Woodman Emily C, Read Scott A, Collins Michael J
Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Australia.
Vision Res. 2012 Nov 1;72:34-41. doi: 10.1016/j.visres.2012.09.009. Epub 2012 Sep 24.
The time course of elongation and recovery of axial length associated with a 30min accommodative task was studied using optical low coherence reflectometry in a population of young adult myopic (n=37) and emmetropic (n=22) subjects. Ten of the 59 subjects were excluded from analysis either due to inconsistent accommodative response, or incomplete anterior biometry data. Those subjects with valid data (n=49) were found to exhibit a significant axial elongation immediately following the commencement of a 30min, 4 D accommodation task, which was sustained for the duration of the task, and was evident to a lesser extent immediately following task cessation. During the accommodation task, on average, the myopic subjects exhibited 22±34μm, and the emmetropic subjects 6±22μm of axial elongation, however the differences in axial elongation between the myopic and emmetropic subjects were not statistically significant (p=0.136). Immediately following the completion of the task, the myopic subjects still exhibited an axial elongation (mean magnitude 12±28μm), that was significantly greater (p<0.05) than the changes in axial length observed in the emmetropic subjects (mean change -3±16μm). Axial length had returned to baseline levels 10min after completion of the accommodation task. The time for recovery from accommodation-induced axial elongation was greater in myopes, which may reflect differences in the biomechanical properties of the globe associated with refractive error. Changes in subfoveal choroidal thickness were able to be measured in 37 of the 59 subjects, and a small amount of choroidal thinning was observed during the accommodation task that was statistically significant in the myopic subjects (p<0.05). These subfoveal choroidal changes could account for some but not all of the increased axial length during accommodation.
在一群年轻的成年近视者（n = 37）和正视者（n = 22）中，使用光学低相干反射测量法研究了与30分钟调节任务相关的眼轴长度伸长和恢复的时间过程。59名受试者中有10名因调节反应不一致或前节生物测量数据不完整而被排除在分析之外。发现那些有有效数据的受试者（n = 49）在开始30分钟、4D的调节任务后立即出现明显的眼轴伸长，这种伸长在任务持续期间持续存在，并且在任务停止后立即在较小程度上仍然明显。在调节任务期间，近视受试者平均眼轴伸长22±34μm，正视受试者平均眼轴伸长6±22μm，然而近视和正视受试者之间的眼轴伸长差异无统计学意义（p = 0.136）。任务完成后立即，近视受试者仍表现出眼轴伸长（平均幅度12±28μm），显著大于正视受试者观察到的眼轴长度变化（平均变化-3±16μm）（p<0.05）。眼轴长度在调节任务完成后10分钟恢复到基线水平。近视者从调节引起的眼轴伸长中恢复的时间更长，这可能反映了与屈光不正相关的眼球生物力学特性的差异。59名受试者中有37名能够测量黄斑下脉络膜厚度的变化，在调节任务期间观察到少量脉络膜变薄，这在近视受试者中具有统计学意义（p<0.05）。这些黄斑下脉络膜变化可以解释调节期间眼轴长度增加的部分但不是全部原因。
