新型彩色LED角膜分析仪Cassini测量角膜曲率及计算人工晶状体度数的准确性

目的：评估新型角膜分析仪Cassini测量角膜曲率和角膜散光的重复性，及其与人工晶状体生物测量仪IOLMaster的一致性。进一步分析该设备在IOL度数计算上的精确性。方法：本研究共纳入了77例白内障患者的77眼。由一名操作者使用Cassini角膜分析仪和IOLMaster生物测量仪分别测量患者角膜曲率和角膜散光相关参数各3次，包括平坦角膜曲率(Kf)、陡峭角膜曲率(Ks)、角膜散光(Ast)、总角膜屈光力(TCP)和总角膜散光(TCA)。采用组内标准差(Sw)、重测度(TRT)和组内相关系数(ICC)评估数据的重复性。采用Bland-Altman图和95%一致性区间(LoA)评估一致性。通过比较术后3个月IOLMaster和Cassini使用4种不同IOL计算公式时的平均绝对预测误差(MAE)和术后误差分布范围进一步分析Cassini预测IOL度数的准确性。结果：Cassini测量Kf、Ks和TCP的TRT值均≤0.55 D，且ICC值均≥0.966。在散光相关参数方面，Ast的TRT值和ICC值分别为0.47 D和0.973,TCA的TRT值和ICC值分别为0.75 D和0.953...

The precision of novel color LED corneal analyzer Cassini in measuring corneal curvature and intraocularlens power calculation

Objective: To evaluate the repeatability and agreement of novel corneal analyzer Cassini in measuring corneal curvature and corneal astigmatism with IOLMaster analyzer with an analysis of the prediction of Cassini in intraocular lens power calculation. Methods: This prospective comparative study included 77 eyes of 77 patients. One experienced operator measured corneal parameters using Cassini and IOLMaster three times, including the flattest keratometry (Kf), the steepest keratometry (Ks), astigmatism (Ast), total corneal power (TCP), total corneal astigmatism (TCA) and vector analysis of astigmatism (J0, J45). The within-subject standard deviation (Sw), test-retest repeatability (TRT), and intraclass correlation coefficient (ICC) were used to assess repeatability. The agreement between Cassini and IOLMaster was achieved by Bland-Altman plots and 95% limits of agreement (LoA). The mean absolute error (MAE) of different devices and subjective refraction was calculated after a 3-month follow-up period to analyze the precision of intraocular lens (IOL) power calculation. Results: The TRT of Kf, Ks and TCP measured by Cassini were less than 0.55 D, and the ICC values were more than0.995. The TRT and ICC were 0.47 D and 0.973 for astigmatism, respectively. The TRT and ICC of TCA were 0.75 D and 0.953, respectively. All the TRT values were less than 0.48 D and ICC values were more than 0.893 for J0, J45, J0-TCA and J45-TCA. The MAE values of Cassini and IOLMaster were both lower than 0.43 D with four different IOL calculation formulas. The percentages of eyes within ±0.25 D, ±0.50 D, ±0.75 D and ±1.00 D of prediction error were all greater than 28%, 62%, 85% and 94% with different IOL calculation formulas. Conclusion: The novel corneal analyzer Cassini in measuring corneal curvature and corneal astigmatism had fantastic repeatability except TCA. The corneal curvature parameters revealed good agreement in Ks and Kf with IOLMaster and could be used interchangeably. In prediction error, the Cassini had similar precision with IOLMaster that makes it suitable for application inIOLcalculation