Orbscan II与Topolyzer测量角膜曲率和散光参数的比较

Comparison of Orbscan H and Topolyzer in the measurement of keratometry and cornealastigmatism

目的比较OrbscanII眼前节分析系统与Topolyzer角膜地形图仪测量角膜曲率和散光参数的差异，并进行一致性评价。方法前瞻性对照研究。由同一检查者分别应用OrbscanII和Topolyzer对50例（50眼）受检者的角膜曲率（K1、K2、Kin）和散光参数（通过矢量公式转换为J0、J45）进行测量。应用配对t检验对2种方法的测量结果进行比较，并应用Bland—Ahman分析方法对2种仪器进行一致性评价。结果OrbscanII和Topolyzer测量K1、K2、Km的平均差值依次为（-0．14±0．22）D、（-0．18±0．29）D和（-0．16±0．23）D，差异均有统计学意义（t=-4．697、-4．516、-5．144，P〈0．01），而J0、J45的平均差值依次为（0．03±0．12）D和（-0．01±0．11）D，差异均无统计学意义（t=1．875、-0．383，P〉0．05）。Bland—Ahman分析显示K1、K2和Km一致性较差，95％LoA的最大绝对值依次为0．57、0．75和0．61D，而J0、J45一致性较好，95％LoA的最大绝对值依次为0．27和0-22D。结论OrbscanII和Topolyzer在测量角膜散光参数方面具有较好的一致性，但在测量角膜曲率参数方面存在一定差异，在临床使用中应针对具体的临床测量目的选择仪器。

Objective To assess the agreement of keratometry and corneal astigmatism measurements by Orbscan II and Topolyzer. Methods In a prospective comparative study, 50 eyes of 50 healthy subjects were measured with the Orbscan II and Topolyzer. Data were analyzed using a paired sample t test and Bland-Airman plots. Results The mean differences of K1, K2, Kin, J0 and J45 measured by Orbscan II and Topolyzer were -0.14±0.22 D, -0.18±0.29 D, -0.16±0.23 D, 0.03_＋0.12 D and -0.01±0.11 D, respectively. There were significant differences between the results of these 2 methods in K1 （t=-4.697, P〈0.01）, K2 （t=-4.516, P〈0.01） and Km （t=-5.144, P〈 0.01）, but not for J0 （t=1.875, P〉0.05） and J45 （t=-0.383, P〉0.05）. A Bland-Ahman analysis showed that the results for the 2 devices were not comparable results for K1, K2 and Km （The largest 95% LoAs were 0.57 D, 0.75 D and 0.61 D, respectively.）, but results were comparable for J0 and J45 （The largest 95% LoAs were 0.27 D and 0.22 D, respectively.）. Conclusion The corneal astigmatism values obtained with Orbsean II were correlated very well with those of the Topolyzer. However, it is important to note in clinical practice that corneal power values acquired by these 2 devices are not directly interchangeable.