Fan Xiang, Wu Lingling, Ding Aihua
Department of Ophthalmology, Peking University Third Hospital; Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital.
Department of Ophthalmology, Peking University Third Hospital; Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital;
J Vis Exp. 2020 May 25(159). doi: 10.3791/60673.
Recently, the isolated-check visual evoked potential (icVEP) technique was designed and has been reported to detect glaucomatous damage earlier and faster. It creates low spatial frequency/high temporal frequency bright stimuli and records cortical activity initiated primarily by afferents in the magnocellular ON pathway. This pathway contains neurons with larger volumes and axonal diameters, and it is preferentially damaged in early glaucoma, which can result in visual field loss. The study presented here uses standard operative procedures (SOP) of icVEP to obtain reliable results. It can detect visual function loss using a signal-to-noise ratio (SNR) corresponding to the defects of retinal nerve fiber layer (RNFL) in early stage open-angle glaucoma (OAG). A setting of 10 Hz and condition of 15% positive-contrast (bright) are selected to differentiate OAG patients and control subjects, with each check containing eight runs. Each run persists for 2 s (for 20 total cycles). A flowchart is constructed, which consists of pupil size and intraocular pressure over a 30 min rest period before each examination. Additionally, the testing order of eyes is performed to obtain reliable electroencephalographic signals. VEPs are recorded and analyzed automatically by software, and SNRs are derived based on a multivariate statistic. An SNR of ≤ 1 is considered abnormal. A receiver-operating-characteristic (ROC) curve is applied to analyze the accuracy of group classification. Then, the SOP is applied in a cross-sectional study, showing that icVEP can detect glaucomatous visual function abnormality in the central visual field in the form of SNR. This value also correlates with the thickness thinning of RNFL and produces high classification accuracy for early stage OAG. Thus, it serves as a useful and objective diagnostic technology for the early detection of glaucoma.
最近，独立检查视觉诱发电位（icVEP）技术被设计出来，并且据报道该技术能够更早、更快地检测出青光眼损伤。它产生低空间频率/高时间频率的明亮刺激，并记录主要由大细胞ON通路中的传入神经引发的皮层活动。该通路包含体积和轴突直径较大的神经元，并且在早期青光眼中优先受损，这可能导致视野丧失。本文介绍的研究使用icVEP的标准操作程序（SOP）来获得可靠的结果。它可以使用与早期开角型青光眼（OAG）视网膜神经纤维层（RNFL）缺陷相对应的信噪比（SNR）来检测视觉功能丧失。选择10Hz的设置和15%正对比度（明亮）的条件来区分OAG患者和对照受试者，每次检查包含八次运行。每次运行持续2秒（共20个周期）。构建了一个流程图，该流程图由每次检查前30分钟休息期内的瞳孔大小和眼压组成。此外，对眼睛的测试顺序进行安排以获得可靠的脑电图信号。VEP由软件自动记录和分析，并基于多变量统计得出SNR。SNR≤1被认为是异常的。应用受试者工作特征（ROC）曲线来分析组分类的准确性。然后，将SOP应用于一项横断面研究，结果表明icVEP能够以SNR的形式检测中央视野中的青光眼视觉功能异常。该值还与RNFL的厚度变薄相关，并且对早期OAG具有较高的分类准确性。因此，它是一种用于青光眼早期检测的有用且客观的诊断技术。
