Pentacam、iTrace和OrbscanⅡz测量近视眼角膜前表面Q值和屈光力的一致性

摘要

Objective To compare the myopic anterior corneal surface measurements of the Q value and corneal power provided by Pentacam,iTrace and Orbscan Ⅱ z and evaluate the agreement among the 3 methods.Methods This was a cross-sectional study.One hundred eyes were chosen from 100 myopic patients and the Q value and mean Sim K of the anterior corneal surface was measured by Pentacam,iTrace and Orbscan Ⅱ z in the same patient's eye.Measurement results were compared using analysis of variance and agreement among the measurements was assessed using Bland-Altman plots.Results The Q value measurements were-0.090.12,-0.09±0.09,and-0.18±0.10 with Pentacam,iTrace and Orbscan Ⅱ z,respectively.The Q value measurements with Orbscan Ⅱ z were lower than those with Pentacam and iTrace (F=43.06,P＜0.01).For the Q value measurements,the 95％ limits of agreement (LoA) was small between iTrace and Orbscan Ⅱz (from-0.08 to 0.26)and the 95％ LoA was large between iTrace and Pentacam (from-0.23 to 0.23).The respective mean Sim K measurements were 43.34±1.37 D,43.30±1.35 D and 43.56±1.36 D with Pentacam,iTrace and Orbscan Ⅱ z.The mean Sim K measurements with Orbscan Ⅱ z were greater than that with Pentacam and iTrace (F=23.25,P＜0.01).For the mean Sim K measurements,the 95％ LoA was small between iTrace and Pentacam (from-0.68 to 0.59 D) and the 95％ LoA was large between iTrace and Orbscan Ⅱz (from-1.15 D to 0.63 D).Conclusion Measurements of Q value and mean Sim K of the anterior corneal surface of myopes showed statistically significant differences among the 3 instruments.The agreement among the 3 instruments was not comparable for Q value measurements.The agreement between iTrace and Pentacam had comparable results for mean Sim K,and can refer to one another.%目的 比较Pentacam、iTrace和OrbscanⅡz测量近视眼角膜前表面Q值和屈光力的差异,评估3种方法的一致性.方法 横断面研究.选择100例(100眼)近视患者.用Pentacam、iTrace和OrbscanⅡz测量同一患者角膜前表面的Q值和平均Sim K值.用方差分析来比较测量结果,用Bland-Altman法评价测量的一致性.结果 Pentacam、iTrace和OrbscanⅡz测得Q值分别为-0.09±0.12、-0.09±0.09和-0.18±0.10,OrbscanⅡz测得到Q值比Pentacam和iTrace负值更大(F=43.06,P＜0.01).Q值测量中,iTrace和OrbscanⅡz比较,95％一致性界限较窄,为-0.08～0.26; iTrace和Pentacam比较,95％一致性界限较宽,为-0.23～0.23.Pentacam、iTrace和OrbscanⅡz测得平均Sim K值分别为(43.34±1.37)D、(43.30±1.35)D和(43.56±1.36) D; OrbscanⅡz测量平均Sim K值比Pentacam和iTrace略大,差异有统计学意义(F=23.25,P＜0.01).平均SimK测量中,iTrace和Pentacam比较,95％一致性界限较窄,为-0.68～0.59 D; iTrace和OrbscanⅡz比较,95％一致性界限较宽,为-1.15～0.63 D.结论 Pentacam 、iTrace和orbscanⅡz测量近视眼角膜前表面Q值和平均SimK值有差别.测量Q值时3种仪器一致性较差;测量平均SimK值时Pentacam和iTrace一致性较好,可以互相参考.