Ultrasound Biomicroscopy as a Novel, Potential Modality to Evaluate Anterior Segment Ophthalmic Structures during Spaceflight: An Analysis of Current Technology

Abstract

Ocular health is currently a major concern for astronauts on current and future long-duration spaceflight missions. Spaceflight-associated neuro-ocular syndrome (SANS) is a collection of ophthalmic and neurologic findings that is one potential physiologic barrier to interplanetary spaceflight. Since its initial report in 2011, our understanding of SANS has advanced considerably, with a primary focus on posterior ocular imaging including fundus photography and optical coherence tomography. However, there may be changes to the anterior segment that have not been identified. Additional concerns to ocular health in space include corneal damage and radiation-induced cataract formation. Given these concerns, precision anterior segment imaging of the eye would be a valuable addition to future long-duration spaceflights. The purpose of this paper is to review ultrasound biomicroscopy (UBM) and its potential as a noninvasive, efficient imaging modality for spaceflight. The analysis of UBM for spaceflight is not well defined in the literature, and such technology may help to provide further insights into the overall anatomical changes in the eye in microgravity.

Keywords: space medicine; spaceflight associated neuro-ocular syndrome (SANS); ultrasound biomicroscopy (UBM).

Figure 1

Ultrasound biomicroscopy (UBM) of the anterior segment of the eye showcasing various metrics including anterior chamber length (ACD), trabecular-meshwork ciliary process angle (TCPA), scleral ciliary process angle (SCPA), and trabecular iris angle (TIA). These anterior segment metrics are quantifiable to monitor during spaceflight. Reprinted with permission from [15] under Creative Commons License (https://creativecommons.org/licenses/by/4.0/legalcode.en (accessed on 1 February 2024)).