KBR, Houston, Texas.
NASA, Johnson Space Center, Houston, Texas.
JAMA Ophthalmol. 2021 Jul 1;139(7):781-784. doi: 10.1001/jamaophthalmol.2021.1400.
Long-duration spaceflight induces structural changes in the brain and eye. Identification of an association between cerebral and ocular changes could help determine if there are common or independent causes and inform targeted prevention strategies or treatments.
To determine if there is an association between quantitative changes in intracranial compartment volumes and peripapillary total retinal thickness after spaceflight.
DESIGN, SETTING, AND PARTICIPANTS: This cohort study included healthy International Space Station crew members before and immediately after long-duration spaceflight. Data on race were not collected. Analysis was conducted from September to November 2020.
Long-duration spaceflight (mean [SD], 191 [55] days).
Optical coherence tomography-derived peripapillary total retinal thickness as a quantitative assessment and early sign of optic disc edema and magnetic resonance imaging-derived measures of lateral ventricle volume, white matter volume, and whole brain plus cerebrospinal fluid volume.
In 19 healthy crew members included in this study (5 women [26.3%], 14 men [73.7%]; mean [SD] age, 45.2 [6.4] years), analyses revealed a positive, although not definitive, association between spaceflight-induced changes in total retinal thickness and lateral ventricle volume (4.7-μm increase in postflight total retinal thickness [95% CI, -1.5 to 10.8 μm; P = .13] per 1-mL postflight increase in lateral ventricle volume). Adjustments for mission duration improved the strength of association (5.1 μm; 95% CI, -0.4 to 10.5 μm; P = .07). No associations were detected between spaceflight-induced changes in total retinal thickness and white matter volume (0.02 μm; 95% CI, -0.5 to 0.5 μm; P = .94) or brain tissue plus cerebrospinal fluid volume, an estimate of intracranial volume (0.02 μm; 95% CI, -0.6 to 0.6 μm; P = .95).
These results help characterize spaceflight-associated neuro-ocular syndrome and the physiologic associations of headward fluid shifts with outcomes during spaceflight on the central nervous system. The possibly weak association between increased total retinal thickness and lateral ventricle volume suggest that while weightlessness-induced fluid redistribution during spaceflight may be a common stressor to the brain and retina, the development of optic disc edema appears to be uncoupled with changes occurring in the intracranial compartment.
长时间的太空飞行会引起大脑和眼睛的结构变化。确定大脑和眼部变化之间是否存在关联，可以帮助确定是否存在共同或独立的原因，并为有针对性的预防策略或治疗提供信息。
确定太空飞行后颅内容积和视盘周围总视网膜厚度的定量变化之间是否存在关联。
设计、环境和参与者： 这项队列研究纳入了健康的国际空间站机组人员，在长时间太空飞行前后进行了研究。没有收集种族数据。分析于 2020 年 9 月至 11 月进行。
长时间太空飞行（平均[标准差]，191[55]天）。
应用光学相干断层扫描（OCT）测量视盘周围总视网膜厚度，这是视神经盘水肿的早期定量评估指标；应用磁共振成像（MRI）测量侧脑室容积、脑白质容积和全脑加脑脊液容积。
在本研究中，共纳入 19 名健康的机组人员（5 名女性[26.3%]，14 名男性[73.7%]；平均[标准差]年龄为 45.2[6.4]岁），分析结果显示，太空飞行引起的总视网膜厚度变化与侧脑室容积变化之间存在正相关，但并不明确（飞行后总视网膜厚度增加 4.7 μm[95%置信区间，-1.5 至 10.8 μm；P=0.13]，每毫升侧脑室体积增加 1 毫升）。调整飞行任务持续时间可增强关联强度（5.1 μm；95%置信区间，-0.4 至 10.5 μm；P=0.07）。飞行引起的总视网膜厚度变化与脑白质容积（0.02 μm；95%置信区间，-0.5 至 0.5 μm；P=0.94）或脑组织加脑脊液容积（颅内容积的估计值）之间无相关性（0.02 μm；95%置信区间，-0.6 至 0.6 μm；P=0.95）。
这些结果有助于描述与太空飞行相关的神经眼综合征以及头部流体移位与中枢神经系统在太空飞行期间的结果之间的生理关联。总视网膜厚度增加与侧脑室体积之间的关联可能较弱，这表明虽然太空飞行期间的失重引起的流体再分布可能是大脑和视网膜的共同应激源，但视盘水肿的发展似乎与颅内容积变化无关。
