New findings regarding spaceflight-associated alterations in cerebrospinal fluid spaces, specifically perivascular spaces, may shed more light on the pathophysiology of SANS.

The odyssey of the ocular and cerebrospinal fluids during a mission to Mars: the "ocular glymphatic system" under pressure.

A significant proportion of the astronauts who spend extended periods in microgravity develop ophthalmic abnormalities including optic disc edema, globe flattening, chorioretinal folds, and hyperopic refractive error shifts. A constellation of these neuro-ophthalmic findings has been termed "spaceflight-associated neuro-ocular syndrome". Understanding this syndrome is currently a top priority for NASA, especially in view of future long-duration missions (e.

Potential Involvement of the Ocular Glymphatic System in Optic Disc Edema in Astronauts.

A significant proportion of the astronauts who spend extended periods in microgravity develop ophthalmic abnormalities, including optic disc edema, optic nerve sheath distention, globe flattening, chorioretinal folds, hyperopic refractive error shifts, and nerve fiber layer infarcts. A constellation of these neuro-ophthalmic findings has been termed spaceflight-associated neuro-ocular syndrome. An increased understanding of factors contributing to this syndrome is one of the top priorities for ESA and NASA because the length of missions is expected to increase substantially in the future.

The escape of retrobulbar cerebrospinal fluid in the astronaut's eye: mission impossible?

Ophthalmic abnormalities including unilateral and bilateral optic disc edema, optic nerve sheath distention, globe flattening, choroidal folds, and hyperopic shifts have been observed in astronauts during and after long-duration spaceflight. An increased understanding of factors contributing to this syndrome, termed spaceflight-associated neuro-ocular syndrome, is currently a top priority for the ESA and NASA, especially since this medical obstacle could impact the visual health of astronauts as well as the success of future missions, including continued trips to the International Space Station, a return to the moon, or a future human mission to Mars. Currently, the exact mechanisms causing this neuro-ocular syndrome are not fully understood.

Neuro-Ophthalmology of Space Flight.

Background: To describe the history, clinical findings, and possible pathogenic etiologies of the constellation of neuro-ophthalmic findings discovered in astronauts after long-duration space flight and to discuss the terrestrial implications of such findings.

Evidence Acquisition: Retrospective review of published observational, longitudinal examination of neuro-ophthalmic findings in astronauts after long-duration space flight; analysis of postflight questionnaires regarding in-flight vision changes in approximately 300 additional astronauts; and hypothesis generating for developing possible future countermeasures and potential implications for neuro-ophthalmic disorders on Earth. Astronauts with neuro-ophthalmic findings, which were not present at the start of a space flight mission and only seen on return from long-duration space missions to the International Space Station, will be discussed.