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Evaluation of Optic Disc Edema in Long-Duration Spaceflight Crewmembers Using Retinal Photography
William E Valencia1, Sara S Mason, Tyson J Brunstetter
1The University of Texas Medical Branch at Galveston (WV), Galveston, Texas; MEI Technologies Inc (SM), Houston, Texas; NASA Johnson Space Center (TB, WT, MVB), Houston, Texas; KBR (AS), Houston, Texas; The University of Texas Health Science Center at Houston School of Public Health (CS), Houston, Texas; Coastal Eye Associates (CG), Webster, Texas; Department of Ophthalmology (AL), Houston Methodist Hospital, Houston, Texas; Gagarin Research and Test Cosmonaut Training Center (SD, VM), Star City, Russian Federation; Canadian Space Agency (PH), Chapman Space Centre, Longueuil, Canada; Institute of Biomedical Problems (IM), Russian Academy of Science, Moscow, Russian Federation; German Aerospace Center (CS), Cologne, Germany; Department of Ophthalmology (AT-S), Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan; and School of Medicine and Dentistry (SF), Flaum Eye Institute, University of Rochester, Rochester, New York.
The Frisén scale shows variability in grading optic disc edema (ODE) in astronauts, indicating it may miss early signs of spaceflight-associated neuro-ocular syndrome (SANS). A more objective method is needed for astronaut eye health monitoring.
Area of Science:
- Ophthalmology
- Aerospace Medicine
- Neuroscience
Background:
- Astronauts on long-duration spaceflights risk spaceflight-associated neuro-ocular syndrome (SANS).
- Optic disc edema (ODE) is an early SANS indicator, potentially missed by the subjective Frisén scale.
- Assessing ODE reliability is crucial for astronaut health.
Purpose of the Study:
- Determine inter-rater and intra-rater reliability of the Frisén scale for SANS-induced ODE.
- Propose a standardized evaluation process for SANS-induced ODE across space agencies.
Main Methods:
- Retrospective, double-blinded diagnostic study.
- Expert graders assessed preflight and postflight fundus photographs for ODE using the Frisén scale and disc ranking.
- Concordance analysis for grading and ranking.
Main Results:
- Grade 1 ODE identified in 17.35% of crewmembers; higher grades were rare.
- Inter-rater concordance for Frisén grades was 70.99%.
- Intra-rater agreement for Frisén grade and disc ranking was 77.7%.
Conclusions:
- The Frisén scale demonstrates variability in grading SANS-induced ODE.
- Fundoscopy alone may be insufficient for diagnosing SANS due to potential missed early ODE.
- A multimodal, objective surveillance method, possibly including optical coherence tomography, is needed for astronaut ODE monitoring.
