两种不同原理的眼前节分析仪在飞秒激光小切口角膜基质透镜取出术后角膜测量中的比较

Comparison of swept source optical coherence tomography and Scheimpflug imaging in corneal parameter measurement after femtosecond small-incision lenticule extraction

目的 比较基于扫频源光学相干层析成像(SS-OCT)原理及Scheimpflug成像原理的眼前节分析仪在飞秒激光小切口角膜基质透镜取出术(SMILE)后角膜测量中的差异性、相关性及一致性。方法 横断面研究。纳入2020年12月~2021年2月期间,就诊于首都医科大学附属北京同仁医院眼科屈光中心门诊、并行SMILE手术的近视患者89例(89眼)为研究对象。分别采用CASIA2和Pentacam在术后3个月屈光稳定状态下,测量其拟合角膜屈光力、后表面角膜屈光力、全角膜屈光力的陡峭轴Ks、平坦轴Kf及平均值Km,测量其中央角膜厚度(CCT)及最薄点角膜厚度(TCT)。采用配对t检验比较2种仪器测量结果间的差异性。采用Pearson相关分析评价2种仪器测量结果间的相关性。采用Bland-Altman法评价2种仪器测量结果的一致性。结果 89例(89眼)患者中,男性27例、女性62例,年龄(28±6)岁。CASIA2测量的平均拟合角膜屈光力、后表面角膜屈光力、全角膜屈光力分别为(39.18±1.52)D、(-6.23±0.24)D、(37.52±1.53)D,CCT、TCT为(438.73±26.04)μm、(434.56±26.12)μm。Pentacam测量的平均拟合角膜屈光力、后表面角膜屈光力、全角膜屈光力分别为(38.99±1.53)D、(-6.30±0.25)D、(37.44±1.58)D,CCT、TCT为(444.17±25.83)μm、(441.90±25.99)μm。以上参数的测量差异均有统计学意义(P<0.05)。相关性分析显示,2种设备测量结果均呈显著正相关(r=0.975~0.989,P值均<0.01)。Bland-Altman分析显示,2种设备测量结果 95%一致性界限线外点分布概率在3.37%~6.74%。结论 在SMILE术后患者的角膜测量中,CASIA2测量的拟合角膜屈光力、全角膜屈光力较Pentacam测量结果更为陡峭,CASIA2测量的后表面角膜屈光力较Pentacam测量结果更为平坦,CASIA2测量的角膜厚度较Pentacam测量结果更薄。虽然2种仪器结果具有显著相关性,但二者不可替代使用。

Objective To investigate the difference, correlation, and agreement of anterior segment analyzers based on the principles of swept source optical coherence tomography(SS-OCT) and Scheimpflug imaging in the measurement of corneal parameter after femtosecond small-incision lenticule extraction(SMILE). Methods Cross-sectional study. From December 2020 to February 2021, 89 ametropia patients(89 eyes) who underwent SMILE in the outpatient department of the Eye Refractive Center, Beijing Tongren Hospital Affiliated to the Capital Medical University, were included in the study. CASIA2 and Pentacam were used three months postoperatively to measure the fitted corneal refractive power, posterior corneal curvature,total corneal refractive in terms of keratometry steep(Ks), keratometry flat(Kf) and mean keratometry(Km),as well as the central corneal thickness(CCT) and the thinnest corneal thickness(TCT). Paired t-test was used to compare the differences between the measurements of the two instruments and Pearson’s correlation analysis for the correlation between them. The Bland-Altman method was used to evaluate the agreement of the measurement results of the two instruments. Results Among the 89 patients(89 eyes), there were 27 males and 62 females, aged(28±6) years. The fitted corneal refractive power, posterior corneal curvature and total corneal refraction measured by CASIA2 were(39.18±1.52)D,(-6.23±0.24)D and(37.52±1.53)D, respectively.And CCT and TCT were(438.73±26.04) μm,(434.56±26.12) μm, respectively. Those measured by Pentacam were(38.99±1.53)D,(-6.30 ± 0.25) D,(37.44 ± 1.58) D,(444.17±25.83) μm, and(441.90±25.99)μm, respectively. The parameters had significant differences(P<0.05). Correlation analysis showed that the measurements of the two devices were significantly positively correlated(r =0.975-0.989, both P<0.01). BlandAltman analysis showed that the probability of distribution of points outside the boundary line of 95% limits of agreement between the measurements of the two devices ranged from 3.37% to 6.74%. Conclusions In the corneal parameter measurements of patients after SMILE, both the fitted and total corneal refractive power measured by CASIA2 were steeper than those measured by Pentacam, the post corneal curvature measured by CASIA2 was flatter than that measured by Pentacam, and the corneal refractive power measured by CASIA2was flatter than that measured by Pentacam. The thickness measured by CASIA2 was thinner than that measured by Pentacam. Although the results of the two instruments were significantly correlated, they were irreplaceable.