应用两种设备测量翼状胬肉患者角膜曲率一致性评价

Agreement between two instruments for assessing corneal curvature among patients with pterygium

目的分析Oculus Keratograph眼表综合分析仪与IOLMaster 5.2.1两种仪器测量翼状胬肉患者角膜曲率结果的一致性。方法前瞻性自身对照试验。收集2018年5~9月我院诊断初发性翼状胬肉患者68例(75只眼),采用图像处理和分析软件(Image-Pro Plus V.6.0)测量并计算翼状胬肉面积≤4 mm 2、4.1~7 mm 2、>7.1 mm 2在分别使用眼表综合分析仪与IOLMaster进行角膜曲率(水平角膜曲率K1、垂直角膜曲率K2)测量,比较两种方法测量结果的相关性、一致性及检出率。结果眼表综合分析仪与IOLMaster分别测量翼状胬肉面积≤4 mm 2者的K1平均值(44.40±1.93)D,(44.20±1.90)D,差异无统计学意义(t=1.07,P>0.05),K2平均值(44.36±1.83)D、(44.21±1.69)D,差异无统计学意义(t=1.18,P>0.05),一致性分别r=0.912、0.932,两组设备检出率100%。两组设备测量翼状胬肉面积4.1~7 mm 2,K1平均值分别(45.32±1.73)D、(43.96±1.75)D、差值为(1.39±0.22)D,差异有统计学意义(t=3.07,P<0.05),K2平均值分别(44.72±1.64)D、(44.26±1.91)D、差异无统计学意义(t=-2.24,P>0.05),一致性r=0.611、0.866,两组设备检出率分别为97.33%,100%,差异无统计学意义(χ2=2.014,t>0.248)。两组设备测量翼状胬肉面积>7.1 mm 2,K1平均值分别(44.12±1.93)D、(43.21±2.25)D,差值为(0.91±0.02)D,差异有统计学意义(t=4.07,P<0.01),K2平均值分别(44.24±1.65)D、(45.15±1.41)D,差值为(-0.91±0.34)D,差异有统计学意义(t=-6.272,P<0.01),一致性分别为r=0.732、0.542,两组设备检出率分别为77.33%,98.66%(χ2=16.054,t=0.000)。Bland-Altman分析95%一致性界限K1(-2.241,3.474),K2(-4.170,2.132)。结论眼表综合分析仪与IOLMaster在翼状胬肉面积≤7 mm 2测量角膜曲率相关程度较高,临床上两者间测量的一致性较好,两组设备检出率近乎相同;当翼状胬肉面积>7 mm 2时,两者间测量一致性较差并且IOLMaster检出率更高一些。

Objective To assess the agreement between Oculus keratometer and IOL Master in corneal curvature measurement among patients with pterygium.Methods This prospective case-control trial enrolled 68 patients(75 eyes)with pterygium in our hospital from May 2018 to September 2018.Two instruments was used to measure corneal curvature and the area of pterygium was calculated by image analysis software Image-Pro Plus V6.0.Patients were randomly divided into three groups based on the area of pterygium,namely≤4 mm 2,4.1 to 7 mm 2 and>7.1 mm 2.The Bland-Altman method was used to evaluate the agreement of two instruments.Results The mean K1 and K2 measured by the keratometer and IOL Master were not significantly different for pterygium area≤4 mm 2(K1:44.40±1.93 D vs.44.20±1.90 D,P>0.05;K2:44.36±1.83 D vs.44.21±1.69 D,P>0.05).There was high correlation between the two instruments(r=0.912,r=0.932 respectively)and the success rate of both instruments were 100%.For pterygium area of 4.1 to 7 mm 2,the mean K1 measured by the keratometer and IOL Master was statistically different(45.3±1.73 D vs.43.96±1.75 D,P<0.05),while no significant difference was observed for mean K2(44.72±1.64 D vs.44.26±1.91 D,P>0.05).The agreement between the two instruments was poorer(r=0.611,r=0.866 respectively)and the success rate was 97.33%and 100%,respectively.The mean K1 and K2 measured by the keratometer and IOL Master were significantly different for pterygium area>7.1 mm 2(K1:44.12±1.93 D vs.43.21±2.25 D,P<0.01;K2:44.24±1.65 D vs.45.15±1.41 D,P<0.01).There was correlation between the two instruments(r=0.732,r=0.542 respectively)and the success rate was 77.33%and 98.66%,respectively.The 95%limit of agreement for K1 and K2 was-2.241 to 3.474 and-4.170 to 2.132,respectively.Conclusions Oculus keratometer and IOLMaster 5.2.1 had good agreement for patients with pterygium area≤7 mm 2 and can be used interchangeably in clinics.However,for patients with pterygium area>7mm 2,the consistency between the two instruments was poor and the success rate of IOLMaster 5.2.1 was better.