Departamento de Oftalmología, Clínica Universitaria, Universidad de Navarra, Pamplona, Spain.
Eye (Lond). 2010 Jun;24(6):1064-70. doi: 10.1038/eye.2009.233. Epub 2009 Sep 25.
To assess the interchangeability of central corneal thickness (CCT) measurements between combined scanning-slit/Placido disc topography (Orbscan-II) and specular microscopy (Topcon SP-2000P) in patients who underwent laser in situ keratomileusis (LASIK) for myopia.
We recruited 118 consecutive patients who underwent LASIK for myopia. The CCT was measured using Orbscan-II and Topcon SP-2000P randomly. Orbscan-II and Topcon SP-2000P CCT data were analysed using the paired-sample t-test and the limits of agreement (LoA) were calculated with the method described by Bland-Altman.
The average CCT measurements by Orbscan-II and Topcon SP-2000P were 447.55+/-49.78 microm and 461.38+/-35.35 microm, respectively (P<0.0001; mean difference, 13.83+/-22.31 microm; 95% confidence interval, 9.77-17.09 microm). The Bland-Altman plot showed an inverse association between the average and the difference between the devices: Topcon-Orbscan-II=174.23 -0.353xAverage (P<0.01). The widths of the crude and regression-based 95% limits of agreement were 87.45 and 63.72 microm, respectively.
Orbscan-II measurements of CCT after myopic LASIK were significantly lower than those obtained using Topcon SP-2000P. The limits of agreement between the two devices were too broad and, therefore, both pachymetric values cannot be used interchangeably. Further, the tendency towards comparably Orbscan-II readings in thinner corneas precludes that one technique can directly replace the other. This is important for the adequate medium- and long-term follow-up of the growing LASIK patient population.
评估接受近视 LASIK 手术的患者中，组合扫描-slit/Placido 盘地形图（Orbscan-II）和共焦显微镜（Topcon SP-2000P）测量的中央角膜厚度（CCT）之间的可互换性。
我们招募了 118 例连续接受 LASIK 治疗近视的患者。使用 Orbscan-II 和 Topcon SP-2000P 随机测量 CCT。使用配对样本 t 检验分析 Orbscan-II 和 Topcon SP-2000P 的 CCT 数据，并使用 Bland-Altman 描述的方法计算一致性界限（LoA）。
Orbscan-II 和 Topcon SP-2000P 测量的平均 CCT 分别为 447.55+/-49.78μm 和 461.38+/-35.35μm（P<0.0001；平均差值，13.83+/-22.31μm；95%置信区间，9.77-17.09μm）。Bland-Altman 图显示设备之间的平均值和差异之间存在反向关联：Topcon-Orbscan-II=174.23-0.353xAverage（P<0.01）。粗略和基于回归的 95%一致性界限的宽度分别为 87.45μm 和 63.72μm。
近视 LASIK 后 Orbscan-II 测量的 CCT 明显低于使用 Topcon SP-2000P 获得的 CCT。两种设备之间的一致性界限太宽，因此，两种角膜厚度值不能互换使用。此外，较薄角膜中 Orbscan-II 读数的可比性趋势排除了一种技术可以直接替代另一种技术。这对于 LASIK 患者群体的充分中期和长期随访非常重要。
