PURPOSE To compare the accuracy of different corneal astigmatism values measured by Scheimpflug keratometry (Pentacam), including Simulated Keratometry (SimK) and three total corneal astigmatism values, equivalent K reading (EKR), true net power (TNP), and total corneal refractive power (TCRP). METHODS We enrolled 168 eyes of 168 patients with non-toric IOL implantation. Pentacam examination and subjective refraction were performed 3 months after surgery. The agreement, arithmetic difference, and vector difference between refractive astigmatism (RA) and different corneal astigmatism values were compared. RESULTS Differences in astigmatism magnitude were significant between SimK and RA in the against-the-rule (ATR) and with-the-rule (WTR) groups but not in total corneal measurements. The meridians of SimK and RA differed significantly in the oblique astigmatism group. The correlations between total corneal astigmatism values and RA were stronger than that between SimK and RA in the total, WTR, and oblique astigmatism groups in Pearson's correlation test. Bland-Altman plots revealed more data points exceeding the limits of agreement (LoA) in SimK measurement in total and WTR subjects. In the ATR group, fewer data points exceeded LoA in EKR. The mean difference vector between SimK and RA was larger than that of other measurements in each astigmatism group. The arithmetic mean of difference vector was significantly smaller in EKR in the total, WTR, and oblique groups. CONCLUSIONS Among different Pentacam readings, corneal astigmatism measurements considering anterior and posterior corneal surfaces were more representative of total ocular astigmatism than SimK, and EKR showed markedly better performance in astigmatism estimation.

中文翻译：

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比较非扭转性假晶状体眼中四个Pentacam角膜散光值的准确性。

目的比较Scheimpflug角膜曲率法（Pentacam）测量的不同角膜散光值的准确性，包括模拟角膜散光法（SimK）和三个角膜总散光值，等效K读数（EKR），真实净功率（TNP）和总角膜屈光力（TCRP）。方法我们纳入了168例非扭转性IOL植入患者的168眼。术后3个月进行Pentacam检查和主观验光。比较了屈光散光（RA）和不同角膜散光值之间的一致性，算术差异和向量差异。结果SimK和RA在规则规则（ATR）和规则规则（WTR）组中的散光幅度差异显着，但在总的角膜测量结果中差异不大。SimK和RA的子午线在斜散光组中有显着差异。在皮尔逊相关检验中，总，WTR和斜散光组中，总角膜散光值与RA之间的相关性强于SimK和RA之间的相关性。Bland-Altman图显示，在总人数和WTR受试者中，SimK测量中的数据点超过了协议限制（LoA）。在ATR组中，在EKR中超过LoA的数据点更少。SimK和RA之间的平均差异向量大于每个散光组中其他测量的平均差异向量。在EKR总数，WTR和倾斜组中，差异向量的算术平均值均显着较小。结论在不同的Pentacam读数之间，