Optic nerve sheath diameter and spaceflight: defining shortcomings and future directions

Dylan A Fall; Andrew G Lee; Eric M Bershad; Larry A Kramer; Thomas H Mader; Jonathan B Clark; Mohammad I Hirzallah

doi:10.1038/s41526-022-00228-1

Optic nerve sheath diameter and spaceflight: defining shortcomings and future directions

NPJ Microgravity. 2022 Oct 6;8(1):42. doi: 10.1038/s41526-022-00228-1.

Authors

Dylan A Fall¹, Andrew G Lee^{2

3

4

5

6

7}, Eric M Bershad^{1

8}, Larry A Kramer⁹, Thomas H Mader¹⁰, Jonathan B Clark¹, Mohammad I Hirzallah^{11

12}

Affiliations

¹ Baylor College of Medicine and The Center for Space Medicine, Houston, TX, USA.
² Department of Ophthalmology, Blanton Eye Institute, Houston Methodist Hospital, Houston, TX, USA.
³ Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, USA.
⁴ Department of Ophthalmology, Weill Cornell Medicine, New York, NY, USA.
⁵ Department of Ophthalmology, University of Texas Medical Branch, Galveston, TX, USA.
⁶ University of Texas MD Anderson Cancer Center, Houston, TX, USA.
⁷ Texas A and M College of Medicine, Bryan, TX, USA.
⁸ Department of Neurology, Baylor College of Medicine, Houston, TX, USA.
⁹ Department of Diagnostic and Interventional Imaging, University of Texas Health Science Center, Houston, USA.
¹⁰ US Army, Moab, UT, USA.
¹¹ Baylor College of Medicine and The Center for Space Medicine, Houston, TX, USA. mohammad.hirzallah@bcm.edu.
¹² Department of Neurology, Baylor College of Medicine, Houston, TX, USA. mohammad.hirzallah@bcm.edu.

Abstract

Neuro-ocular changes during long-duration space flight are known as spaceflight-associated neuro-ocular syndrome (SANS). The ability to detect, monitor, and prevent SANS is a priority of current space medicine research efforts. Optic nerve sheath diameter (ONSD) measurement has been used both terrestrially and in microgravity as a proxy for measurements of elevated intracranial pressure. ONSD shows promise as a potential method of identifying and quantitating neuro-ocular changes during space flight. This review examines 13 studies measuring ONSD and its relationship to microgravity exposure or ground-based analogs, including head-down tilt, dry immersion, or animal models. The goal of this correspondence is to describe heterogeneity in the use of ONSD in the current SANS literature and make recommendations to reduce heterogeneity in future studies through standardization of imaging modalities, measurement techniques, and other aspects of study design.

Publication types

Review