Late developments of optic disc edema or choroidal folds were documented in 2 crew members who had traveled to the International Space Station on a year-long space mission, according to a report published in JAMA Ophthalmology.
The researchers reviewed 2 cases of International Space Station missions that lasted longer than 6 months and their associations with worsening of space-associated neuro-ocular syndrome. The main outcome parameters obtained by optical coherence tomography (OCT) were the minimum marginal width and the total peripapillary retinal thickness, and the participants were tested before, during and after the space flight. Other eye changes observed were peripapillary retinal edema, axial length, anterior chamber depth, and refraction. In its analysis, the study compared eye changes in 2 crew members with cohort crew members from a 6-month mission (n = 11).
In both participants 1 and 2, the study found an increase in the minimum edge width (561 µm and 539 µm on flight day 270) and total retinal thickness (547 µm on flight day 90 and 528 µm on flight day 210) in both 1-year space flight participants during the total duration of spaceflight exposure compared to the maximum observed change compared to the previous flight. These results reflect an increase of 149 µm and 56 µm for the minimum marginal width and 135 µm and 45 µm for the entire retinal thickness. The researchers note that the other eye changes analyzed were similar between the 1-year participants and the 6-month cohort.
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The researchers explain that, while the results of this study support their hypothesis, they may not apply to other participants in a year-long space mission. Because this study only quantifies choroidal folds, it did not collect data on other types of folds that were documented in past space research. In addition, the study emphasized the need to identify the factors that contribute to these eye changes in the future.
“As future space missions are expected to be longer and beyond low earth orbit, further monitoring of astronaut eye health on space missions longer than 6 months may be warranted,” they conclude.
reference
Macias BR, Ferguson CR, Patel N, et al. Changes in the optic nerve head and the choroid over 1 year of space travel. JAMA Ophthalmol. Published online April 29, 2021. doi: 10.1001 / jamaophthalmol.2021.0931
This article originally appeared on Ophthalmology Advisor
