Visual Field Expansion Through Innovative Multi-periscopic Prism Design

视野丧失的人报告与其他行人或物体碰撞，绊倒障碍物， 一般不允许开车。所有这些因素都严重限制了他们的独立性和生活质量。 视野丧失在脑损伤如中风、创伤或肿瘤后是常见的（偏盲视野丧失， HFL）或可能是由于视网膜色素变性、无脉络膜和晚期青光眼等视网膜疾病所致 （外围场损失，PFL）。大多数为扩大视野而开发的视觉辅助工具都取得了有限的成功。 设计用于将场景的部分从盲场移动到剩余视场的棱镜是最简单的， 最轻，最具成本效益的设备，用于视野丧失患者。这些棱镜装置创造了人造的 视觉岛可以帮助PFL和HFL患者检测和避免碰撞风险。一个行人在碰撞 过程将停留在患者视野中的固定位置。我们最近的分析发现， 当迎面而来的行人从45度角接近时，与其他行人的碰撞最高。 传统的棱镜装置可以将图像移动高达30°，但无法达到碰撞风险最高的区域。此外，本发明还 移位的图像在空间上（缩小）和颜色上失真，并且具有低对比度。当患者扫描 （看）朝向盲侧，有效扩展益处被当前棱镜设计限制为仅5°。因此，在本发明中， 当前设备的实际场扩展益处福尔斯低于最佳可能的理论预期。 为了克服这些限制，我们发明了一种新的光学装置，“多潜望镜棱镜（MPP）"， 其使用级联的半五棱镜（通常用于双筒望远镜）。而传统的棱镜使用 折射，MPP使用两次反射，导致45°的图像偏移（比目前的改进50 棱镜）而没有缩小、颜色失真或对比度降低的折射效果。MPP涵盖了 最大碰撞风险偏心率，并允许15°的有效眼睛扫描到盲侧（3倍于 当前的棱镜）。我们开发了这种新型设备的原型和初步配置， HFL和PFL患者的扩张。该字段扩展旨在便于检测行人 步行时的碰撞，或驾驶时交叉路口的危险（HFL）。我们提出了 PFL患者的设备允许向下的眼睛扫描和检测绊倒危险。 在这里，我们建议迭代地实现额外的改进，微调，并测试的有效性， MPP作为HFL或PFL患者的辅助工具。这将开始在实验室的可行性测试，并最终在 随机对照多中心临床试验。我们将比较患者的行人碰撞检测 性能与新型MPP设备和当前的棱镜设备，并评估他们的设备偏好。在 在多中心临床试验中，我们将使用创新的虚拟现实行人碰撞检测测试系统 这可以在诊所使用标准计算机和大屏幕电视轻松实现。我们还将进行 在多中心临床试验期间进行实验室测试，以进一步研究MPP在HFL驾驶中的功效。

Individuals with visual field loss report collisions with other pedestrians or objects, tripping over obstacles, and are commonly not permitted to drive. All of these factors severely restrict their independence and quality of life. Visual field loss is common following brain injuries such as stroke, trauma, or tumors (hemianopic field loss, HFL) or it may be due to retinal diseases such as retinitis pigmentosa, choroideremia, and advanced glaucoma (peripheral field loss, PFL). Most visual aids developed for field expansion have had limited success. Prisms designed to shift portions of a scene from the blind field to the residual seeing field are the simplest, lightest, and most cost-effective devices for visual field loss patients. These prism devices create artificial visual islands that can help PFL and HFL patients detect and avoid collision risks. A pedestrian on a collision course will stay at a fixed position in the visual field of the patient. Our recent analysis found that the risk of a collision with other pedestrians is highest when the oncoming pedestrian approaches from an angle of 45. Conventional prism devices can shift images up to 30° but do not reach this area of peak collision risk. Further, the shifted images are distorted spatially (minified) and in color and have low contrast. When patients scan (look) toward the blind side the effective expansion benefit is limited to only 5° by current prism designs. Thus, the actual field expansion benefit of current devices falls below the best possible theoretical expectation. To overcome these limitations, we invented a new optical device, the “multi-periscopic prism (MPP)”, which uses cascaded half-penta prisms (typically used in binoculars). Whereas conventional prisms use refraction, the MPP uses two reflections, resulting in a 45° image shift (improvement of 50% over current prisms) without the refraction effects of minification, color distortion, or contrast reduction. The MPP covers the peak collision risk eccentricity and permits 15° of effective eye scanning into the blind side (3 times wider than current prisms). We developed prototypes and preliminary configurations of this novel device to enable field expansion in HFL and PFL patients. This field expansion is intended to facilitate detection of pedestrian collisions when walking, or hazards at intersections when driving (HFL). We have proposed configurations of the device for PFL patients to allow for downward eye scanning and detection of tripping hazards. Here we propose to iteratively implement additional refinements, fine-tune, and test the effectiveness of the MPP as an aid for patients with HFL or PFL. This will begin with feasibility tests in the lab and culminate in a randomized controlled multicenter clinical trial. We will compare patients’ pedestrian collision detection performance with the novel MPP devices and current prism devices and evaluate their device preferences. In the multicenter clinical trial, we will use an innovative virtual reality pedestrian collision detection test system that can be easily implemented at clinics using standard computers and large screen TVs. We will also conduct a lab test during the multi-center clinical trial to further study the efficacy of the MPP in HFL driving.