Sirius角膜地形图仪与角膜曲率仪测量LASIK术前患者角膜曲率的一致性研究

Consistency in measuring corneal curvature with Sirius corneal topography and a keratometer

目的研究Sirius角膜地形图仪和角膜曲率仪测量准分子激光原位角膜磨镶术（LASIK）前近视患者角膜曲率的一致性。方法前瞻性对照研究。选取绍兴市人民医院门诊近视患者85例（170眼），分别采用Sirius角膜地形图仪和角膜曲率仪对其角膜曲率进行测量。采用配对样本t检验及Pearson直线相关进行统计学分析．并应用Bland—Ahman分析评价两种测量方法的一致性。结果Sirius角膜地形图仪和角膜曲率仪测量角膜曲率K1值分别为（42．41±1．25）D和（42．33±1．28）D，角膜曲率K2值分别为（43．36±1．36）D和（43．56±1．38）D，平均角膜曲率值[（KI＋K2）／2]分别为（42．88＋1．28）D和（42．92±1．29）D，两种仪器测量角膜曲率值差异有统计学意义（t1=5．241，P〈0．01；t2=-9．936，P〈0．01；t均=-3．021，P〈0．01）；两种仪器在测量角膜曲率时呈正相关（r1=0．989，P〈0．01；r2=0．981，P〈0．01；r均=0．990，P〈0．01）；Sirius角膜地形图仪和角膜曲率仪测得的角膜曲率K1值、K2值及平均角膜曲率差值的均数d分别为0．08D，-0．20D和-0．04D，差值的标准差S。分别为0．1897D，0．2644D和0．1790D，95％一致性界限分别为0．45～0．30D，0．32～-0．72D和0．31—0．39D，分别有2．4％（4／170），3．5％（6／170）和4．7％（8／170）的点在95％一致性界限以外，且一致性界限内的最大差值分别为0．44D，0．68D和0．38D。结论Sirius角膜地形图仪和角膜曲率仪在测量近视患者的角膜曲率时有较好的一致性．其值可相互替代使用。

Objective To explore the differences and agreements between Sirius corneal topography and a keratometer in the measurement of corneal curvature before laser in situ keratomileusis （LASIK） in patients with myopia. Methods This was a prospective control study. One hundred and seventy eyes of 85 patients with myopia were selected at The People＇s Hospital of Shaoxing. Measurements of corneal curvature were taken with both Sirius corneal topography and a keratometer. A paired samples t-test and Pearson linear correlation were used for statistical analysis, and a Bland- Altman analysis was used to evaluate the consistency of the two methods of measurement. Results The corneal curvature K1 values measured by Sirius corneal topography and a keratometer were 42.41：t：1.25 D and 42.33~1.28 D, K2 values were 43.36~1.38 D and 43.56-＋1.38 D, and （Kl＋K2）/2 values were 42.88-＋1.28 D and 42.92-＋1.29 D, respectively, indicating significant differences （t1=5.241, P〈0.01; t~=-9.936, P〈0.01; t^s~=-3.021, P〈0.01） and significant linear correlations between K1 and K2 （r1=0.989, P〈0.01;r2=0.981, P〈0.01; rave=0.990, P〈0.01）. The differences between Sirius corneal topography and keratometry measurements of corneal curvature for K1 and K2 values and the differences in average corneal curvature （Kl＋K2）/2 were 0.08 D, -0.20 D and -0.04 D, respectively. The differences between standard deviations were 0.1897 D, 0.2644 D and 0.1790 D and the 95% limits of agreement were （0.45 D, -0.30 D）, （0.32 D, -0.72 D） and （0.31 D, -0.39 D）. There were 2.4% （4/170）, 3.5（6/170） and 4.7%（8/170） points for the 95% limits of agreement, and consistency within the bounds of the maximum differences were 0.44 D, 0.68 D and 0.38 D, respectively. Conclusion ,Sirius corneal topography and keratometrv show good agreement in the measurement of corneal curvature in patients with myopia. The values can be used interchangeably.