Objective Assessment of Visual Functions

视觉功能的客观评估，即视敏度，正变得越来越重要，通常是出于医学-法律原因。在早期的项目中，我们开发了一种适当的技术，产生一个相关的置信区间的敏锐度估计。这是常规使用，并已获得行业许可。经验表明，我们需要做两个主要的改进：第一个是解决一个紧急的方法问题：以前的视觉显示单元采用阴极射线原理。它们不再生产，因为LCD已经取代了它们。虽然对大多数应用有用，但LCD具有明显的亮度伪影，这使得它们非常不适合用于估计视觉功能。我们希望通过新的刺激机制来解决这个问题，这种机制可以在傅立叶域中消除人为亮度响应与模式响应之间的歧义。另一个问题是生理问题：所谓的陷波，即在中间空间频率区域的显著幅度损失;大约50%的受试者会出现这种情况。其生理基础尚不清楚。我们假设这是由于破坏性的叠加从一定程度上的皮质源的局部偶极子响应，或具有相反极性的响应分量的时间重叠。使用多通道记录（以前从未应用于这个问题）和高阶拉普拉斯推导结合广泛的视野范围和时间呈现率，我们的目标有两个：（1）提高我们对切迹生理基础的理解，（2）达到一个优化的刺激和记录范例，适用于所有患者的视觉功能的常规估计。

The objective assessment of visual function, namely visual acuity, is becoming increasingly important, often for medico-legal reasons. In an earlier project we developed an appropriate technique yielding an acuity estimate with an associated confidence interval. This is in routine use and has been licensed by industry. Experience has shown that we need to make two major improvements:The first is to solve an emergent methodological problem: previous visual display units employed the cathode-ray principle. They are no longer being produced, as LCDs have taken their place. While useful for most applications, LCDs have marked luminance artifacts, which render them quite unsuitable for estimating visual function. We hope to solve this problem with new stimulation regimes that disambiguate artifactual luminance responses from pattern responses in the Fourier domain.The other problem is a physiological one: the so-called notch, a marked amplitude loss in an intermediate spatial frequency region; this occurs in about 50% of all subjects. Its physiological basis is not understood. We hypothesize this to be due to the destructive superposition either of local dipole responses from an extent of cortical sources, or the temporal overlap of response components with opposite polarity. Using multichannel recordings (never applied to this question before) and higher-order Laplace derivations in combination with a wide range of visual field extents and temporal presentation rate, we are aiming at two goals: (1) to improve our understanding of the physiological basis of the notch, and (2) to arrive at an optimized stimulation and recording paradigm applicable to routine estimations of visual function in all patients.