Snapshot Retinal Imaging Mueller Matrix Polarimeter

描述（由申请人提供）：全世界有超过6500万人患有青光眼视力障碍。由于绝大多数患者很少出现青光眼症状，直到疾病的相对晚期，因此早期诊断和治疗对于保护视力至关重要。目前，青光眼的诊断是基于结构性视盘变化和功能性视野变化的组合。不幸的是，这两种测试都是相对主观的，因此青光眼的明确诊断可能会延迟或错过。然而，公认的是，视网膜神经纤维层（RNFL;即结构变化）的缺陷先于视野丧失的发作多达六年。许多成像方法，包括共焦扫描激光检眼镜（cSLO），光学相干断层扫描（OCT）和扫描激光偏振（SLP）已被开发，以允许这些微妙的结构缺陷的早期检测。其中，SLP提供了实现最早检测青光眼诱导的视网膜变化的希望。然而，由于SLP不是一个完整的偏振计，它的测量很容易由于RNFL的双衰减和去偏振的错误。因此，SLP的延迟分布的准确性受到未知的视网膜双衰减和去偏振的影响，降低了设备的灵敏度和特异性。此外，商业SLP仅对视神经乳头附近的视网膜的小部分进行成像，遭受运动伪影，并且是昂贵的（使用商业现货（COTS）部件和机械扫描仪的估计成本为$17k）。我们已经克服了这些限制与较便宜的（估计1万美元使用COTS部分），完整的穆勒矩阵（MM）旋光仪没有移动部件：快照视网膜成像穆勒矩阵（SRIMM）旋光仪。该设备避免了时间扫描，并允许在大视场内实时测量视网膜的完整偏振状态。这种装置有几个优点。首先，该设备的成本降低可能使其成为筛查患者的更实用和更具成本效益的工具。其次，由于该设计没有时间扫描，因此可以在单个眼底快照中观察到大的视网膜区域，而不需要复杂的图像配准算法。第三，以高时间分辨率获取完整MM数据集的能力将通过消除与去极化和去衰减相关的测量误差来提高该设备的临床灵敏度和特异性。这是北卡罗来纳州州立大学、南加州大学眼科研究所和亚利桑那大学之间的合作努力。具体目标是1.设计，校准，验证和测试眼底相机原型的快照视网膜成像米勒矩阵（SRIMM）偏振计。 2.设计并建立一个模型眼来表征和验证偏振计的性能。 3.通过使用高分辨率SD-OCT和Zeiss GDx进行比较测量，验证SRIMM旋光仪在兔子模型和有限数量的人类患者中的性能。

DESCRIPTION (provided by applicant): Worldwide, over 65 million people suffer visual impairment from glaucoma. Because the vast majority of patients rarely experience symptoms of glaucoma until relatively late in the disease, early diagnosis and treatment is essential in preserving vision. Currently, the diagnosis of glaucoma is based on a combination of structural optic disc changes and functional visual field changes. Unfortunately, both of these tests are relatively subjective and definitive diagnosis of glaucoma can be delayed or missed as a result. However, it is well accepted that defects in the retinal nerve fiber layer (RNFL; i.e. structural changes) precede the onset of visual field loss by as much as six years. A number of imaging methods including confocal scanning laser ophthalmoscopy (cSLO), optical coherence tomography (OCT) and scanning laser polarimetry (SLP) have been developed to allow early detection of these subtle structural defects. Of these, SLP provides promise in achieving the earliest detection of glaucoma-induced retinal changes. However, since SLP is not a complete polarimeter, its measurements are prone to error due to the RNFL's diattenuation and depolarization. Thus, accuracy of the SLP's retardance distribution is influenced by the unknown retinal diattenuation and depolarization, decreasing the device's sensitivity and specificity. Furthermore, commercial SLPs only image small sections of the retina in the neighborhood of the optic nerve head, suffer from motion artifacts, and are expensive (estimated cost of $17k using commercial off-the-shelf (COTS) parts and mechanical scanners). We have overcome these limitations with a less expensive (estimated $10k using COTS parts), complete Mueller matrix (MM) polarimeter with no moving parts: the Snapshot Retinal Imaging Mueller Matrix (SRIMM) polarimeter. This device avoids temporal scanning and allows a real-time measurement of the retina's complete polarization state over a large field of view. This device has several advantages. First, the device's cost reduction may make it a more practical and cost-effective instrument for screening patients. Second, since the design has no temporal scanning, large retinal areas can be observed, in a single fundus snapshot, without the need for complex image registration algorithms. Third, the ability to acquire a complete MM data set with high temporal resolution will improve the clinical sensitivity and specificity of this device by removing measurement errors related to depolarization and diattenuation. This is a collaborative effort between North Carolina State University, USC Eye Institute, and the University of Arizona. The specific aims are 1. Design, calibrate, validate and test a fundus camera prototype of a Snapshot Retinal Imaging Mueller Matrix (SRIMM) polarimeter. 2. Design and build a model eye to characterize and validate the performance of the polarimeter. 3. Validate the SRIMM polarimeter's performance in a rabbit model and in a limited number of human patients via comparative measurements taken with a high-resolution SD-OCT and a Zeiss GDx.