Thickness and birefringence of healthy retinal nerve fiber layer tissue measured with polarization-sensitive optical coherence tomography
Thickness and birefringence of healthy retinal nerve fiber layer tissue measured with polarization-sensitive optical coherence tomography
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DOI：
10.1167/iovs.03-1160
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发表时间：
2004-08-01
影响因子：
4.4
通讯作者：
de Boer, JF
中科院分区：
文献类型：
--
作者：
Cense, B;Chen, TC;de Boer, JF
目的。视网膜神经纤维层变薄以及视网膜神经纤维层（RNFL）双折射的变化可能都先于临床可检测到的青光眼性视力丧失。早期检测RNFL的变化可能使治疗能够预防永久性视力丧失。偏振敏感光学相干断层扫描（PS - OCT）能够提供有关RNFL厚度和双折射的客观信息。
方法。对两名健康年轻志愿者的视神经乳头（ONH）周围进行PS - OCT扫描，采用10个半径逐渐增大的同心圆。通过数据分析确定每个圆上48个扇区的平均RNFL厚度和平均视网膜神经纤维双折射。
结果。RNFL厚度和双折射都随着ONH周围扇区的不同而变化。RNFL随着离ONH距离的增加而变薄。相比之下，双折射作为半径的函数没有显著变化。
结论。健康RNFL的双折射作为扫描半径的函数是恒定的，但随着ONH周围位置的不同而变化，在ONH上方和下方出现较高的厚度值。在ONH周围每单位深度测量的双程相位延迟在0.10到0.35度/微米之间，在840纳米波长下测量时，分别相当于1.2×10⁻⁴和4.1×10⁻⁴的双折射。因此，当假设ONH周围双折射在空间上是恒定的时，将扫描激光偏振测量（SLP）相位延迟测量值转换为RNFL厚度可能会得出错误的值。这些数据并没有否定相位延迟测量的临床价值，但会影响相位延迟到RNFL厚度的转换。
PURPOSE. Thinning of the retinal nerve fiber layer and changes in retinal nerve fiber layer (RNFL) birefringence may both precede clinically detectable glaucomatous vision loss. Early detection of RNFL changes may enable treatment to prevent permanent loss of vision. Polarization-sensitive optical coherence tomography (PS-OCT) can provide objective information on RNFL thickness and birefringence.METHODS. PS-OCT scans around the optic nerve head (ONH) of two healthy young volunteers were made using 10 concentric circles of increasing radius. Both the mean RNFL thickness and mean retinal nerve fiber birefringence for each of 48 sectors on a circle were determined with data analysis.RESULTS. Both the RNFL thickness and birefringence varied as a function of sector around the ONH. The RNFL became thinner with increasing distance from the ONH. In contrast, the birefringence did not vary significantly as a function of radius.CONCLUSIONS. Birefringence of healthy RNFL is constant as a function of scan radius but varies as a function of position around the ONH, with higher thickness values occurring superior and inferior to the ONH. Measured double-pass phase retardation per unit depth around the ONH ranged between 0.10 and 0.35 deg/mum, equivalent to birefringences of 1.2 x 10(-4) and 4.1 x 10(-4) respectively, measured at a wavelength of 840 nm. Consequently, when a spatially constant birefringence around the ONH is assumed, the conversion of scanning laser polarimetry (SLP) phase-retardation measurements to RNFL thickness may yield incorrect values. The data do not invalidate the clinical value of a phase-retardation measurement, but affect the conversion of phase retardation to RNFL thickness.