AS-OCT与A超测量中央角膜厚度与前房深度的比较

目的 探讨眼前段光学相干断层扫描技术(anteriorsegment optical coherence tomography,AS-OCT)和A型超声波生物测量技术(A超)测量,中央角膜厚度(central corneal thickness,CCT)和前房深度(anterior chamber depth,ACD)的异同.方法 分别采用AS-OCT和A超测量33名(54只眼)正常人的CCT和ACD,分别采用配对t检验、Pearson相关和Bland-Altman方法,分析两种仪器的测量值的差异、相关性和一致性.结果 A超与AS-OCT的CCT值分别为(524.41±23.24)μm、(513.37±22.71)μm,之间的差异有统计学意义(t=15.906,P=0.000),差值均数为(11.04±5.10)μm.两种仪器的CCT值正相关(r=0.976,P=0.000).95%LoA(95% Limts of Agreement)为(-21.03,-1.04)μm,95%LoA的区间范围为19.99μm,为A超CCT平均值的3.81%.A超与AS-OCT的ACD值分别为(2.89±0.29)mm、(3.18±0.26)mm,之间的差异有统计学意义(f=-12.052,P=0.000),差值的均数为(-0.29±0.17)mm.两种仪器的ACD值相关(r=0.803,P=0.000).95%LoA为(-0.63,-0.06)mm,95%LoA的区间范围为0.57mm,为A超ACD平均值的19.72%.结论 AS-OCT的CCT值和ACD值与A超的测量值相关.与A超相比,AS-OCT的CCT测量值更小,而ACD值更大.两种仪器测量CCT的一致性比ACD高.

Comparison of central corneal thickness and anterior chamber depth measurements using the Anterior Segment Optical Coherence Tomography and A-scan ultrasonography

Objective To assess central corneal thickness(CCT)and anterior chamber depth (ACD) measurements with anterior segment optical coherence tomography (AS-OCT)comparing with A-scan ultrasonography (A-scan US).Methods 54 eyes of 33 normal subjects were enrolled in the study.CCT and ACD were measured using AS-OCT and A-scan US.The measurements of two instruments were analyzed using paired t test,Pearson correlation and Bland-Altman plot,respectively.Results The CCT of AS-OCT and A-scan US were 524.41± 23.24 microm and 513.37± 22.7 microm,respectively.The CCT values measured by A-scan US were significantly greater than AS-OCT, paired difference was 11.04± 5.10 microm (t =15.906, P =0.000).There were a significantly correlation between CCTs value of two instruments (r =0.976, P =0.000). The 95% LoA (95% Limts of Agreement)was -21.03 microm to -1.04 microm.The width of 95% LoA was 28 microm,3.81% of the average pachymetry reading.The ACD of AS-OCT and A-scan US were 2.89± 0.29 mm and 3.18 ± 0.26 mm,respectively.The ACD values measured by AS-OCT were significantly greater than A-scan US, paired difference was -0.29± 0.17 mm(t =-12.052, P = 0.000).There were a significantly correla-tion between CCTs value of two instruments(r=0.803 ,P=0.000).The 95% LoA was -0.63 mm to -0.06 mm.The width of 95% LoA was 0.57 mm, 19.72% of the average A-scan reading.Conclusion CCT and ACD measured by AS-OCT were highly correlated with that from ultrasound pachymetry.ln comparison with measurements of A-scan,CCT value of AS-OCT was lower,and the ACD was deeper.However,ACD readings by AS-OCT and A-scan were consistently less than that of CCT.