Phu Jack, Bui Bang V, Kalloniatis Michael, Khuu Sieu K
Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia.
School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia.
Transl Vis Sci Technol. 2018 Mar 2;7(2):1. doi: 10.1167/tvst.7.2.1. eCollection 2018 Mar.
The number of subjects needed to establish the normative limits for visual field (VF) testing is not known. Using bootstrap resampling, we determined whether the ground truth mean, distribution limits, and standard deviation (SD) could be approximated using different set size () levels, in order to provide guidance for the number of healthy subjects required to obtain robust VF normative data.
We analyzed the 500 Humphrey Field Analyzer (HFA) SITA-Standard results of 116 healthy subjects and 100 HFA full threshold results of 100 psychophysically experienced healthy subjects. These VFs were resampled (bootstrapped) to determine mean sensitivity, distribution limits (5th and 95th percentiles), and SD for different '' and numbers of resamples. We also used the VF results of 122 glaucoma patients to determine the performance of ground truth and bootstrapped results in identifying and quantifying VF defects.
An of 150 (for SITA-Standard) and 60 (for full threshold) produced bootstrapped descriptive statistics that were no longer different to the original distribution limits and SD. Removing outliers produced similar results. Differences between original and bootstrapped limits in detecting glaucomatous defects were minimized at = 250.
Ground truth statistics of VF sensitivities could be approximated using set sizes that are significantly smaller than the original cohort. Outlier removal facilitates the use of Gaussian statistics and does not significantly affect the distribution limits.
We provide guidance for choosing the cohort size for different levels of error when performing normative comparisons with glaucoma patients.
确定用于建立视野（VF）测试正常范围所需的受试者数量尚不清楚。我们使用自助重采样法，来确定是否可以使用不同的样本量（）水平来近似真实均值、分布范围和标准差（SD），以便为获得可靠的VF正常数据所需的健康受试者数量提供指导。
我们分析了116名健康受试者的500份Humphrey视野分析仪（HFA）SITA标准结果，以及100名有心理物理学经验的健康受试者的100份HFA全阈值结果。对这些视野进行重采样（自助抽样），以确定不同“”和重采样次数下的平均敏感度、分布范围（第5和第95百分位数）和标准差。我们还使用了122例青光眼患者的视野结果，来确定真实结果和自助抽样结果在识别和量化视野缺损方面的表现。
样本量为150（SITA标准）和60（全阈值）时，自助抽样得到的描述性统计量与原始分布范围和标准差不再有差异。去除异常值产生了类似的结果。在样本量 = 250时，原始值和自助抽样值在检测青光眼性缺损方面的差异最小。
使用明显小于原始队列的样本量，可以近似得到视野敏感度的真实统计量。去除异常值有助于使用高斯统计，并且不会显著影响分布范围。
我们为在与青光眼患者进行正常比较时，针对不同误差水平选择队列大小提供了指导。
