COMPARISON OF A-SCAN DEVICE ACCURACY
COMPARISON OF A-SCAN DEVICE ACCURACY
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DOI：
10.1016/s0886-3350(13)80737-7
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发表时间：
1990-03-01
影响因子：
2.8
通讯作者：
EPPLE, C
中科院分区：
文献类型：
--
作者：
GIERS, U;EPPLE, C
a扫描生物测量被认为是预测人工晶状体度数的有效辅助手段。据报道，测量的精度优于。+-。0.1毫米。三种生物识别装置在159人的检查中进行比较，每次检查重复多次。浸没法测得的轴向平均长度为23.77 mm；压扁和改进的压扁技术分别使距离缩短了0.1 mm和0.3 mm。轴向长度的测量值不具有相同的被测量概率，即使它们在一起很近。结果不呈光滑的高斯曲线分布；相反，即使在设备中使用电子门进行生物测定时，也可以看到我们选择的超声波波长模式上的值簇。当测量眼睛前段的短距离时，重测信度降低。白内障晶状体的晶状体厚度测量比健康的年轻眼睛更不易重现；另一方面，白内障患者的前房深度测量更为可靠。最后的发现可能部分是由于白内障晶状体内超声速度的不确定，部分是由于适应性。在白内障患者中，用浸没技术测量眼轴长度的重现性最好；在年轻健康的眼睛中，使用改良的压平装置测量的准确性较低。
A-scan biometry is recognized as a useful aid in predicting intraocular lens power. Measurements are reported to be accurate to better than .+-. 0.1 mm. Three biometry devices were compared in examinations of 159 persons, each examination being repeated several times. Axial length averaged 23.77 mm when mesured by the immersion technique; applanation and modified applanation techniques yielded 0.1 mm and 0.3 mm shorter distances, respectively. Measured values of axial lengths did not have the same probability of being measured, even if they were close together. Results were not distributed in smooth Gaussian curves; on the contrary, clusters of values, on the pattern of our choice of ultrasound wavelength, were seen even when biometry was performed with electronic gates in the devices. Retest reliability decreased when short distances in the anterior segment of the eye were measured. Measurements of lens thickness were less readily reproducible in cataractous lens than in healthy young eyes; anterior chamber depth, on the other hand, was measured more reliably in cataract patients. This last finding may have resulted in part from uncertainties about ultrasound velocity in the cataractous lens and in part from accommodatation. In cataract patients, axial length was measured most reproducibly by the immersion technique; it was measured less accurately in young healthy eyes with a modified applanation device.