Background: Standard automated perimetry does not sufficiently detect early open-angle glaucoma (OAG) in the clinic. New visual function tests for early glaucoma damage are therefore needed. The present study evaluated whether an isolated-check visual evoked potential (icVEP) could be used to detect visual function abnormalities in early-stage OAG and to explore potential related factors.
Methods: This was a cross-sectional study. Thirty-seven OAG patients with early-stage visual field loss (mean deviation ≥ -6.00 dB) detected by the Humphrey Field Analyzer (30-2 SITA program) and 26 controls were included in this study. Optical coherence tomography (OCT) was used to detect retinal nerve fiber layer (RNFL) defects. The icVEP preferentially evaluates the magnocellular-ON pathway. VEPs were recorded and signal-to-noise ratios (SNRs) were derived based on multivariate analysis. Eyes that yielded an SNR ≤1 were considered abnormal. Receiver operating characteristic (ROC) curve analysis was used to estimate the accuracy of group classification. Correlations between SNRs and related factors were analyzed.
Results: Based on an SNR criterion of 1, the icVEP had a sensitivity of 62.2% and a specificity of 92.3% for diagnosing early-stage OAG with 74.6% classification accuracy. The ROC curve analysis, however, suggested that an SNR criterion of 0.93 would produce the highest classification accuracy (77.3%). Both RNFL thinning in the temporal superior quadrant on OCT and number of abnormal test points in the central 11° visual field (pattern deviation, P < 0.5%) significantly correlated with the SNR (P < 0.05).
Conclusions: The icVEP detected visual function abnormalities in approximately 3/5 of eyes with early-stage OAG with greater than 90% specificity. SNR correlated with both a decrease in RNFL thickness and severity of central visual field loss.
分离格栅视觉诱发电位在早期开角型青光眼患者中的应用 摘要 背景: 标准自动视野计(SAP)在临床中无法充分地检测早期开角型青光眼。我们需要新型的视功能检查法来检测早期青光眼损伤。本研究将评估分离格栅视觉诱发电位(icVEP)在检测早期开角型青光眼(OAG)视功能异常中的能力，探索其潜力及相关因素。 方法: 这是一项横断面研究。37名结合标准自动视野计（Humphery视野分析仪，30-2 SITA程序）检测结果（MD≥-6dB）诊断为早期视野异常的早期OAG患者，以及26名健康志愿者被纳入该研究。光学相干断层扫描（OCT）用于检测OAG患者的视网膜神经纤维层（RNFL）缺损。icVEP能够特异性地刺激视网膜神经节细胞的大细胞（M细胞）ON通路。刺激产生视觉诱发电位被记录下来，通过多元统计方法得到信号噪声比（SNR）。SNR≤1被考虑为icVEP结果异常。受试者工作特征（ROC）曲线用于分析SNR分组的准确度。进一步分析相关因素与SNR的相关性。 结果: SNR判定值为1时，icVEP对早期OAG诊断的灵敏度为62.2%、特异度为92.3%，准确度为74.6%；而当SNR判定值为0.93时准确度达到最高值(77.3%)，相应的灵敏度59.5%、特异度100%。颞上象限RNFL厚度的变薄以及中心11°视野的异常测试点数（模式偏差图，P<0.5%）均与SNR显著相关（P<0.05）。 结论: icVEP能够检测出早期OAG患者的近3/5存在青光眼性视功能异常，特异度超过90%；其评价指标SNR与OCT测得的RNFL厚度的下降以及中心11°视野缺损的程度均有相关性。.
Keywords: Cross-Sectional Study; Isolated-Check; Open-Angle Glaucoma; Signal-To-Noise Ratios; Visual Evoked Potential.