Standardizing SANS in Spaceflight

NASA experts set out new diagnostic and management guidance for spaceflight-associated neuro-ocular syndrome

August 27, 2026
4 min

The Ophthalmologist

Overview

A new expert consensus outlines a framework for diagnosing and managing spaceflight-associated neuro-ocular syndrome (SANS), which affects astronauts during long-duration missions. Key findings include the identification of early indicators of optic disc edema and the need for standardized monitoring.

Background

As human spaceflight extends beyond low Earth orbit, understanding and managing SANS is critical. This condition, first identified in 2011, poses risks to astronauts' ocular health during prolonged exposure to microgravity. The consensus aims to harmonize diagnostic criteria and management strategies.

Data Highlights

No numerical data available in the source material.

Key Findings

81% of NASA astronauts assessed after long-duration spaceflight exhibit at least one feature of SANS.
Optic disc edema is indicated by an average increase of 20 µm in peripapillary total retinal thickness.
A 55 µm increase in retinal thickness or Frisén grade 1 edema indicates a clinically concerning threshold.
Current monitoring includes standardized eye examinations and MRI before and after missions.
No established therapy exists for SANS beyond refractive correction and return to Earth.
Potential countermeasures include lower body negative pressure and venoconstrictive thigh cuffs.

Clinical Implications

The consensus emphasizes the importance of standardized diagnosis and monitoring for SANS.

Conclusion

SANS represents an emerging challenge in neuro-ophthalmology as space missions extend in duration. Continued research and standardized protocols are essential for safeguarding astronaut ocular health.