Lenstar LS900测量仪与iTrace视觉功能分析仪测量白内障患者术前Kappa角与Alpha角一致性研究

目的比较Lenstar LS900测量仪与iTrace视觉功能分析仪测量年龄相关性白内障患者术前Kappa角与Alpha角的一致性。方法收集2017年12月至2018年6月在中国医科大学附属第四医院眼科就诊的年龄相关性白内障患者55例(59眼),术前分别应用Lenstar LS900测量仪和iTrace视觉功能分析仪测量以瞳孔为中心的视轴偏心距(Kappa角)和以虹膜为中心的视轴偏心距(Alpha角)。先收集在角膜顶点平面分解的X轴和Y轴坐标,再通过三角函数计算偏心距,最后分别比较X轴、Y轴、瞳孔直径、角膜水平直径、视轴偏心距。两种仪器所测数据的比较采用配对t检验,一致性比较采用Bland-Altman分析。结果 Lenstar LS900测量的Kappa角为(0.270±0.128)mm,Alpha角为(0.349±0.128)mm,瞳孔直径为(4.101±0.773)mm,角膜水平直径(白到白,WTW)为(10.848±0.467)mm,X轴Kappa角为(0.016±0.225)mm,Y轴Kappa角为(0.105±0.185)mm,X轴Alpha角为(0.010±0.353)m...

Comparative study on consistency of Lenstar LS900 and iTrace for measuring Kappa angle and Alpha angle in cataract patients before surgery

Objective To compare the consistency of Lenstar LS900 and iTrace for measuring Kappa angle and Alpha angle in patients with age-related cataract before surgery.Methods From December 2017 to June 2018,55 patients(59 eyes)with age-related cataract were collected from Ophthalmology Department of the Fourth Affiliated Hospital of Chinese Medical University.Before surgery,the pupil centered axis of sight eccentric distance(Kappa angle)and the iris centered axis of sight eccentric distance(Alpha angle)were measured by Lenstar LS900 and iTrace respectively.Firstly,The X-axis and Y-axis coordinates were measured in the iris plane,and then the eccentric distance was calculated by trigonometric function.Finally,the X-axis,Y-axis,pupil diameter,corneal horizontal diameter and axis of sight eccentric distance were compared respectively.The paired t-test was used to compare the data measured by the two instruments.Bland-altman analysis was used for consistency comparison.Results Lenstar LS900 measurement showed that the Kappa angle was(0.270±0.128)mm,the Alpha angle was(0.349±0.128)mm,pupil diameter was(4.101±0.773)mm,corneal horizontal diameter(white to white,WTW)was(10.848±0.467)mm,Kappa angle at X-axis was(0.016±0.225)mm,Kappa angle at Y-axis was(0.105±0.185)mm,Alpha angle at X-axis was(0.010±0.353)mm,and Alpha angle at Y-axis was(0.042±0.195)mm.Measurement by iTrace showed that Kappa angle was(0.296±0.131)mm,Alpha angle was(0.338±0.121)mm,pupil diameter was(4.103±0.797)mm,corneal horizontal diameter(white to white,WTW)was(10.837±0.475)mm,Kappa angle at X-axis was(0.022±0.233)mm,Kappa angle at Y-axis was(0.091±0.172)mm,Alpha angle at X-axis was(0.006±0.345)mm and Alpha angle at Y-axis was(0.029±0.112)mm.There was no significant difference in each data between the two instruments(all P>0.05).Bland-Altman analysis showed that there was a good consistency of test results between the two instruments.Conclusion There is a good consistency between Lenstar LS900 and iTrace in measuring the Alpha angle and Kappa angle in patients with age-related cataract before surgery,which can provide some reference for the selection of refractive intraocular lens.