Improved Search Coil Method for Measuring Eye Movements

描述（由申请人提供）：研究人员将开发一种新的设备，用于精确和方便地测量眼球运动。该装置是基于现有的和广泛使用的有线巩膜搜索线圈技术，其中一个环形隐形眼镜与一个小线圈的金属线放置在眼睛上，它的方向由外部磁场在线圈中感应电流的大小来确定。这种新设备在眼睛上使用了一种类似的巩膜隐形眼镜，但这种新镜片没有连接眼线圈和相关电子设备的导线。信号在眼线圈中产生，并由眼线圈附近的发射器/接收器检测到。透镜和线圈的方向由接收到的信号确定。现有的原型系统是进一步发展新系统的基础，新系统的发展将按照以下思路进行：1)评估现有系统的工程设计方案；2)制造嵌入合适线圈的新型隐形眼镜；3)扩展了测量眼扭转运动以及水平和垂直运动的系统；4)包装为主体可穿戴的独立系统；5)通过眼睛和晶状体运动的视频分析来评估性能。这种新方法保留了传统有线线圈的优点，即高分辨率和精度，大范围的运动，以及完整的三维方向测量。传统系统的最大缺点是从眼线圈到信号处理电子设备的导线。通过消除这些电线，产生了几个非常重要的优势。受试者的舒适度大大提高，因为从眼睛引出的外部电线经常会刺激眼睑，并对睫毛造成恼人的刺激。由于磁头放置在外部磁场中的限制减少，因此可以进行更大范围的实验；无脑实验，比如那些涉及运动和自发运动的实验，变得更加实用。也许最重要的是，避免了外部线路的损坏（电流系统中最常见的故障来源）。“无线”测量系统将为研究和临床带来巨大的好处。特别是，前庭和动眼病患者应该比现有的更能忍受新的线圈，允许更容易和更方便地记录更大一部分人群的精确眼球运动，对他们来说，传统的线圈通常是吓人的和不舒服的。

DESCRIPTION (provided by applicant): The investigators will develop a new device for the precise and convenient measurement of eye movements. The device is based on the existing and widely used wired scleral search coil technique, in which an annular contact lens with a small coil of wire is placed on the eye, and its orientation determined from the magnitude of the current induced in the coil by external magnetic fields. The new device uses a similar scleral contact lens on the eye, but the new lens has no wires leading from the eye coil to the associated electronics. Signals are induced in the eye coil, and detected from the eye coil, by a transmitter/receiver near the eye. The orientation of the lens and coil is determined from the received signal. An existing prototype system is the basis for further development of the new system, which will proceed along the following lines: 1) assessment of engineering design options with the existing system; 2) fabrication of new contact lenses with the appropriate coils embedded; 3) extension of the system to measure torsional eye movements as well as horizontal and vertical; 4) packaging as a stand-alone system that can be worn by the subject; 5) assessment of performance by video analysis of eye and lens motion. This new method retains the conventional wired coil's benefits of high resolution and accuracy, large range of movement, and complete three-dimensional measurement of orientation. The largest drawback of the conventional system is the wires that lead from the eye coils to the signal processing electronics. By eliminating these wires, several very significant advantages result. Subject comfort is greatly increased, as the external wiring leading from the eye often irritates the eyelid and causes annoying stimulation of the eyelashes. A greater range of experiments can be performed, since the placement of the head within the external magnetic fields becomes less restrictive; head-free experiments, such as those involving locomotion and self-generated movements become much more practical. Perhaps most importantly, breakage of the external wiring (the most common source of failure in current systems) is avoided. The "wireless" measurement system will be of tremendous benefit to both the research and the clinical communities. In particular, vestibular and oculomotor patients should tolerate the new coils much better than existing ones, allowing easier and more convenient recording of precise eye movements in a larger segment of this population, for whom the conventional coils are often intimidating and uncomfortable.