To establish a framework for diagnosing and managing spaceflight-associated neuro-ocular syndrome (SANS) affecting astronauts during long-duration spaceflights.
Approach:
Expert Consensus: A consensus was developed by NASA SANS specialists and experts in cerebrospinal fluid disorders to harmonize case identification and guide clinical decision-making.
Key Findings:
81% of NASA astronauts assessed after long-duration spaceflight exhibited at least one feature of SANS.
Early changes in SANS are common in microgravity, with severity increasing with mission duration and repeated exposure.
Structural changes such as globe flattening and axial length alteration can persist for years after returning to Earth.
Optical coherence tomography (OCT) is central to the proposed diagnostic approach, with specific increases in retinal thickness indicating optic disc edema.
Interpretation:
SANS presents significant clinical risks for astronauts, including hyperopic shift and visual field changes, and requires standardized diagnosis and monitoring.
Limitations:
Astronaut cohorts are small, and evidence regarding SANS is limited.
The pathophysiology of SANS remains unresolved, with no terrestrial disease serving as a perfect model.
Conclusion:
SANS represents an emerging neuro-ophthalmic condition that necessitates careful monitoring and credible countermeasures as spaceflight duration increases.
