Svoronos Alexander A, O'Grady Cambria S, Walker Evan, Afshari Natalie A, Macias Brandon R, Laurie Steven S, Weinreb Robert N, Huang Alex S
From the The Shiley Eye Institute, Department of Ophthalmology (A.S., E.W., N.A., R.W., A.H.), University of California San Diego, La Jolla, California, USA.
Aegis Aerospace (C.O.), Houston Texas, USA.
Am J Ophthalmol. 2025 Aug;276:146-156. doi: 10.1016/j.ajo.2025.04.001. Epub 2025 Apr 5.
To study changes in ocular biometry and refraction in the largest cohort to date of astronauts who have experienced long-duration spaceflight on the International Space Station (ISS).
A prospective cohort study.
29 astronauts.
Preflight and postflight cycloplegic refraction and ocular biometry measurements were obtained from 56 eyes among 29 subjects. For each eye, the preflight-to-postflight changes in spherical equivalent (SE), axial length (AL), average corneal curvature (K), and anterior chamber depth (ACD) were calculated. The Fyodorov and Olsen-C formulas were used to estimate the relative contribution of each biometric parameter individually to the total change in SE. A linear mixed-model approach was used to assess the relationships between refraction measurements, biometric parameters, optic disc edema, and duration on the ISS.
Preflight-to-postflight changes in spherical equivalent, axial length, average corneal curvature, and anterior chamber depth.
27/56 (48.2%) eyes underwent a hyperopic shift, 8/56 (14.3%) underwent a myopic shift, and 21/56 (37.5%) eyes had no measurable change in SE. On average, this equated to a mild hyperopic shift of +0.12 D (95% CI, +0.02 to +0.22 D) that arose from a decrease in AL of -0.09 mm (95% CI, -0.14 to -0.04 mm), mitigated by a shortening in ACD of -0.09 mm (95% CI, -0.12 to -0.06 mm). Changes in K were variable and had little contribution to SE changes at the group level but often showed substantial change at the individual level. Statistical modeling revealed the greatest predictor for refractive change was baseline preflight refraction (P = .034), with myopic individuals experiencing the largest hyperopic shifts (and never a myopic shift) and baseline hyperopic individuals experiencing variable myopic to mildly hyperopic shifts.
Spaceflight is associated with decreases in AL and ACD and variable changes in K. On average, these changes result in a mild hyperopic shift in SE, although myopic shifts can be observed at the individual level. Prior reports of greater hyperopic shift may be a result of subjects being more myopic at baseline.
在迄今为止参与国际空间站（ISS）长期太空飞行的最大规模宇航员队列中研究眼生物测量和屈光的变化。
前瞻性队列研究。
29名宇航员。
获取了29名受试者56只眼睛的飞行前和飞行后睫状肌麻痹验光及眼生物测量数据。对于每只眼睛，计算了等效球镜度（SE）、眼轴长度（AL）、平均角膜曲率（K）和前房深度（ACD）从飞行前到飞行后的变化。使用费奥多罗夫公式和奥尔森 - C公式分别估计每个生物测量参数对SE总变化的相对贡献。采用线性混合模型方法评估屈光测量、生物测量参数、视盘水肿和在国际空间站停留时间之间的关系。
等效球镜度、眼轴长度、平均角膜曲率和前房深度从飞行前到飞行后的变化。
56只眼中有27只（48.2%）出现远视偏移，8只（14.3%）出现近视偏移，21只（37.5%）眼睛的SE无明显变化。平均而言，这相当于轻度远视偏移+0.12 D（95%可信区间，+0.02至+0.22 D），这是由于AL减少-0.09 mm（95%可信区间，-0.14至-0.04 mm）引起的，同时前房深度缩短-0.09 mm（95%可信区间，-0.12至-0.06 mm）减轻了这种变化。K的变化各不相同，在组水平上对SE变化的贡献很小，但在个体水平上常常有显著变化。统计模型显示，屈光变化的最大预测因素是飞行前基线验光（P = 0.034），近视个体经历的远视偏移最大（且从未出现近视偏移），而基线远视个体经历的近视到轻度远视的偏移各不相同。
太空飞行与AL和ACD的减少以及K的变化有关。平均而言，这些变化导致SE出现轻度远视偏移，尽管在个体水平上可以观察到近视偏移。先前关于更大远视偏移的报道可能是由于受试者在基线时近视程度更高。
