频域光学相干断层扫描测量正常人中央角膜厚度的可重复性研究

Reproducibility of the measurement of central corneal thickness of normal persons with spectral-domain optical coherence tomography

目的评估频域光学相干断层扫描(SD-OCT)测量正常人中央角膜厚度(CCT)的可重复性。方法随机选取正常人50例共50眼,应用SD-OCT测量CCT,扫描深度为2.0 mm,光源波长为840 nm,轴向分辨率为6μm,横向分辨率为20μm,用系统自带标尺测量角膜顶点前表面到后表面的垂直距离,记录CCT,评估重复性。结果同一观察者测量方法的相关系数(ICC)为0.9558(95%CI:0.925~0.978),变异系数(CV)为2.5%。不同观察者测量方法的ICC为0.9335(95%CI:0.912~0.966),CV为4.8%。观察者1第1次测量的CTT值为(538.53±32.37)μm,第2次为(543.5.25±32.85)μm,差异无统计学意义(P>0.05)。观察者2测量的CCT为(524.53±28.37)μm,与观察者1两次测量的结果比较差异均有统计学意义(P<0.05或0.01)。结论 SD-OCT测量正常人CCT的可重复性高;应用SD-OCT追踪CCT的变化时,应该由同一检测者进行测量。

Objective To evaluate the reproducibility of the measurement of central corneal thickness (CCT) of normal persons with spectral-domain optical coherence tomography (SD-OCT). Methods A total of 50 eyes of 50 normal persons were selected, and their CCTs were measured using SD-OCT. The scanning depth was 2.0 mm, the light source wavelength was 840 nm, the axial resolution was 6 μm, and the lateral resolution was 20 μm. The vertical distance from the front surface to the rear surface of the corneal vertex was measured with the ruler of the system, and CCT was recorded to evaluate repeatability. Results The ICC of intraobserver measurement method was 0.9558 (95% CI:0.925-0.978), and the CV of intraobserver measurement method was 2.5%. The ICC of interobserver measurement method was 0.9335 (95% CI:0.912- 0.966), and the CV of intraobserver measurement method was 4.8%. The CTT of the first measurement by Observer 1 was (538.53±32.37)μm, and that of the second measurement by Observer 1 was (543.5.25±32.85)μm, and there was no statistical difference (P>0.05). The CCT measured by Observer 2 was (524.53±28.37)μm, which was statistically different from the results of two measurements by Observer 1 (P<0.05 or 0.01). Conclusion The reproducibility of CCT measurements using SD-OCT is high. The measurement shall be done by the same observer when SD-OCT is used to track the change in CCT.