Brown Jamin S, Flitcroft D Ian, Ying Gui-shuang, Francis Ellie L, Schmid Gregor F, Quinn Graham E, Stone Richard A
Kresge Eye Institute, Wayne State University, Detroit, Michigan 48236, USA.
Invest Ophthalmol Vis Sci. 2009 Jan;50(1):5-12. doi: 10.1167/iovs.08-1779. Epub 2008 Aug 21.
The authors applied partial coherence interferometry (PCI) to estimate the thickness of the human choroid in vivo and to learn whether it fluctuates during the day.
By applying signal processing techniques to existing PCI tracings of human ocular axial length measurements, a signal modeling algorithm was developed and validated to determine the position and variability of a postretinal peak that, by analogy to animal studies, likely corresponds to the choroidal/scleral interface. The algorithm then was applied to diurnal axial eye length datasets.
The postretinal peak was identified in 28% of subjects in the development and validation datasets, with mean subfoveal choroidal thicknesses of 307 and 293 microm, respectively. Twenty-eight of 40 diurnal PCI datasets had at least two time points with identifiable postretinal peaks, yielding a mean choroidal thickness of 426 microm and a mean high-low difference in choroidal thickness of 59.5 +/- 24.2 microm (range, 25.9-103 microm). The diurnal choroidal thickness fluctuation was larger than twice the SE of measurement (24.5 microm) in 16 of these 28 datasets. Axial length and choroidal thickness tended to fluctuate in antiphase.
Signal processing techniques provide choroidal thickness estimates in many, but not all, PCI datasets of axial eye measurements. Based on eyes with identifiable postretinal peaks at more than one time in a day, choroidal thickness varied over the day. Because of the established role of the choroid in retinal function and its possible role in regulating eye growth, further development and refinement of clinical methods to measure its thickness are warranted.
作者应用部分相干干涉测量法（PCI）在体内估计人脉络膜厚度，并了解其在一天中是否波动。
通过将信号处理技术应用于现有的用于测量人眼轴长的PCI描记图，开发并验证了一种信号建模算法，以确定视网膜后峰值的位置和变异性，根据动物研究类推，该峰值可能对应脉络膜/巩膜界面。然后将该算法应用于昼夜眼轴长度数据集。
在开发和验证数据集中，28%的受试者识别出视网膜后峰值，分别具有平均中心凹下脉络膜厚度为307和293微米。40个昼夜PCI数据集中的28个至少有两个时间点具有可识别的视网膜后峰值，平均脉络膜厚度为426微米，脉络膜厚度的平均高低差值为59.5±24.2微米（范围为25.9 - 103微米）。在这28个数据集中，有16个昼夜脉络膜厚度波动大于测量标准误（24.5微米）的两倍。眼轴长度和脉络膜厚度倾向于呈反相波动。
信号处理技术在许多但并非所有的眼轴测量PCI数据集中提供脉络膜厚度估计值。基于一天中多次出现可识别视网膜后峰值的眼睛，脉络膜厚度在一天中有所变化。鉴于脉络膜在视网膜功能中的既定作用及其在调节眼球生长中的可能作用，有必要进一步开发和完善测量其厚度的临床方法。
