Epsom and St Helier University Hospitals NHS Trust, London, United Kingdom.
J Cataract Refract Surg. 2011 Feb;37(2):295-301. doi: 10.1016/j.jcrs.2010.08.050.
To compare the mean keratometry (K) readings obtained with a conventional automated keratometer (IOLMaster) and a Scheimpflug keratometer (Pentacam) in eyes having preoperative assessment for routine cataract surgery.
Epsom and St. Helier University Hospitals, London, United Kingdom.
Evaluation of diagnostic technology.
Mean K values were obtained with the conventional and Scheimpflug keratometers. The following Scheimpflug readings were evaluated: anterior K, true net power, and Holladay equivalent K measured at 1.0 to 7.0 mm corneal diameters. Mean readings for each type of keratometry were compared. Bland-Altman plots were used to determine the 95% limits of agreement (LoA) for the conventional and Scheimpflug keratometers.
The mean conventional K was statistically significantly greater than the mean Scheimpflug K for true net power and equivalent K at 1.0 mm, 2.0 mm, 3.0 mm, and 4.0 mm corneal diameters. The mean conventional K was significantly less than the equivalent K at 5.0 mm, 6.0 mm, and 7.0 mm. The smallest mean difference was for equivalent K at 4.5 mm (0.02 diopters [D]). The smallest 95% LoA were -0.68 to 1.16 D (equivalent K at 5.0 mm) and -0.91 to 0.95 D (equivalent K at 4.5 mm).
Overall, the equivalent K at 4.5 mm had the closest match with the conventional K values. The degree of interdevice variability with the conventional keratometer was lowest for the equivalent K at 4.5 mm and 5.0 mm, although this variability would be sufficient to influence intraocular lens power selection.
比较常规自动角膜曲率计（IOLMaster）和Scheimpflug 角膜地形图仪（Pentacam）在接受常规白内障术前评估的眼中测量的平均角膜曲率（K）读数。
英国伦敦埃普索姆和圣赫利尔大学医院。
诊断技术评估。
使用常规和 Scheimpflug 角膜曲率计获得平均 K 值。评估以下 Scheimpflug 读数：前 K 值、真实净力和 1.0 至 7.0 mm 角膜直径处的 Holladay 等效 K 值。比较每种角膜曲率计的平均读数。Bland-Altman 图用于确定常规和 Scheimpflug 角膜曲率计的 95%一致性界限（LoA）。
在 1.0 mm、2.0 mm、3.0 mm 和 4.0 mm 角膜直径处，常规 K 的平均值显著大于 Scheimpflug K 的平均值，用于真实净力和等效 K。在 5.0 mm、6.0 mm 和 7.0 mm 处，常规 K 的平均值显著小于等效 K。等效 K 在 4.5 mm 处的平均差异最小（0.02 屈光度 [D]）。最小的 95%LoA 为 -0.68 至 1.16 D（等效 K 在 5.0 mm）和 -0.91 至 0.95 D（等效 K 在 4.5 mm）。
总体而言，等效 K 在 4.5 mm 处与常规 K 值最匹配。常规角膜曲率计的设备间变异性最小，等效 K 在 4.5 mm 和 5.0 mm 处，尽管这种变异性足以影响人工晶状体功率选择。
