Functional Testing for Glaucoma

描述(由申请人提供)：青光眼是美国和世界范围内导致失明的主要原因。该项目的长期目的是改进青光眼的功能测试。对患者的评估和随访目前依赖于自动视野检查来提供视野的功能测试。然而，使用视野检查评估进展和/或治疗反应的能力受到高度变异性的阻碍，特别是在中度或严重青光眼损害的地区。我们实验室和其他实验室最近的发现通过挑战关于这项测试的关键假设，促进了我们对视野检查的理解。这项提议旨在利用这些进步来解释和减少测试的可变性。这将提高当前功能测试的准确性、效率和实用性，在研究和临床环境中产生立竿见影的影响，并为下一代仪器和算法奠定基础。第一个具体目标是产生一个准确的和生理上合理的视野检查有效动态范围(EDR)的测量。据推测，青光眼缺陷的视野检查中使用的极高对比度刺激会使视觉系统的反应饱和。对比度响应函数中产生的非线性将导致检测概率渐近到100%以下，这解释了受损区域灵敏度的高变异性。EDR的极限将被定义为对比度，超过该对比度不能假定响应线性。这将通过收集中度或重度青光眼受试者的视力曲线来测量。同样的技术将被用来确定是否通过增加刺激大小来延长EDR。第二个具体目标是推导和测试空间滤波器，以减少变异性。这将是第一个同时基于视野中其他位置的敏感度和视神经头结构的过滤器。第三个具体目标是评估使用线性灵敏度标度的潜在效用，而不是目前的对数分贝标度。首先，将推导和测试一个有效的线性比例阈值算法，以确定它是否会减少测试之间和结构-功能关系中的可变性。其次，将检查中央视野的线性尺度的全局指数，以确定在评估进展时，与当前的分贝尺度指数相比，它们是否提供更好的预后价值。这三个目标是相辅相成的。预计通过将这些目标结合起来，视野检查的可变性将得到更好的理解，并显著降低。在像视野检查一样常用的检查中的这种改进将对未来的临床实践产生重大影响。 公共卫生相关性：该项目旨在解释和减少青光眼患者视野功能测试中观察到的变异性。这将使更早和更准确地评估患者的当前状态和对治疗的反应。它将提高设计适当和具有成本效益的个性化管理策略的能力，以保护视力，目的是保持患者的生活质量。

DESCRIPTION (provided by applicant): Glaucoma is a leading cause of blindness both in the US and worldwide. The long-term purpose of this project is to improve functional testing in glaucoma. Assessment and follow-up of patients currently relies on automated perimetry to provide functional testing of the visual field. However, the ability to assess progression and/or response to treatment using perimetry is hampered by high variability, especially in areas of moderate or severe glaucomatous damage. Recent findings by our laboratory and others have advanced our understanding of perimetry by challenging key assumptions about the test. This proposal aims to use these advances to explain and reduce the test variability. This will improve the accuracy, efficiency and utility of current functional testing, giving immediate impact in both research and clinical settings, and laying groundwork for the next generation of instruments and algorithms. The first Specific Aim is to produce an accurate and physiologically justified measure of the Effective Dynamic Range (EDR) of perimetry. It is postulated that the very high contrast stimuli used by perimetry in glaucomatous defects saturate the response of the visual system. The resultant nonlinearity in the contrast-response function would cause the detection probability to asymptote below 100%, explaining the high variability in sensitivities in damaged areas. The limit of the EDR will be defined as the contrast beyond which response linearity cannot be assumed. This will be measured by collecting frequency-of-seeing curves in subjects with moderate or advanced glaucoma. The same technique will be used to determine whether the EDR is extended by use of an increased stimulus size. The second Specific Aim is to derive and test a spatial filter to reduce the variability. This will be the first filter to be based both on sensitivities at other locations in the visual field and on the structure of the optic nerve head. The third Specific Aim is to assess the potential utility of using a linear scale for sensitivity, rather than the current logarithmic decibel scale. First, an efficient linear-scaled thresholding algorithm will be derived and tested, to determine whether it will reduce variability both between tests and in the structure-function relation. Second, linear-scaled global indices of the central visual field will be examined, to determine whether they offer improved prognostic value compared with current decibel-scaled indices when assessing progression. The three aims are complementary. It is anticipated that by combining these aims, variability in perimetry will be better understood, and significantly reduced. Such an improvement in a test as commonly performed as perimetry will significantly impact future clinical practice. PUBLIC HEALTH RELEVANCE: This project aims to explain and reduce the variability observed in functional testing of the visual field in patients with glaucoma. This will allow earlier and more accurate assessment of a patient's current status and response to treatment. It will improve the ability to design an appropriate and cost-efficient personalized management strategy to preserve vision, with the aim of maintaining a patient's quality of life.